Beautiful Blue Garden Blooms
There’s just something so incredibly transcendent about a blue flower. That color. That color. Takes me somewhere else… Ok, I’m back. And I’m going to show you some of the beautiful blue blooms that grow in my garden. Ten different kinds, in fact. With pics and info on how to grow ’em.
Table of Contents
Introduction
It was my friend, Richard, to whom the real credit for this article goes. Don’t get me wrong. I love blue flowers. LOVE them. But to dedicate an article entirely to them, and only them? Blue flowers? Only blue flowers? Gotta admit, the thought hadn’t really crossed my mind. Until Richard surprised me with an admission.
It happened on Twitter. I’d tweeted a shot of a blue bloom (along with some basic info) from one of the perennials which grow in my garden’s “Blue and White Hill” planting feature. This particular perennial boasts one of the absolute truest blue flowers in the plant world, and sits right at the very top of the list of the most beautiful blue blooms in my garden. (You’re gonna read all about it in this here piece.) Richard replied to this tweet quickly. Amazingly, he hadn’t heard of this particular plant before. I found this amazing because 1) Richard is a brilliant guy who happens to know quite a bit about quite alot of different things. 2) One of the things Richard knows quite a bit about is gardening – his own garden is mindblowingly beautiful. 3) Richard is an English gardener, and anyone with half a brain knows that this is the best kind.
I’ll also mention here that Richard is one of the very brightest stars in my own social media sky. He’s a fine gentleman with an exceptionally keen wit, a terrific scathing sense of humor, a brilliant (and quite professional) mastery of the written word, and, above all, great heart. I respect the hell out of him, and I respect his knowledge. If this particular item was unknown to him, I thought there was likewise probably an entire legion of knowledgeable friends, readers, gardeners, etc to whom its introduction would prove both necessary and beneficial. Needless to say, my hunch was correct. More of my knowledgeable, well-respected, and dear friends (Jaynie, et al) indeed came forward on Twitter’s platform to ratify this enchanting blue flower’s mysterious status.
So, ultimately, I have Richard to thank for prompting the writing of this piece. I decided to release my knowledge of this bloom in the form of an article here. I made a split-second, subsequent decision to include some shots and info on nine other cerulean beauties which lurk in my garden. Blue is a fabulous color for a flower, after all. For any flower. It just wouldn’t be right to let only one beautiful blue garden bloom hog the spotlight.
Note to readers: When I tout the proficiency of English gardeners, I do not exaggerate. Two cases in point: Click here to experience the artistry of UK master gardener and garden designer Nick Webb, and click here to learn master gardener Sam Preston’s methodology for creating and maintaining the health and beauty of her award-winning UK garden.
10 Beautiful Blue Garden Blooms
The subject of blue blooms is a loaded one. There are so many shades and variations of the color blue, and there are so many flowering plants that offer their own unique take on the color. I’m convinced that it’s impossible to pick the absolute best beautiful blue garden blooms. What I tried to do for the purposes of this article, within the limits imposed by my own garden (I’ve got about 20 different perennial varieties which offer blue blooms), was pick the ten blues which, I swear to God, come as close as possible to actually emitting a discernable resonance. I feel that each of the blooms I’m including here possesses an aura, a vibe… indeed, a resonance. These flowers rouse themselves and glisten in the morning light, and they’re humming and gleaming while they smile up at the bright sun of the afternoon. At day’s end, they nod and glow and shimmer and beckon from within the quiet, crepuscular embrace of the gloaming. These are the blue flowers of my garden with whom I commune. The qualifying parameters of my selection process have been set according to these, my observations and feelings. There is variation of blue shade, of blue timbre, from species to species, and from flower to flower. They are, after all, individuals. But each of these ten meet my specs. They all talk to me. And I talk to them.
Although the plant which prompted the writing of this feature – the subject of Richard’s initial comment – happens to be the first you’ll find in this lineup, the list is written in no particular order. As far as beautiful blue garden blooms are concerned, the following 10 plants offer the best and the bluest of my own garden’s cerulean splendor. Some are tall and stately, some are groundcover, some are shrubs, some grow in clumps, and some are compact little mounds. All are perennials, as is everything that grows in my garden. And all are experts in the art of the blue flower.
With each one on the list, you’ll get some pics, some vitals, and some of my own field notes. And now, I’ve blabbed enough. it’s time to meet my garden’s top 10 beautiful blue garden blooms. Here you go…
1. True Blue Border Gentian (Gentiana x intermedia ‘True Blue’)
The basics.
Height – 18″-30″. Spread – 12″ -18″. Light – full sun to part shade. Bloom color – vibrant, rich blue. Bloom time – mid summer through early fall. Foliage – deep green and herbaceous. Hardiness – zones 4-8. Growth rate – slightly slow to medium growth rate. Pollinators – bees, butterflies, hummingbirds.
Notes from the field.
In my hunt for the bluest of beautiful blue garden blooms, I stumbled upon the genus Gentiana, to which my hybrid belonged. Native to alpine regions throughout the world, the genus is notoriously difficult to grow anywhere beyond where it naturally occurs. Incredibly beautiful plants, but difficult to grow in a cultivated, ornamental environment. I loved the thought but didn’t want the headache. (Shit. I really wanted these.) I ended up getting my way because the science of hybridization, I’d discovered, had produced a number of exotic beauties which were fit for a cultivated, ornamental garden. My x intermedia was such a hardy, hybridized species. I planted seven of these stunners in very early May of 2021, and have since come to know them on an intimate basis. Although they’re incredibly tough and hardy (they survived a vole infestation last year with no evident ill effects), they were fairly slow growing and did not flower their first summer. I ordered mine online from an excellent, highly reputable nursery. They arrived as healthy babies in small, 3″ pots. Their growth rate was steady, but slow. This year, they emerged beautifully in very early spring, first poking their heads out of the ground around the third week of March. They grew back in substantially more robust fashion in this, their second year, and flowered for the first time in early September. True Blue border gentians do well in full sun to part shade light conditions. The flowers of the True Blue border gentian present the truest blue of any flower I’ve ever seen. These were worth the research and worth the investment.
