Seeking the True Blue Flower

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Blue is one of the rarest of floral colors; only black is more elusive. And that’s probably because of the complex chemistry involved in producing a blue pigment, because bees, butterflies and other pollinators actually find blue quite attractive and easily visit blue flowers. That means that, evolutionarily speaking, blue flowers should be a good choice for blooms and flowers ought to have evolved as readily in that direction as they did towards the pink, white and yellow flowers that are so common.

But it turns out blue is hard to produce. The blue in flowers comes from a pigment that normally gives red or purple hues: anthocyanin (from Greek meaning dark blue). Various forms of it as well as related chemicals give flowers their blue coloration. But most plants with reasonable quantities of this compound produce purple to red flowers instead. Why?

Well, that’s complicated. Suffice it to say that various molecules and metal ions have to be present and also the environment near the pigment cells has to be alkaline. Many plants with true-blue flowers (notably in the families Boraginaceae and Convolvulaceae) have pink buds that turn blue as their environment becomes more alkaline, but most anthocyanin-rich flowers have acid sap and therefore their flowers turn out purple or red. In flowers, blue is a co-pigementation: it needs the right conditions to express itself.

Blue Flowers Are Highly Desirable

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These orchids have been dyed blue. Photo: Tangopaso, Wikimedia Commons

Blue flowers are much appreciated in the florist industry, so much so that dyeing or spraying white flowers blue to make them more saleable is a common practice. Dyes are even injected into living plants to give a blue tint to their flowers. That’s the case of the blue orchids that are so often seen on the market these days. They are actually blue-tinted Phalaenopsis and the next time they bloom, the flowers will be white.

There are scientists all over the world working to introduce genes for blue coloration into popular cut flowers—roses, carnations, chrysanthemums, etc.—with, so far, only mitigated success.

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The Applause rose has “blue genes”, but looks dark lavender to me! Photo: Blue Rose Man, Wikimedia Commons

The efforts to create a blue rose (Rosa) by transferring genes from blue-flowering plants into hybrid tea roses have resulted in a so-called blue rose, Applause, launched by Suntory in 2009 … but in my opinion, it’s not really blue. It’s closer to lavender. Of course, that is an exciting new color for roses, but the true blue rose has yet to be created.

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To me, these “blue carnations” from the Mooncarnation series are violet. Photo: Pagemoral, Wikimedia Commons

The same played out for carnations (Dianthus caryophyllus). Scientists transferred genetic material from blue-flowered plants, plus deleted carnation genes that were hindering the coloration. The resulting “blue” carnations (all those that I know of belong to the series Mooncarnation) are actually different shades of purple and violet. Now, these are new colors for carnations, of course, but they certainly aren’t blue.

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Newly introduced, this “blue chrysanthemum” is not yet commercially available. It’s closer to blue than blue roses and blue carnations, but still, it doesn’t look quite blue to me.  Photo: Naonobu Noda/NARO

Very recently (July 26, 2017), scientists announced the creation of the first blue chrysanthemum (Chrysanthemum x morifolium). It was obtained by inserting genes from a bellflower (Campanula medium) and a blue pea (Clitoria ternatea) into a chrysanthemum. Again, these new mums are being touted as true blue, but I still see a lot of lavender in the flowers and would definitely not call them blue.

Note that these manipulations are all examples of genetic engineering. In other words, these plants are GMOs, a term that scares the s___ out of many people. That said, blue roses and blue carnations have been on the cut flower market for a decade now and I have yet to hear any outcry.

True Blue Blossoms

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Ipomoea tricolor ‘Heavenly Blue’: now that’s a blue flower! Photo: Russel E, Wikimedia Commons

Obviously, there are true blue flowers, and in fact they evolved all on their own and have been around for millions of years. I don’t think anyone will deny that a ‘Heavenly Blue’ morning glory (Ipomoea tricolor ‘Heavenly Blue’) is blue. Moreover, this cultivar was not developed in a laboratory nor is it even a hybrid. Instead, it’s a selection of the wild I. tricolor, a species with naturally blue flowers.

And that’s just one example among many … well, among “quite a few.” There are probably no more than a few hundred true-blue flowers among the some 400,000 plants on this planet.

