Catmint bloom is like faded denim.

Cats prefer catnip. It makes better tea too. Catmint, Nepeta X faassenii, is prettier though. It sprawls over the ground to get about three feet wide, without getting more than two feet deep. Where well exposed, it may not get much deeper than one foot. The aromatic gray foliage is denser than that of related catnip. Its individual leaves are small and furrowed.

Bloom begins with warming spring weather, and continues until cooling autumn weather. Individual flowers are tiny, and suspended on small floral stems. They just happen to be very abundant. Warmth stimulates phases of exceptionally profuse bloom. Floral color is light or pale blue, like faded denim. Shearing to deadhead enhances profusion of bloom.

Catmint works well as a rustic border or a ground cover for small areas. Alternatively, the blue bloom can be a delightful component of mixed perennials, in beds, planters or pots. Deer generally ignore catmint. Bees most definitely do not. They swarm it! ‘Walker’s Low’ is the most popular cultivar. It may be all that is available in some regions. Catmint is sterile, so generates no seedlings.

Something Blue

Is periwinkle blue, or slightly purplish?

Blue must be unpopular with the more common of pollinators. After all, colorful flowers are designed to attract some sort of vector to exchange pollen. It seems that most pollinators like yellow. Red and pink (which is actually a tint of red) seem to be more appealing to hummingbirds. Butterflies seem to really like pink and orange. Many flowers that seem to be white actually use infrared to attract bees, or ultraviolet to attract nocturnal moths. Other white flowers rely on wind, which is not discriminating about color.

Of the primary (red, yellow and blue) and secondary (orange, green and purple) colors, the only color that is more uncommon than true blue is green. That is probably only because green flowers do not contrast much against green foliage, so would be harder to find. Many blue flowers, like thyme, lavender, blue potato bush and jacaranda, are closer to purple. Some blue and purple color is probably only incidental, and in conjunction with invisible (to humans) ultraviolet coloration or patterns.

Except for purplish blue jacaranda, there are no substantial trees to bloom blue. Empress tree is flashy, but is even more purplish. However, most ceanothus, including a few that can grow as small trees, are famous for their clear blue bloom. Plumbago, blue hibiscus, echium and rosemary are blue blooming shrubbery. Creeping rosemary is a nice groundcover. Hydrangea has the potential to bloom blue, but often turns purplish or pink because of soil alkalinity. Lilac and wisteria vine can be lavender, pink or white, as well as ice blue.

There are several perennial and annual salvias and lupines that bloom blue. Russian sage, catmint, carpet bugle, campanula, perennial statice and lily-of-the-Nile are some of the other familiar perennials for blue flowers. Delphinium should probably be more familiar. Grape hyacinth and various iris bloom briefly but spectacularly with some of the richest shades of blue. Even though there are not many blue flowers to choose from, there is quite a bit of variety.

Annual statice, aster, zinnia, bachelor button, nierembergia, nigella, pincushion flower, forget-me-not and cineraria are uncommon annuals that are enjoyed by those who crave blue. Petunia happens to be one of the most popular of warm season annuals that also happens to produce some excellent blues. Later, brightly colored pansy and primrose can be just as flashy as popular cool season annuals.


Lithodora has more names than colors.

Both the common and botanical names of lithodora are variable. Many know it as purple gromwell. The botanical name can be either Lithodora diffusa or Glandora diffusa. Many of the cultivars lack their species name after one of these two genus names. There might be less variety with the cultivars than with the names! Floral color is the primary variable. 

White blooming ‘Alba’ is uncommon. After all, lithodora is popular for its rich blue bloom, which ranges from light sky blue to indigo. As the name implies, ‘Blue Star’ flowers have a white edge around a blue center. ‘White Star’ flowers have blue around white. Flowers are tiny but profuse in sunny situations. The dense evergreen leaves are likewise small.

Mature plants are generally only a few inches deep and perhaps two feet wide. They can eventually get more than six feet wide by rooting as they migrate. Although they grow too slowly for large scale ground cover, they work nicely in a sunny atrium, around boulders, or with mixed perennials. Lithodora is susceptible to rot in pots or if watered to frequently.