Suggestions for planting True Blue border gentians.
Plant True Blue border gentians as soon as you get them. They can be planted in the spring or summer, but because of availability issues, you’ll want to order them online (I have never seen these offered at any of the numerous local nurseries which I personally visit) in winter. If you wait until spring to order them, they may not be available. Plant them with their crowns even with (or a bit higher than) the soil surface. In terms of planting location, depending on the heights of surrounding plants, True Blue border gentians look great in both front and mid borders.
Soil. My gentians prefer a moist but well-drained soil, although they’re amazingly drought-tolerant. You’ll obviously want to maintain decent soil moisture for newly planted individuals. I bedded mine in the potting soil I universally use throughout my garden. It’s slightly acidic and somewhat loamy. My gentians have thrived beautifully in this medium, although my research tells me that they’re not terribly choosy about soil pH (anywhere from just above to just below 7 on the pH scale is apparently fine). They received a feeding of Espoma Plant-tone fertilizer this spring, and another light feeding in mid summer.
Water. As these plants prefer moist, well-drained soil, it’s best to water regularly. This is especially important for newly planted individuals. Again, in spite of their preference for moist soil conditions, once these plants are established, they’re very drought-tolerant.
Pruning and/or deadheading. I haven’t deadheaded mine this year, and I probably won’t. They began blooming so late in the season, I’m pretty sure that deadheading will not encourage new bloom formation. If they bloom earlier next year, I may experiment. I cut mine down to the ground in late fall/early winter last year.
Companion planting. My gentians grow in my blue and white hill planting feature, situated between a drift of shasta daisies in the front border, and white garden phlox behind them. The blue and white color combo is beautiful, but the phlox need to be managed – they’re assertive spreaders and could possibly overwhelm the gentians.
2. Virginia Bluebells (Mertensia virginica)
The basics.
Height – 1′-2′. Spread – 12″ -18″. Light – partial to full shade. Bloom color – vibrant light blue. Bloom time – Late April through late May in zone 5B/6A. Foliage – herbaceous and ephemeral. Grows and flowers late winter through mid spring and then dies back until the next year. (By the end of June, they’re basically gone until March of the following spring.) These native wildflowers spread via rhizomes and self-sowing, and fully colonize where they’re planted. Hardiness – Virginia Bluebells are hardy in zones 3 – 8. Growth rate – medium. Pollinators – bees and butterflies. Bonus: deer and rodents avoid these plants.
Notes from the field.
I planted three individuals in mid-March of 2021 as bareroots. They grew successfully, though only one flowered. This plant is best planted as a bareroot. By their second year, mine had expanded and begun to spread out through their rhizomatous growth habit. They are naturalizing/colonizing as expected. Mine grew large and flowered profusely in their second year.
Suggestions for planting Virginia Bluebells.
Plant them as soon as they arrive. You’ll be planting these in late winter/early spring. One of the benefits of ordering from a reputable online nursery is that your plants will be shipped to you at the proper planting time for your hardiness zone. Get your plants in the ground as soon as they arrive. Mine were delivered in early/mid March, and I planted them immediately. These plants can handle the cold. The bareroots of these plants are thick and sort of tuberous in appearance, and what they are, actually, are thick rhizomes. I planted mine so that the top of the root was approximately 1-1/2″ below the surface of the soil. I added approximately 1/2″ – 3/4″ of wood chip mulch over the soil. They sprouted within a week of planting them.
Soil. These plants like moist soil that’s fairly rich in organic matter. They grow naturally in forests and wooded environments so it follows that they flourish in an organic type of soil. I bedded these plants in the same potting soil I use throughout the rest of my garden. This slightly acidic soil contains a slow-release fertilizer. Aside from this, my Virginia Bluebells received no fertilizer in their first year. Once they began leafing out after emerging this year, I applied a topical sprinkling of Espoma Plant-tone. This was evidently beneficial as my Bluebells exploded with growth and blooms. The flowers of these US Midwest natives are incredible clear sky blue, and are among the most beautiful blue garden blooms I have ever seen. I featured these plants, along with the next blue flower on this list, in my article of earlier this year featuring some excellent late winter/early spring cold weather planting recommendations.
Water. Water these natives frequently enough to prevent the soil from drying out. Remember, their natural environment is the forest. They’re never exposed to blazing sun and drought. Think shady and moist for Virginia Bluebells.
Pruning and/or deadheading. Nope. They’re basically gone by the end of June or early July. If you’d like, cut the dead brown foliage down to the ground. I left mine intact for awhile after it had died back, and by the time I got around to cutting it off it had almost entirely decomposed. I left it in place to serve as compost.
Companion planting. Because these guys are gone so early in the summer, it’s a good idea to have something growing nearby that somewhat overlaps them in terms of growth periods and planting bed space. I didn’t want an empty space in my garden so early in the summer after my bluebells went to sleep. I planted them near my white old-fashioned bleeding hearts, a huge, bigleaf hydrangea, a cluster of hostas, and some Biokovo hardy geraniums. All of these really start to hit their stride when the bluebells die back. This dynamic guarantees that there’s no vacant space in that particular part of the garden.
3. Cobalt Blue Double Primrose (Primula vulgaris ‘Belarina Cobalt Blue’)
The basics.