How to define “blue”?

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Bluebells (here, Campanula cochleariifolia), are not really blue, but violet. Photo: Jerzy Opiola, Wikimedia Commons

In horticulture, there is a long tradition of claiming any flower even the slightest bit close to blue as being a blue flower. Above all, violet-blue flowers—definitely more violet than blue!—are universally called “blue” and violet is an abundant color in the floral world. I’ve always felt this was a case of wishful thinking: we’d like to have blue blooms, so we accept anything close to blue as being true blue.

This seems to be a worldwide phenomenon, by the way: in all the languages I know (4), purple flowers are regularly called blue. Linnaeus himself, the father of botany, named many violet-colored flowers coerulea, which means blue.

Also, I suspect the definition of blue varies from one individual to another. As I researched this article, I realized that I take a rather narrow view to “true blue”. I tend to apply that term to lighter blues (cyan, azure, sky blue, etc.), while to my eye, shades that could be considered blue (indigo, cobalt, etc.) are violet. I’m not sure everyone would agree!

Obviously, we could take the scientific definition of blue as a benchmark. Blue is caused by light rays ranging from 450 to 500 nanometers … but who has a device capable of measuring that?

True Blue Flowers

Here are some flowers that, in my eyes, are true blue. I’ll admit it’s a subjective choice, but—hey! —I am the one writing this article!

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Allium caeruleum. Photo: col&tasha, Flickr

  1. Allium caeruleum (blue globe onion) – bulb, zone 3
  2. Amsonia spp. (bluestar) – perennial, zone 4 to 6, according to species
  3. Anagallis arvensis (poor man’s weather-glass) – annual

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    Borago officinalis. Photo: Sten Porse, Wikimedia Commons

  4. Borago officinalis (borage) – annual herb
  5. Brunnera macrophylla (Siberian bugloss) – perennial, zone 3
  6. Centaurea cyanea (cornflower, bachelor’s button) – annual
  7. Ceratostigma plumbaginoides (leadwort) – perennial, zone 6
  8. Clitoria ternatea (blue pea) – tropical climber, annual
  9. Commelina communis (dayflower) – annual weed

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    Corydalis flexuosa. Photo: jardinierparesseux.com

  10. Corydalis flexuosa (blue corydalis) – perennial, zone 6
  11. Cynoglossum amabile (Chinese forget-me-not) – annual
  12. Eryngium spp. (sea holly) – perennial, zone 4
  13. Evolvulus x ‘Blue Daze’ (compact morning glory) – annual
  14. Hydrangea macrocarpa (blue hydrangea), blue in acid soils – shrub, zone 6
  15. Ipomoea tricolor ‘Heavenly Blue’ (morning glory)—annual climber
  16. Linum perenne (perennial flax)—perennial, zone 3
  17. Linum usitatissimum (common flax) – annual

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    Meconopsis betonicifolia. Photo: Andrew Curtis, Wikimedia Commons

  18. Meconopsis betonicifolia (blue poppy) – biennial or short-lived perennial, zone 3
  19. Mertensia spp. (Virginia bluebells and others) – perennial, zone 4
  20. Myosotis spp. (forget-me-not) – biennial, zone 3
  21. Oxypetalum caeruleum (tweedia) – annual
  22. Plumbago auriculata (blue plumbago) – tropical climber or houseplant

Flowers That Are Often Blue

The following plants come in a wider range of colors, including many violets and purples, but also some true blues. With these variable plants, if you want blue flowers, make sure you pick the right cultivar.

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Delphinium ‘Blue Fountains’: this mix from seed contains blue flowers, but also purple and white blooms. Photo: J.W. Jung Seed Co.

  1. Delphinium spp. (delphinium, larkspur) – perennial or annual, zone 2
  2. Gentiana spp. (gentian) – perennial, zone 2 to 6, according to species
  3. Eustoma grandiflorum (lisianthus) – annual
  4. Hyacinthus orientalis (hyacinth) – bulb, zone 4
  5. Iris x germanica (bearded iris, garden iris) – perennial, zone 3
  6. Lobelia erinus (edging lobelia) – annual
  7. Lupinus spp. (lupine) – annual or perennial, zone 3
  8. Muscari spp. (grape hyacinth) – bulb, zone 3
  9. Salvia guaranitica (blue anise sage) – annual in cold climates
  10. Salvia patens (gentian sage) – annual in cold climates
  11. Viola x wittrockiana (pensée) – biennial or short-lived perennial, zone 4

So-Called Blue Flowers

What follows is just a short list of plants many gardeners consider to have blue flowers, but that, personally, I find too close to violet to belong in that group. So if you’re planning a blue border, you might want to skip these.