Few blooms are this blue.

There are not many flowers as blue as those of plumbago, Ceratostigma plumbaginoides. Individual flowers are not much more than half an inch long, but can be quite abundant until autumn. Each of the many terminal flower clusters is on a rather reliable schedule, so that new flowers begin to open as older flowers begin to fade.

Thin stems stand only about half a foot to a foot above underground rhizomes. Individual plants get about 3-feet wide, but realistically, will slowly spread farther if conditions are right. They do not spread fast enough to be invasive, but can get into some unexpected spots if not controlled. The simple leaves are about two inches long.

The main problem with plumbago is that it is deciduous, so it dies back to the ground in autumn. The weather is too mild here to produce the good fall color seen where autumns are cooler. Plumbago is a popular bulb cover because new growth, although slow to develop, emerges just in time to obscure fading foliage of early spring bulbs like daffodil and tulip.

Plumbago also works well with stone, since the stone is still appealing without the foliage through winter. The wiry stems weave nicely through otherwise bare cobbles, or spill slightly over low stone walls. Even though shade inhibits bloom, plumbago makes a nice informal ground cover under open shrubbery.

Lily Of The Nile

Agapanthus bloom looks like Independence Day.

It is no lily, but it does live on the banks of the Nile River. Lily of the Nile, Agapanthus africanus, endures both long dry summers and winter flooding. While inundated, it clings to the silty soil with a sturdy network of rubbery roots. Densely mounding foliage regenerates as floodwater recedes. If conditions get exceptionally warm and dry, foliage may eventually shrivel after midsummer bloom.

Home gardens are certainly more hospitable than the floodplains of the Nile River. The luxuriant foliage of lily of the Nile is evergreen locally, even if irrigation is minimal. The rubbery leaves get as long as two feet, arching outward from basal rosettes. New foliage obscures deteriorating old foliage. Plants that get too congested to bloom well might benefit from division of individual rosettes.

Lily of the Nile blooms around Independence Day, with round floral trusses that resemble exploding fireworks. Each blue or white bloom stands about two to four feet high, on slim and bare stems. Individual florets are small and tubular. ‘Storm Cloud’ blooms with darker blue or purple. Agapanthus orientalis may exhibit bigger blooms and coarser foliage. ‘Peter Pan’ stays low and compact.

Fourth of July

Lily of the Nile are floral Fourth of July fireworks.

Fireworks, Fourth of July parades, and the associated crowds are of course canceled for this year.

Lily of the Nile does not mind. It blooms in time for the Fourth of July regardless of what the rest of us are doing, or not doing. That is one of the two reasons why some of us know it as the ‘Fourth of July flower’. The other reason is that the nearly spherical floral trusses resemble exploding skyrocket fireworks. They are mostly blue, with some white. All that is missing is red.

The bloom in this picture is not exactly exemplary. It would have been larger, rounder, and likely more advanced in bloom if it had developed in a sunnier location. There are enough of them that we do not notice that most are somewhat diminutive. In autumn, many of the overgrown plants will be relocated to a sunnier situation where they can bloom as they would prefer too.

Lily of the Nile was the first perennial that I grew a significant quantity of. While in junior high school, a neighbor instructed me to remove a healthy colony of lily of the Nile that had grown obtrusively large in only twenty years. I could not just discard it, so chopped it into more than sixty pups, and planted it all over the neighborhood. Much of it is still there. A bit of it is here.

Back then, it was known as Agapanthus orientalis. In school, I learned it as Agapanthus africanus. I still do not know if they are two different species, or if one is just a variety of the other. I do know that mine are distinctly different from common sorts, with bigger and rounder floral trusses. The others have straighter stems that support their blooms batter, and finer foliage.


Blue like this is worth remembering.

Alaska, the biggest state in America, claims one of the most diminutive state flowers; their native alpine forget-me-not, Myosotis alpestris. Common woodland forget-me-not, Myosotis sylvatica, is the more familiar species here. It is not as common as the name implies though. Where naturalized, it stays within riparian or coastal situations, where the soil does not stay too dry for too long.