Height – 6″-8″. Spread – 10″-12″. Light – mostly sun to mostly shade. Bloom color – deep, rich blue. Bloom time – spring, and sometimes again in fall. Foliage – thick, rich green. Evergreen, semi-evergreen. Hardiness. hardy in zones 4 – 8. Growth rate – moderate/medium. It can take one of these cuties a couple of years to reach its full size. Pollinators. I have occasionally seen bees, moths, and butterflies visiting these flowers. This plant has a moderate/medium growth rate. Bonus: charming, tough little plants that are not afraid of the cold, or of anything else, for that matter.
Notes from the field.
I’ve got a fairly large population of primroses – of different species and different varieties – in my garden. I purchased some of my primroses two winters back from a local nursery, and some from three separate, highly reputable online nurseries. My Cobalt Blues all came from one nursery online. All of my primroses (including the Cobalt Blues) were in the ground by the end of the second week of that March, with the exception of my Cottage Double Whites. The excellent online nursery which sold the Double Whites to me was concerned about the batch that I’d ordered in the winter. So they rooted a whole new batch for me for a scheduled summer delivery. I can now tell you that these plants – all species and varieties of hardy primula, including the Cobalt Blues – can be bedded outdoors in both late winter and high summer in hardiness zone 5B/6A. I was a little surprised that each and every one of them handled the shock of being transferred from pot to earth in extreme temperature situations with no trouble whatsoever. They even started blooming as early as late winter the same year they were planted. What’s even more amazing is their ability to remain evergreen in frigid temperatures. Over the course of this past winter, which was notably harsh, these plants were, at various times, encased in ice, buried under two feet of snow, and exposed to single digit temperatures and subzero windchills. In addition to breezing through the brutal winter, these little guys survived a nasty vole infestation in my garden which persisted into mid autumn. While numerous, less hardy perennials succumbed to the dietary predilections of these pernicious pests, my primula population persevered. I’m pretty proud of my primroses. Alliteration notwithstanding, these tough little plants are beautiful and almost supernaturally hardy. Some of them were chewed to the ground by the voles in my garden last year, and they rebounded and once again leafed out and set buds, and flowered beautifully. These little plants are simply incredible.
My Cobalt Blue primulas can tolerate mostly shade to mostly sun. They grow and bloom well in both conditions.
And these diminutive dynamos are blooming powerhouses. They can bloom continuously from late winter/early spring right up to the beginning of summer. A few of mine even rebloomed in fall. The combination of their thick, tough green foliage and stunning blue blooms creates a most alluring vibe in the garden. All of my primulas are located at the front borders of their planting beds along my garden’s walking paths, which will soon be paved with limestone (so yeah, primrose paths it is). Their combination of diminutive size, gorgeous color and form, English cottage garden charm, and almost palpable “attitude” make primroses impossible for me to resist. These little pitbulls of the plant world are an indispensable part of my garden’s aesthetic. Are they the most beautiful blue blooms in my garden? Let me just say that on a scale of 1 to 10, they’re an 11.
Suggestions for planting Cobalt Blue double primroses.
Plant them as soon as you get them. Again, your local nursery will have primulas ready for retail purchase, and reputable online nurseries will ship them, at the correct planting time for your zone. In 5B/6A, that’s generally late winter/early spring. These primroses are good to go in the cold. As long as you can dig and work the soil in your garden, plant them. As mentioned, however, I have planted primroses in the heat of summer and they performed beautifully. And again, these are perfect front border plants which look exceptional when planted along walking paths.
Soil. When I first bedded my primulas, I again used the slightly acidic potting soil with the pre-mixed slow release fertilizer (N-P-K ratio of .10-.08-.06). I did nothing to amend either the soil’s pH or nutrient levels for the first year my primulas were in my garden. Now, however, I do use Espoma’s Plant-tone (N-P-K ratio of 5-3-3) to fertilize them. Their soil remains slightly acidic, so at this point, there’s no need for me to amend its pH levels. My primroses definitely like their soil to be moist and well-drained.
Water. Primroses enjoy cool damp locations. It’s important to keep them watered, but definitely not soggy. Once they’re established, they become a bit more tolerant of dry spells, but not terribly so. Keep their soil moist, but again, not wet or soggy. If a primrose’s roots become waterlogged, the plant will quickly die.
Pruning and/or deadheading. Yep. You’re going to want to do both. Even though these plants are really little and really close to the ground, and it’s a pain in the ass to get down to their level (at least it is for me), it is DEFINITELY worth your while to deadhead spent blooms and to prune back compromised foliage. This will keep your primulas looking green and healthy, and will encourage profuse and continuous blooming. And trust me, you’re gonna want these little guys to keep blooming.
Companion planting. Primulas look great and perform beautifully in any number of planting scenarios. In my garden, I grow blue and white varieties together in clusters. I’ve also got them growing beneath taller plants, and peeking out between and from beneath hostas and hellebores. They’re a great complement to almost any nearby taller plant and, of course, to one another. They even share space with two other beautiful blue garden blooms on this list: woodland forget-me-nots and hardy plumbago.
I love Espoma’s organic fertilizers. Plant-tone is the one I use for the majority of the plants in my garden, and it’s the one that my beautiful blue garden blooms depend on. It’s got an N-P-K ratio of 5-3-3 and is a great all-purpose organic fertilizer. It works perfectly for an incredibly wide variety of ornamental plants. Again, Espoma Plant-tone is the food that most of my plants get. And they love it. You can order this product here, directly from Amazon, by clicking the #advertisement link.
4. Takion Blue Peach-Leaved Bellflower (Campanula persicifolia ‘Takion Blue’)
The basics.