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Ageratum houstonianum ‘Blue Hawaii’: a pretty shade of violet, but not blue. Photo: Swallowtail Garden Seeds

  1. Aconitum spp. (aconite, monkshood) – perennial, zone 3
  2. Agapanthus spp. (lily of the Nile) – summer bulb or perennial, zone 7
  3. Ageratum houstonianum (flossflower) – annual
  4. Anchusa spp. (bugloss) – biennial or perennial, zone 3
  5. Aquilegia coerulea (blue columbine) – perennial, zone 3
  6. Browallia spp. (browallia, amethyst flower) – annual
  7. Campanula spp. (bellflower) – biennial or perennial, zone 3
  8. Echinops spp. (globe thistle) – perennial, zone 3
  9. Geranium spp. (hardy geranium) – perennial, zones 2 to 9, by species
  10. Hyacinthoides non-scripta (bluebells) – bulb, zone 4
  11. Iris sibirica (Siberian iris) – perennial, zone 3
  12. Iris versicolor (larger blue flag iris) – perennial, zone 3
  13. Lobelia siphilitica (great blue lobelia) – perennial, zone 3
  14. Scilla siberica (Siberian squill) – bulb, zone 320170829A
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Start Early: Sow Your Pansies Now!

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Pansy ‘Cool Wave Blueberry Swirl’. Photo:  BallSeed

Did you know you can sow your pansies (Viola x wittrockiana) for next year’s garden now, that is, at the end of July or in August?

Surprising, I know, but think of it this way. Pansies are not really annuals, but rather biennials or short-lived perennials (they rarely live more than 3 years) hardy to zone 4 or even 3. If sown in late summer, in the ground or in pots, that will give you seedlings you can transplant to their final location in October … and that will be ready to bloom as soon as the snow melts next spring.

One less task to carry out during the busy spring period!

Sowing pansies is simple enough. Just trace a furrow or drill small individual holes about ¼ inch (6 mm) deep in rich, moist soil in the sun or partial shade. Sow the seeds, cover them with soil and water well. That’s all!

Afterwards, just water when the soil is dry and keep weeds away. The tiny plants will do the rest!

2017: The Year of the Pansy

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Pensées (Viola x wittrockiana) ‘Majestic Giants Mix’. Photo National Garden Bureau

Each year the National Garden Bureau, a non-profit organization promoting the pleasures of home gardening, selects one bulb, one annual, one perennial and one edible plant to celebrate. It’s a great way to discover a new plant or to learn a bit more about a plant you may already be growing.

Here’s the second of 2017’s four plants, the annual we call the pansy.

Origin

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The Johnny-jump-up (Viola tricolor) is one of the ancestors of today’s pansy. Note the “whiskers”.

The garden pansy (Viola x wittrockiana) doesn’t exist in the wild. It’s a hybrid plant developed back in the 19th century, mostly from three Eurasian species of wild pansy: V. lutea, with yellow flowers, V. altaica, with violet flowers, and especially the well-known Johnny-jump-up most gardeners know, V. tricolor. The garden pansy differs from the wild species by its larger overall size and much larger flowers. However, if a garden pansy is allowed to self-sow, which it will do quite willingly, it tends to return fairly quickly to the appearance of a wild pansy.

As for the origin of the name pansy, it’s from French. Pensée simply means thought and the plant picked up this name because the flower of the wild pansy, which bends slightly downwards and bears whiskers (actually, nectar guides), was said to look like the face of a man lost in thought. With the adoption of the name pansy for thought, the flower became the symbol of remembrance and commemoration.

In the language of flowers, the pansy of course means “I’m thinking of you”!

Violet or Pansy?