Forget-me-not is not notably popular in home gardens nowadays either. Of course, that only means that it is not often planted intentionally. Like violets and alyssum, it can proliferate where it gets a bit of water. Those who recognize it as more than a weed often leave it to provide delightful sky blue bloom until it succumbs to the warmth of summer. It is pleased to toss seed for the next year.

Common woodland forget-me-not is an annual, or at most, a biennial. Self sown seed starts to germinate through autumn, and grows into plants that can bloom before the end of winter. Manually sown seed wants to be in the garden early too, even if it grows slowly. New plants are too delicate to be commonly available in nurseries. Mature plants are less than a foot tall and two feet broad.

Blue Is The Loneliest Color

Colorado has a blue State Flower.

The majority of common pollinators are not impressed with blue. Otherwise, more flowers would be blue. After all, floral color appeals to pollinators. Each type of pollinator prefers specific colors. Plants customize their floral color to their preferred pollinators. If more flowers could attract more pollinators with blue, they would do so. Instead, they rely on colors that have worked well for them.

Green is actually the most common floral color. It is not obviously common because green flowers are generally ignored. They are the sort that rely on wind for pollination, so make little or no effort to draw attention. They are also the sort that produce the most and worst pollen, which gets carried farthest by the wind. Flowers that rely on pollinators produce coarser pollen that clings to things.

Of the many other colors that appeal to pollinators, most are significantly more complex than they appear. For example, what appears to be simple orange may appeal to pollinators that perceive it to be yellow, as well as those that are drawn to red, even if none are interested in orange. Different pollinators perceive different color ranges. Insects do not perceive red; but hummingbirds do.

That certainly could not explain why blue is such an uncommon color for flowers. It surely has more of a following than red, which is more common among flowers. Since most pollinators perceive blue, more flowers should utilize it. They could even add some ultraviolet or infrared to it, if that would make it more appealing. Nonetheless, true blue, without the influence of purple, is quite rare.

Lily-of-the-Nile and blue dawn flower are some of the more substantial species that provide exquisitely blue bloom. A few cultivars of butterfly bush bloom true blue too, but the color is not so clear and bright. Delphinium, bellflower, squill and grape hyacinth are smaller, but worthy perennials for the richest blues. Petunias, lobelia, nigella, cornflower and columbine are blue blooming annuals.

Many iris, sage and lupine provide exquisitely true blue bloom as well.

Blue Marguerite

60907Most blue flowers are blushed with purple to some degree. Except for lily of the Nile, true blue flowers are quite uncommon. Even with their yellow centers, the tiny daisy flowers of blue marguerite, Felicia amelloides, seem to be too blue to be real. They are almost expected to fade to lavender. Bloom may not be as full as it was a month ago, but continues as long as the weather is warm.

Mature plants are usually less than a foot and a half tall, and not much wider, with a symmetrically rounded form. The branches are rather fragile, and can be broken by something as trivial as a clumsy cat. They really are not strong enough for bouncy dogs or children. Yet, their tiny oval leaves are just raspy enough to deter deer. Unfortunately, blue marguerite plants live only a few years.



When first created by Chrysler, the Imperial was considered to be so close to perfection that fancy colors were unnecessary. It was originally only available in black or white, and later red, like the Chrysler Imperial rose that was named for it. It took a while for other colors to become available. Perhaps perfection is the same reason why nierembergia is only blue or white, or maybe purple.

Nierembergia is most popularly grown as a warm season annual for color from the middle of summer to autumn. It can get half a foot high and a foot wide. As a perennial, it has the potential to get twice as high and wide after its first year, but it lasts only a few years, and looks rather shabby through cool winter weather. The small flowers are evenly dispersed over the finely textured foliage, lacking only on the shaded sides of the densely rounded plants.

Because it gets a bit deeper than most other annuals, nierembergia is a nice transitional plant between lower annuals that might cascade over the edge of a planter in front, and higher or more upright perennials or shrubbery that might obscure a foundation behind. It can work alone too, but does not cascade from planters, big pots or hanging baskets.