Height – 16″-24″. Spread – 10″ -12″. Light – partial to full sun. Bloom color – vibrant blue-lavender. Bloom time – late spring through summer in zones 5B/6A if deadheaded. Foliage – herbaceous, rich green, with dense basal foliage and slender foliage along flower stalks. Hardiness – hardy in zones 3 – 8. Growth rate – medium. Pollinators – butterflies, hummingbirds, and bees. Bonus: strong flower stalks don’t require staking and diligent deadheading results in flowers almost all summer long.
Notes from the field.
I planted mine as full-sized plants in early May this past spring. With proper deadheading, they flowered all summer. These plants seem susceptible to crown/stem rot. I lost one individual because I believe it was set too deeply in the ground when I initially planted it. The combination of moist mulch and soil against the stems of this plant resulted in its death, I believe. I planted a few tiny babies from 3.5″ pots this fall. I’m hoping they’ll bloom next spring/summer. Due to the fact that these are not terribly rapid growers, I may have to wait until the following year for flowers. And speaking of flowers… These really strong bloomers put on a floral display that absolutely demands attention. The blooms literally glow, and they feature one of the most beautiful shades of blue in my garden.
Suggestions for planting Takion Blue peach-leaved bellflowers.
Plant them as soon as you get them. They can be planted in the spring, summer, or fall. I’ve planted mine successfully in both the spring and late summer/early fall. Plant them with their crowns even with (or a bit higher than) the soil surface in order to avoid crown/stem rot. In terms of location, these are excellent front or mid border plants.
Soil. My Takion Blues prefer a moist, well-drained soil. Avoid constantly soggy soil. This will rot the roots and crown and kill the plant. I bedded mine in my usual, slightly acidic potting soil. Research told me that these plants prefer a neutral or slightly alkaline soil. I amended their specific bedding soil with a moderate dose of garden lime to bring the pH to just a hair above 7.0. Like many of my other plants, these received a topical feeding of Espoma Plant-tone fertilizer this spring, and another light feeding in mid summer.
Water. New plants will need more regular watering. In spite of this plant’s preference for moist soil, it is drought-tolerant once it’s established.
Pruning and/or deadheading. Deadhead regularly to encourage blooming. I cut my dead and dying blooms off at the point where an individual flower stem meets the flower stalk. I was able to enjoy flowers from these guys all summer long.
Companion planting. My Takion Blues grow in my blue and white hill planting feature, among white garden phlox, shasta daisies, and blue and white grape hyacinths.
Espoma Organic Garden Lime is a great product for raising alkalinity levels in soil. It can be mixed with the bedding soil, or used to top dress soil around plants which are already in the ground. I used this to amend my Takion blues’ soil. Click the #advertisement link to order this product here, from Amazon.
5. The Original Bigleaf Hydrangea by Endless Summer® (Hydrangea macrophylla ‘Bailmer’)
The basics.
Height – 3′-5′. Spread – 4′-5′. Light – partial shade to partial sun. Bloom color – a range of blue shades (in acidic soil). Bloom time – summer. Foliage – deciduous, rich green, serrated leaves. Hardiness – hardy in zones 4– 9. Growth rate – medium to fast. Pollinators – butterflies and bees. Bonus: strong flower stems easily support huge flowers which can be up to 8 or 9 inches across in size.
Notes from the field.
I planted four of these as first year potted individual three summers ago in my garden’s blue and white hill planting feature. Research told me that these plants required acidic soil in order to generate truly blue blooms (in alkaline soil, they’ll bloom pink). I amended the already slightly acidic soil in their individual beds with Espoma Soil Acidifier in order to drop the pH to below 6.5. This definitely resulted in blue blooms. These plants will droop if they’re exposed to full, direct sun for prolonged periods of time. Mine are planted in mostly shade to partial sun locations, and are watered fairly frequently to prevent drooping. Although these shrubs are technically deciduous, they’ll bloom on both old and new wood. I’ve pruned a couple of these shrubs back (in late winter) in order to eliminate compromised stems. They regenerated quickly and successfully, and did indeed bloom on the new stems. I do apply a topical dosing of soil acidifier to these shrubs in the early spring, again in mid summer, and finally in late fall. This maintains the fairly acidic medium they require in order to produce blooms in blue shades. My bushes, growing in this acidic soil, produce amazing, giant, blue blooms in a fascinating range of shades. The blooms, even on one bush, can range from sky blue to almost royal blue. The colors are amazing, and the variation in shade creates the most incredible color wave. One look at these massive flowers and it’s easy to see why they’ve made this beautiful blue garden blooms top ten.
Suggestions for planting The Original bigleaf hydrangea.
Plant them as soon as you get them. They can be planted in the spring, summer, or fall. My four Originals were all planted in mid summer, but I’ve planted other varieties of Endless Summer® bigleafs successfully in spring, mid summer, and late fall. They adjust well to virtually any planting depth (within reason), but stems buried too deeply can be subject to grazing by tunneling rodents like voles. Hydrangea aerial stems display an interesting property. If such stems are in contact with the soil at the point of a node, subterranean roots will emerge from that node (not the associated internode) and begin to root in the soil at that point. This is one reason that planting depth can vary to some degree with these shrubs. These shrubs look great planted in a back border underplanted with smaller perennials, as a front border fixture lining a path, or en masse as a hedgerow.
Soil. My Originals do beautifully in moist, well-drained soil. They’ll grow fine in soil that ranges from acidic to alkaline, but, as already stated, the color of the blooms is contingent upon pH level. These bushes will bloom blue in acidic soil, and pink in alkaline soil. I want blue, so I keep my soil’s pH between 6 and 6.5. I fertilize them three times a year with Espoma Plant-tone.
Water. Water these plants regularly. Especially when first planted. I encourage my established shrubs to further extend their root systems by periodically withholding water. This forces the roots to extend further into the soil in search of moisture. But I do this infrequently, and for only brief intervals. These plants love water and will droop when it’s denied them.