Violets and pansies are close relatives and share the same generic name: Viola. But they belong to two different subgenera. So how do you tell the two apart?

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Violet: 2 upper petals, 3 lower petals.

Violets (Viola subgenus viola) have flowers composed of 2 upper petals and 3 lower petals. The flowers are usually small, with the upper petals leaning backwards, and they mainly bloom in the spring. The leaves are often heart-shaped, although they may also be lobed.

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Pansy: 4 upper petals, 1 lower petal.

Pansies (Viola subgenus Melanium) have flowers with 4 upper petals and only one lower petal. The flower appears flattened, with all the petals on the same plane. They’re much longer blooming than violets. Indeed, many pansies flower from spring to late fall. Finally, their leaves are smaller with crenate margins.

Pansy or Viola?

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Viola (at left), pansy (at right).

Here things get more complicated. The small-flowered plants gardeners call violas are definitely on the pansy side of the pansy/violet divide (i.e. they belong to the subgenus Melanium). The term “viola” was adopted to distinguish smaller-flowering pansies from larger-flowered garden pansies. Also, since many violas are the result of crosses with alpine species, they tend to be hardier and longer-lived than garden pansies.

In general, then, if the plant has large flowers and is treated as an annual bedding plant, it’s a pansy, and if it has smaller flowers and is sold as a perennial, it’s a viola.

History of the Pansy

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This 1902 catalog shows that great-grandma’s pansies were already much like those of today.

It’s generally accepted that Lady Mary Elizabeth Bennet (1785-1861), daughter of the Earl of Tankerville, created, with the help of her gardener, William Richardson, the first garden pansies early in the 19th century. She had built up a collection of wild pansies of all possible colors and began making crosses to increase the choice. She first presented her hybrids in 1813 and they were immediately adopted by gardeners.

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Pansies with dark blotches were first launched by Lord Gambier in 1839. This one is however a modern variety: ‘Matrix Solar Flare’.

However, at about the same time, Lord John James Gambier, a British officer, was also working with wild pansies, and also with his gardener, William Thompson. He set out to give the flowers a fuller appearance by choosing to cross plants with broader petals that overlapped, resulting in the almost moon-shaped flower so typical of today’s pansy. In 1839, he also produced the first pansy that had blotches instead of whiskers, ‘Medora’, a characteristic that is still seen today.

Pansies have been popular garden plants since the mid 1800s and remain among the top three annuals grown in North America.

A Wide Variety

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Pansies come in a wide range of colours. Here ‘Nature’ mix. Photo National Garden Bureau.

Do you have a favorite color? Si so, you’ll surely find a pansy to match it. Few other flowers offer such a wide color range: purple, blue, white, pink, red, orange, yellow, green, even almost black. Pansies can be unicolor, bicolor, or tricolor, and bear blotches, whiskers, stripes or no markings at all… but they always have a small yellow eye. Some have wavy or fringed petals; others are fragrant.

Pansies are typically classified into 4 categories: large-flowered (3 to 4 inches/8 to 10 cm in diameter), medium-flowered (2 to 3 inches/5 to 8 cm in diameter), multiflora (flowers from 1 to 2 inches/2.5 to 5 cm in diameter), and the most recent category, trailing, that is, pansy plants that spread up to 2 feet (60 cm) in diameter. This latter are making pansies popular in hanging baskets.

Growing Pansies Hot or Cold

Though nurseries sell pansies as annuals, they’re actually short-lived perennials and will overwinter in fairly cold climates, down to hardiness zone 4.

Pansies actually do best under cool summers: they positively thrive in many parts of Scandinavia and Canada, for example.

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Pansies used in a winter display at Disneyland.

In regions with mild winters (zones 9 to 11), pansies are typically used as winter annuals. At Disney World in Florida and Disneyland in California, for example, gardeners use them abundantly in their displays from October through April, and then pull them out and replace them for the summer with annuals more resistant to the coming heat.

In temperate regions, though, most pansies are planted in spring for summer bloom. As they tolerate cold nights and even light frost, it’s best to plant them early, before the other summer annuals, about 3 or 4 weeks before the last frost date.

In the right climate, pansies will remain in bloom until temperatures drop to near freezing in late autumn. In regions with hot summers, though, their flowering typically slows down or stops in summer until cooler temperatures resume in the autumn. To avoid this, gardeners in hot-summer areas should plant pansies in partial shade rather than full sun and also mulch them well (mulch helps keep the soil cool).

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Pansies aren’t much bothered by cold or snow.

There are also extra-hardy pansies designed for fall planting, like the ‘Ice’, ‘Icicle’ and ‘Snow Angel’ series. The idea is to plant them early in the fall so they’ll bloom abundantly until it gets really cold (when soil temperatures dip below 45˚F/7˚C), then they stop for the winter and begin to bloom again in the spring when soil temperatures again reach 45˚F/7˚C, just about when narcissus and tulips come into bloom. These pansies are usually hardy to zone 4.

General Pansy Care

Pansies prefer a rich, moist, well-drained soil. Space them about 6 to 8 inches (15 to 20 cm) apart (18 inches/45 cm for trailing pansies). Water them regularly over the first two weeks so they settle in. As mentioned above, the use of mulch to keep the soil moist and fresh is highly recommended.

If you don’t pull out your pansies in the fall, you’ll discover most will survive the winter and bloom for a second year. They rarely bloom a third season, but often self-sow to a certain degree, providing flowers for several years. As mentioned above, self-sowing pansies tend to gradually return to the small-flowered wild form.

Pansies From Seed

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1914 pack of pansy seeds.

The vast majority of gardeners buy nursery-grown pansies in flats as bedding plants in the spring, but there is no reason you can’t grow them from seed.

Sow them indoors about 8 weeks before the average last frost date in a pot or tray of moist potting soil, covering the seeds very lightly with 1/8 inch (3 mm) of mix.

If possible, place the container in the refrigerator for 4 to 7 days, then after this cold treatment, move it to a fairly cool spot, about 65 to 70˚F (18 to 21˚C).

Pansies are unusual in that they germinate best in darkness. You can therefore put them in a basement or cupboard until they sprout. I just put the seed tray inside a black plastic garbage bag. As soon as you see small seedlings come up, usually after about 10 to 20 days, move to a spot where they get bright light.

Even after germination, though, pansy seedlings prefer cooler conditions than most other annual and vegetable seedlings: 65˚F (18˚C) or less. You could, for example, place them near an east window, in a cold frame or in an unheated greenhouse. Keep the soil moist.

As soon as the nights start to remain above 40˚F (5˚C), start to acclimatize your seedlings to outdoor conditions.

Finally, it is also possible to sow pansies directly in the garden… for next year’s bloom! Do so in June or July.

Fun Facts About Pansies

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Pansy flowers are edible: here, ‘Cool Wave Yellow’. Photo National Garden Bureau

  • Pansy flowers are edible. They can be eaten as is (they have a slightly minty taste) or you can make sugared pansies by coating them in egg white and dipping them in icing sugar.
  • Pansies have many common names including heartease, heart’s delight, tickle-my-fancy, Johnny-jump-up, Jack-jump-up-and-kiss-me, come-and-cuddle-me, three faces in a hood, monkey face, kiss-her-in-the-pantry, peeping Tom and love-in-idleness.
  • In general, yellow and blue pansies are the most fragrant. They are at their most highly scented in the morning.
  • The botanical name given to the garden pansy, x wittrockiana, honors Swedish botanist Veit Brecher Wittrock (1839-1914) who did a great deal of research on the genus Viola.
  • The Greeks used pansy flowers to make a love potion. William Shakespeare recalls this in A Midsummer Night’s Dream, Act II, Scene I, saying about heartsease (the pansy) that “the juice of it, on sleeping eyelids laid, will make a man or woman madly dote upon the next live creature that it sees.”
  • In days of yore, pansy syrup was used to treat venereal diseases.
  • Johnny-jump-ups (V.  tricolor), with their 3-colored flowers, were taken by early Christians as a symbol of the Holy Trinity.
  • In German, the pansy is called Stiefmütterchen (little stepmother). The fat lower petal represents the stepmother, the plump petals on each side are her own well-fed daughters and the two thin upper petals are the two neglected stepdaughters.

Now that you know so much more about pansies, I hope you’ll try your hand at growing these fabulous flowers this spring!