Pruning and/or deadheading. Deadhead regularly to encourage blooming during the growing season. Follow the stem down to the first healthy pair of leaves (you’ll often see nodes at their junction with the stem) and make the cut just above that point. I often leave dried blooms in place in the late fall and winter for visual interest. Cut dead stems back whenever you see them.
Companion planting. My Originals grow well with other hydrangeas and a number of other plants, as well, in my garden’s blue and white hill planting feature. Click here to read about their immediate neighbors.
I always use Espoma Organic Soil Acidifier to lower soil pH for plants like my blue hydrangeas and my rhododendrons. It’s very effective and allows acid-loving plants like these to better absorb nutrients from fertilizing products. Click the #advertisement link to order it here, from Amazon.
6. Blue Line Corydalis (Corydalis curviflora ‘Blue Line’)
The basics.
Height – 16″-18″. Spread – 22″ -24″. Light – full shade to partial sun. Bloom color – clear, “electric” blue. Bloom time – spring through summer in zones 5B/6A. Foliage – evergreen/semi-evergreen. Hardiness – hardy in zones 5 – 9. Growth rate – medium. Pollinators – butterflies, moths, and bees. Bonus: one of the most uniquely colored and uniquely shaped blooms in my garden. The scent of the blooms is incredibly sweet, and the plants are pollinator magnets.
Notes from the field.
I planted three of these plants as little more than bareroots in the early spring of 2021. Only two survived the spring (which is probably good because three successful plants would have resulted in overcrowding) and grew stronger and larger over that summer, but did not bloom. This year, they grew even larger, and flowered fairly spectacularly. The color (which can best be described as clear, “metallic” blue), shape, and scent of the little blooms are, respectively, incredibly beautiful. This amazing color and flower form made my Blue Line corydalis a shoo-in for my top ten list of beautiful blue garden blooms. These plants do very well in partial shade/partial sun conditions, and appreciate moist, well-drained soil. They self-sow fairly aggressively, and I’m continually plucking them to keep them from overrunning their section of the planting feature.
Suggestions for planting Blue Line corydalis.
Plant them as soon as you get them. They are best planted in the spring or fall. My Blue Lines were planted successfully in the early spring of 2021, and my massive Yellow corydalis was planted in the fall of 2020. Both species of plant benefitted from these planting times. Plant them with their crowns even with (or a bit higher than) the soil surface in order to avoid crown/stem rot. These look great in a front border overlapping a path, or in a mid border surrounded by complementary colored bloomers.
Soil. My Blue Lines (as well as my Yellow corydalis) like moist, well-drained soil. Neither my Blue Lines nor my Yellow seems too fussy about soil pH. The soil in which all three of these plants grow has ranged, at various times, from slightly acidic to slightly alkaline. Each plant’s amazing vitality and vigorous blooming appeared unaffected by these fluctuations in soil pH.
Water. New plants will need more regular watering. Established plants and newly planted individuals respond well to frequent waterings but do not tolerate soggy roots. Blue Lines (and Yellows) are actually pretty drought-tolerant once established.
Pruning and/or deadheading. I never even try to deadhead these plants. They evidently self-clean and bloom continuously over the spring and summer with no deadheading whatsoever. In my zone, these plants are semi-evergreen. This means that although a portion of the plant remains green and vital over the winter, come very early spring, there’s always alot of dead stuff to prune back. At that time, I prune mine all the way down to the healthy “core” of foliage towards the base of the plant. Within a few weeks of this pruning, the plant has bounced back, is generating new stems and foliage, and has begun setting buds.
Companion planting. My Blue Lines grow next to a True Blue border gentian (for a concentration of blue color) amid a drift of white: Spanish whitebells before them in the very front border, and white garden phlox behind them. These all make excellent companions for the Blue Lines in terms of aesthetics and common, necessary growing conditions.
This Fiskars SoftGrip Bypass Pruner is my choice for pruning/deadheading/cutting back every one of the perennials on this list, plus virtually every perennial I’ve got in my garden. It’s got more than enough power, and it’s incredibly sharp and beautifully machined. It’s absolutely perfect for making precise and delicate deadheading cuts and removing compromised foliage with surgical precision. Want to snip off some beautiful blue garden blooms and put them in a vase? Here’s your tool. I’ve got several different sets of Fiskars garden cutting implements in my arsenal. I love these tools. Order yours here, from Amazon, by clicking the #advertisement link.
7. Aurora Blue Delphinium (Delphinium elatum ‘Aurora Blue’)
The basics.
Height – 36″-48″. Spread – 24″. Light – full sun. Bloom color – bright, pure blue. Bloom time – early summer to mid summer, and again in late summer/early fall. Foliage – deep green, herbaceous. Hardiness – hardy in zones 3 – 9. Growth rate – medium. Pollinators – butterflies and bees. Bonus: one of the very hardiest and longest lived delphiniums. This plant can withstand a wide range of temperature extremes, is incredibly robust, and can live for more than 10 years. And the massive flower spires, comprised of the brightest blue semi-double flowers, are among the world’s most beautiful blue garden blooms. This is one badass of a delphinium.
Notes from the field.
I’ve got two of these plants growing in my big blue and white hill planting feature. I would have had three, but I inadvertently killed one by accidentally digging it up in the late winter/early spring of this year. I planted one of my remaining two Aurora Blues in the spring of 2021 as a healthy first year individual from a 12″ pot. The second one was planted this most recent spring as barely more than a bareroot. It came in a 3″ pot, and was definitely more root than anything else. Despite its inauspicious start, it has grown substantially in its first year, and will more than likely flower next summer. The more mature, and larger of my two delphs grew huge and flowered profusely this summer. Although these plants (in spite of their robust nature) require staking due to the massive size and heft of those bright blue flower spires, I did not stake mine. This unfortunate state of plant neglect arose as a result of my run-in with a detached retina. In any event, the delphinium was not staked as it should have been, nor was its neighbor, an adjacent Annabelle hydrangea, pruned as it should have been. The delphinium, at this point, resorted to a growth path parallel to the ground, with a phototropic skyward cant to the flower stems. It was incredibly beautiful, even though it was literally growing sideways. I can’t wait to see how gorgeous these Aurora Blues will be when they’re properly staked next year, and the bushy hydrangeas which grow next to them are properly pruned. The upshot here is that both of my Aurora Blues – the beefy second year plant and the newbie – grew in predictably healthy fashion. The flowers of the second year plant cemented the Aurora Blue delphs’ designation as one of my top 10 beautiful blue garden blooms.
Suggestions for planting Aurora Blue delphiniums.
Plant them as soon as you get them. I had excellent luck planting my Aurora blues in the spring. I’ve noticed that they are generally unavailable from either local nurseries or online sources past mid/late spring. Although these are very robust plants, avoid burying their root crowns too deeply and pushing too much moisture-retaining mulch against their stems. This is important in avoiding crown and stem rot. Mine were planted in locations near the very top of my blue and white hill, in full sun, in what would equate to a back border. Back of the planter locations are suitable due to the height of these plants.
Soil. These plants like a moist soil tht is well-drained. Mine are planted in my garden’s ubiquitous potting soil. The more immature of my two delphs did not receive any feeding beyond the slow-release fertilizer in the potting soil. The bigger, older plant has been fertilized twice this year with Espoma Plant-tone and will receive one more light topical application this fall. These plants are evidently not too fussy about soil pH. The soil of one of my delphs measures slightly acidic, while the other grows in neutral-to-slightly-alkaline soil (said alkalinity probably arising as a result of the delph’s proximity to plants which were treated with an application of garden lime).
Water. As is generally the case with all new transplants, new additions will require more frequent watering until they are established. These delphiniums appreciate regular watering as established plants, but are also fairly drought-tolerant. Do not waterlog these plants – continuously soggy soil will cause root, crown, and stem rot which, in turn, will kill them.
Pruning and/or deadheading. It would be reasonable to assume that deadheading these plants after their early/mid summer blooming is complete is beneficial, and would contribute to a second, less profuse blooming in late summer/early fall. I can tell you, unequivocally, that I did not deadhead my more mature, floriferous Aurora Blue this summer. And, in spite of this fact, it did indeed bloom again this late summer/early fall. Admittedly, this repeat blooming was not as profuse as the first. But it did occur, and it did so without the benefit of deadheading. I’ll say it again – I can’t wait to see these guys next year, when I really treat ’em right.
Companion planting. My Aurora Blue delphiniums, because of their height, grow near the top of the hill upon which they’re planted. Their immediate neighbors are large hydrangeas, planted behind them, which can surpass them in height. Around and in front of them are white garden phlox, and in the case of one of the more mature of the two delphiniums, my Takion Blue bellflowers. Basically, it’s like this: taller plants behind, and slightly shorter plants to the sides and front.
8. Grace Ward Lithodora (Lithodora diffusa ‘Grace Ward’)
The basics.
Height – 4″-11″. Spread – up to 48″. Light – full sun to partial shade. Bloom color – clear, deep blue. Bloom time – late spring into mid summer. Foliage – dark green, evergreen/semi-evergreen. Hardiness – hardy in zones 6 – 8. Growth rate – slow. Pollinators – butterflies and moths. Bonus: one of the truest and most beautiful blue garden blooms available. This little groundcover slowly spreads to cover an area of up to 4′ in diameter with deep green foliage and jewel-like blue flowers. Spills over retaining walls or down the sides of hills.
Notes from the field.
I planted my sole Grace Ward lithodora in May of 2021. I situated it on the north side of my blue and white hill planting feature in its outermost tier and in its sunniest location. The little plant grew very slowly its first year, and a good portion of it died and was pruned back in late winter/early spring of this year. It reponded beautifully to the pruning and slowly continued its outward spread, while flowering beautifully in late spring through mid summer. It grows beautifully in its location on the hill, creeping beneath and around taller plants, and mingling with its white flowering groundcover neighbor, Snow-in-Summer. As this plant further establishes itself, I’m looking forward to its ever-expanding blanketing of dark green leaves and starry blue flowers. I’ve yet to see another plant flowering this close to the ground that is as visually arresting as the Grace Ward. Its beautiful blue blooms are just as striking and attention-grabbing as those of any of the tallest blue bloomers in my garden.
Suggestions for planting Grace Ward lithodora.
Plant them as soon as you get them. I had great luck planting mine in spring at the end of May of last year. Since these plants are hardy only down to zone 6, I wouldn’t test them by planting them in the late fall. Spring or summer makes the most sense to me. Because of its low height and sprawling growth habit, the Grace Ward lithodora makes for a perfect rock garden occupant, draping down the side of a rock wall or scrambling over and between large stones. Mine grows down the side of the hill on which it’s planted, covering the slope in its foliage and flowers. This is really an amazing groundcover.
Soil. This plant likes slightly acidic to neutral soils that are well-drained.
Water. My Grace Ward was watered regularly when it was first planted. Once it was established, it required less frequent watering. This plant is definitely drought-tolerant.
Pruning and/or deadheading. Negative on the deadheading. I’ve successfully pruned back dead and dying stems and foliage in order to encourage new growth.
Companion planting. My Grace Ward grows around and beneath taller plants such as shasta daisies, True Blue border gentians and white garden phlox. As mentioned, it grows amicably with Snow-in-Summer, another groundcover, on the sunny North slope of the blue and white hill.
9. Hardy Plumbago (Ceratostigma plumbaginoides)
The basics.
Height – 4”-12”. Spread – 12″-24″. Light – partial shade to full sun. Bloom color – vibrant blue. Bloom time – mid summer to early fall. Foliage – rich green (turning reddish in mid to late fall), herbaceous. Hardiness – hardy in zones 5-9. Growth rate – medium. Primary method of growth/spreading/colonizing/naturalizing – rhizomes (rhizomatous). Pollinators – butterflies, moths, bees, and the occasional fly.
Notes from the field.
My hardy plumbago have been growing in my garden since the early summer of 2020. I originally planted eight individuals, but their rhizomatous spreading has resulted in a higher, unknown number. They occupy a patch of garden that ranges in light exposure from mostly shade to partial sun. All individuals grow well in either condition, but the plants which receive the most sun seem to flower just slightly more profusely. These are aggressive spreaders that can overwhelm smaller plants, so some pruning/dividing may be necessary. They don’t spread super quickly, but they are inexorable. My initial population of eight has, as explained, expanded to a much larger, indistinct number. The rhizomatous growth habit of these plants takes them where they’d like to be. In any case, they’re relatively easy to manage, and the beauty they bring to their sections of my big blue and white planting feature makes any minor disciplining more than worthwhile. These are incredibly hardy, extremely low maintenance groundcover plants. I love my hardy plumbago. One item to note – they are a bit slow to emerge and leaf out in spring. Be prepared for a bare patch of ground from winter through mid spring. By late spring, they’ll have emerged and begun to leaf out. Probably their most remarkable feature is their profuse, deep, vibrant blue flowering. My plumbago grow in a fairly shady part of the garden, and their beautiful blue blooms seem to glow in the dim light. Plumbago flowers offer among the very bluest of blues in the plant world. (This, and the final plant on this list were featured in an earlier article here about groundcovers. Please click here to read that article.)
Suggestions for planting hardy plumbago.
Plant them as soon as you get them. Early summer is the perfect time. This gives them the opportunity to settle in and get ready to bloom for you. I planted mine two years ago in mid summer as second year, field grown plants. They almost immediately set buds and flowered by the end of August.
Soil. These plants do well in a variety of soil types as long as long as it is well-drained. Mine are not fussy about soil pH. At various times, the soil in which they’re growing has ranged from mildly acidic to mildly alkaline, and they grew and bloomed beautifully. I do apply a feeding of Espoma Plant-tone to their spot in the planting bed in early spring.
Water. Water these guys once or twice a week while they’re establishing. After that, they’re incredibly drought-tolerant.
Pruning and/or deadheading. No deadheading at all. These are self-cleaners. A flower drops off and a new one takes its place with no help from me at all. In late fall or early winter, after all the foliage is brown and shriveled, or has fallen off, I cut the stems flush with the ground.
Companion planting. Hardy plumbago compliment taller plants beautifully (and smaller ones, too, if managed properly) and provide terrific later season color. They look great planted in front of, and among, my taller plants like garden phlox, liatris, and hydrangea. They mingle well with woodland forget-me-nots. and they provide a taller backdrop for my primroses which grow in front of them in the outermost border of the blue and white hill.
10. Woodland Forget-Me-Not (Myosotis sylvatica)
The basics.
Height – 6″-12″. Spread – 8″- 12″. Light – partial shade to full shade. Bloom color – periwinkle, or sky blue. Bloom time – April through May. Foliage – evergreen. Hardiness – hardy in zones 3-8. Growth rate – fast. Primary method of growth/spreading/colonizing/naturalizing – profuse self-sowing. Pollinators – bees, butterflies, moths, plus ladybugs, spiders, and dragonflies
Notes from the field.
What would an article about beautiful blue garden blooms be without forget-me-nots? Although these particular beautiful blue garden blooms blanket my garden’s “Blue and White Hill” planting feature year after year in the spring, woodland forget-me-nots are actually not true perennials in the strictest sense of the word. They are actually short-lived perennials, or biennials, which grow from seed in their first year, and then mature, set buds, flower, seed heavily, and die in their second year. But because these plants do seed so incredibly profusely, they spread/colonize/naturalize successfully enough to remain a constant and growing presence, year after year, in the garden. The reality is, therefore, that these plants are effectively perennial. They do persist (as a colony) in the garden year after year, in ever-increasing numbers.
I first planted these in my garden in the summer of 2020. I purchased twelve tiny plants, each in a 2″ mini pot, from a local nursery. They grew moderately that first summer, remained evergreen all winter, and exploded with growth and substance in their second summer. They bloomed beautifully, self-sowed massively, and died. But before they died, the seedlings started growing. These seedlings were too numerous to count. All of the forget-me-nots that grew in my garden this spring and summer were those seedlings. And they grew from seedlings into bushy clumps of evergreen foliage sprinkled heavily with glimmering light blue, star-like flowers. The woodland forget-me-not show continued for another spring and summer, and it’s got a bigger cast now than ever. There are even more drifts of seedlings waiting to grow and bloom next spring. I now have a fully naturalized and permanent colony of woodland forget-me-nots in my garden. And I’m thrilled. This bunch offers waves of fabulous blue blooms and rich green foliage in the shadiest sections of the garden. The beautiful sky blue blooms of these plants shimmer and twinkle like a field of tiny garden stars. They are truly exquisite. They easily make this top 10 list, and they make it with honors.
Suggestions for planting woodland forget-me-nots.
Plant them when you get them. If you buy these plants from a nursery in spring, you’re more than likely getting plants which are growing in their second year. These will either be already blooming (a great retail selling point) or will be blooming soon. These will drop their flowers, self-sow, then die not terribly long after you plant them. Such is this plant’s normal life cycle. If you buy them from a nursery toward the middle of summer (as I did), you’re more than likely getting plants that are basically little more than seedlings. That’s ok. Buy them and plant them and water them. They’ll grow a bit bigger and stay green through the fall and winter. Then they’ll put on a huge show for you the following spring, and leave you with a whole new crop that summer. If you’ve got seeds, sow them directly into the ground any time before the weather starts to turn cold. Mid to late summer is a perfect time.
Soil. Woodland forget-me-nots like moist, well-drained soil that can range from slightly acidic to slightly alkaline (low sixes to high sevens). I’ve fertilized mine lightly with Espoma Plant-tone with excellent results.
Water. Although these plants like moist soil, they can’t tolerate soggy soil. Waterlogging their roots will kill them.
Pruning and/or deadheading. No pruning, and no deadheading (unless you want to collect seeds). Leave the seedheads in place if you want these plants to self-sow. When the mature plants die, I leave much of their aerial structures in place to decompose as compost. If they prevent seedlings from rooting or receiving water and light, I’ll remove them.
Companion planting. My colony of woodland forget-me-nots reaches beneath taller hellebores, shasta daisies, veronica, and hostas, and grows side-by-side with Biokovo hardy geraniums, hardy plumbago, and primroses. These neighbors are friendly, and the setting is charming.
The sun now sets on my garden and its beautiful blue blooms…
Finally. Right? (Richard, Jaynie… you didn’t realize what you’d gotten yourselves into.)
I know there was a lot of info here, and I appreciate the fact that all of you – not just Richard and Jaynie – checked in and had a look at this one. At least you got to see some pics of the erstwhile mysterious True Blue border gentian, and pick up a little practical info regarding its needs and wants. And you got to see and read about some of my garden’s other beautiful blue blooms, too. Maybe you’ll even want to grow some of these in your own gardens (if you don’t grow them already).
I’m now convinced that it was good that Richard had first gotten me to think about blue flowers, and the importance of writing about them. And although this was definitely a long one, and there was alot of info here, I feel fairly justified in my long-windedness. Because, I believe, the color blue in the natural world is very special. For a flower, which can make no sound, this color is offered as a modest, yet undeniable imperative. The blue of a bloom is its voice. Its call. It may very well be the best way that a flower can tell you all about its own wondrous nature. And I feel honored to think that I may have helped it do that very thing.
Cheers, and Happy Gardening!
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From now on when I say I’m so blue, it will mean that I’m in a great mood! All of the plants you wrote about were absolutely beautiful. So many wonderful shapes and shades of blue put a smile on my face. It makes all of us look forward to next year when all of those blooms will return.
Thank you, Kevin! Such wonderful thoughts and kind words! I do agree with you about those blue flowers – the shades of blue are perfectly mesmerizing! I’m glad they’ve made you happy and are encouraging thoughts of next spring and summer, and the sunshine and warm weather to come. As always, thanks again!
Great list! Well done! Thanks for sharing!
I must tell you that it’s quite an honor to receive such a lovely compliment from Iva Kate and Ivy Gate Florals! You are truly a master gardener, and I’m truly humbled, and again, honored by your compliment. Thank you so much!
How kind! A couple of these flowers were unfamiliar to me before I read your piece. And I have yet to successfully grow primroses! I just keep trying.
I’m pleasantly surprised and happy that I was able to introduce one or two new ones to you! I do love all of the plants on this particular list and have been very pleased with their performance in my garden. I’m fortunate to have had good luck with the primroses. They look a bit spent and tired over the hot summer months, but it’s as if I watch them literally regroup in the cooler fall weather, bide their time over the winter, and explode with foliage and blooms in the spring. I do highly recommend the ‘Belarina’ series of doubles. They are remarkably tough and productive. Thank you once again. I really am honored.
A successful writer is one who can keep my interest even in a field where I have little knowledge.
Congrats
Wow, Rick – thank you so much! What an incredibly kind comment! I truly appreciate your kind thoughts and words, and I’m so glad you found the article interesting. Perhaps we’ll make a gardener of you yet! Once again, many thanks!
Thank you for this amazing article!
“beautiful blue blooms”….. wow, a totally magically magnificent garden all dressed in blue, It made my heart skippe a few beats….. beautiful images and truly very informative…. A Devine Garden 💙🌺
Roxxy, you continue to amaze me with your kindness, and your artist’s appreciation of nature’s offerings. As always, your lovely thoughts, observations, and comments are appreciated more than words can say. Thank you once again!
Thank you for the great article regarding magical blue flowers. They are stunning in every garden.
I’m so glad you liked the article – thank you! And I do agree with you. There’s just something about blue flowers – they truly are magical and stunning in every way!
Blue flowers are my absolute favorite! John, I sent you an e-mail with photo re: an invasion by some very beautiful caterpillars that are devouring my parsley. I’m not disturbing them until I learn what they are. Could you possibly identify?
We have 69 acres in the Little Muskegon River and for the third year have been invaded by Gypsy Moths. I’m ruthless when it comes to getting rid of them but don’t want to harm what might be a beautiful butterfly or moth.
Give my love to Dee Dee!
I’m glad you like blue flowers, Mary – they really are wonderful – truly, any blue flower is wonderful, I think. Fabulous. Thank you for reading the piece and commenting here, and thank you for the email. I’ll check it out shortly. I’m unequivocally horrible at insect identification, but I’ve got a friend who’s a mycologist and a whiz at entomology. I’ll send her your pics and see what she thinks. Thanks once again for your interest and your thoughts.