Columbine Species for Woodlands and Borders
(Editor's Note: This article was originally published on June 21, 2008. our comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
Last winter I wrote an article on "The Best of the Dwarf Columbines.". In that article is described those species that are generally under 30 cm, ideal subjects for alpine gardens and troughs or the front of the border. This companion article will cover the taller species, more suitable for the perennial border, wildflower or shade gardens. I should also note that there are plenty of taller columbine hybrids but that could be the topic of a future article!
There are about 65 species of columbines (Aquilegia) in the world, all native to temperate regions of the northern hemisphere. Many of the taller species inhabit meadows or open woodlands, with some extending into the alpine zone. In the garden, they are carefree plants that simply require well-drained soil and regular watering during dry spells. They are all late spring-early summer bloomers. Many of the species about to be described are not available at local nurseries, but are often found among offerings of mail-order specialist nurseries or as seed from seed exchanges. However, a word of warning; columbines are promiscuous and will hybridize with blooming neighbours so seeds from exchanges may end up being hybrids. If growing from seed, provide the sown seeds with a stratification period of 4-6 weeks to simulate a winter. All of these species are hardy to USDA zone 5 and several are hardy to zone 3.
Let's start with the most common and important species, at least from a gardeners perspective; A. vulgaris or the common European columbine. This species is the ancestor in many of today's modern hybrids. It is a very prolific and promiscuous species, self-seeding with abandon and crossing with other nearby columbines. If allowed to mature, these seedlings can show a myriad of colours and forms. The original wild form has blue flowers, but even in the European countryside, you can find these columbines in white, purple, wine-red or pink, with single and double flowers, with or without spurs. Plants can be variable in height, mostly between 45-70 cm.
Various colour forms of Aquilegia vulgaris
Scattered throughout Europe and western Asia are a host of other columbine species that look for all intents, like A. vulgaris. In fact, some authorities claim they are simply forms of the common columbine, rather than distinct species. Aquilegia atrata hails from the Alps and Apennines. It is not unlike a very dark purple-violet to chocolate-wine coloured A. vulgaris. Similar in appearance is the Carpathian native A. nigricans, but this species has somewhat sticky foliage. Aquilegia olympica hails from the Caucasus region and again looks for all intents like a blue-flowered vulgaris-type except the petals and sepals are a little wider.
Aquilegia alpina is native to the Alps and is a charming columbine which varies in height from dwarf 15 cm to upwards of 60 cm. Alas most of the A. alpina in the trade are hybrids with A. vulgaris. The true A. alpina has dark blue flowers whose spurs are straight or slightly incurved, never strongly hooked (if so, this will indicate the A. vulgaris genes). The stamens are inserted (i.e. do not exceed beyond the petals).
There are a few other taller European species but they are rarely seen in North America. Aquilegia einseleana looks like a larger version of A. bertolonii (described in my earlier article on dwarf columbines) with deep blue, straight-spurred flowers. Aquilegia thalictrifolia has similar flowers but the foliage is very much like Thalictrum and is slightly sticky. Aquilegia grata is a native of the Balkan region with reddish-violet, straight-spurred flowers. Most distinct is A. aurea, the only European species with yellow flowers. Plants sit on the fence between being dwarf or taller as they range from 25-40 cm in height. Their flowers are much like a yellow-flowered A. vulgaris.
The next group of columbines are those that hail from the Himalayas east through China, Japan and Siberia. Aquilegia buergeriana is a Japanese species which reaches 50-80 cm. The flowers come in two colour forms; primrose yellow or two-tone purple and yellow. The spurs are fairly straight and the stamens are inserted. The most popular selection is ‘Calimero', a lovely dwarf form described in my dwarf columbine article. Very similar, and once included with A. buergeriana, is A. oxysepala, a species that extends from Japan into eastern China and southeast Siberia. The flowers are two-toned purple and yellow but the spurs are strongly hooked.
The only tall, fragrant columbine is A. fragrans, a cream-coloured species from northern India. The spurs are relatively straight and the stamens are the same length as the petals. This species is not as hardy as most of the others, being rated for zone 6. Of similar colour is A. lactiflora, a rare species from central Asia whose spurs are mostly straight and stamens are exerted ( i.e. extend beyond the petals).
Looking like a dark purple-wine version of A. vulgaris are the central Asian species A. atrovinosa and A. kuhistanica, both with relatively short, strongly hooked spurs and inserted stamens. From the Altai region, northeast to Siberia, is A. siberica; a blue, white or two-toned vulgaris-type easily distinguished by its leafless flower stems. Finally, from western China comes A. rockii, a very tall species with smallish, reddish-purple flowers whose spurs are very short and straight, with inserted stamens.
Some Asian species include A. kuhistanica, A. atrovinosa and A. rockii
The last group are the North American native columbines. Aquilegia canadensis was described in the dwarf columbine article but this species is quite variable and some forms may reach 60 cm or more. The red and yellow flowers are a common woodland sight in eastern North America. In the west is the similar species, A. formosa, whose petals are more flaring than those of A. canadensis. The small-flowered Aquilegia micrantha is another western species with similar-shaped flowers but comes in cream, yellow, pink or blue. All of these species have straight or outward-flaring spurs and exerted stamens.
Among the most delicate columbines are A. canadensis and A. formosa
The northernmost columbine in North America is A. brevistyla, which extends into Alaska. This two-toned blue and white flowered species is one of the few American columbines with hooked spurs, a feature more prominent in Eurasian species. It is thought that A. brevistyla probably migrated into North America from Siberia quite recently, as most of the tall columbines in America are yellow or red with straight spurs and exerted stamens, ideally adapted to hummingbird pollination. Aquilegia brevistyla, with its blue flowers and inserted stamens are bee pollinated. Another western species is A. flavescens, a yellow-flowered species with short, straight spurs and exerted stamens (this one is visited primarily by hummers).
Widespread in western North America is A. flavescens and A. brevistyla
The ancestors of the long-spurred garden hybrid columbines are the western and southwestern US species A. chrysantha, A. longissima, A. chaplinei and A. coerulea. Aquilegia chaplinei is a dwarf version of A. chrysantha, described in the dwarf columbine article. Aquilegia coerulea can also be dwarf, but tall forms do exist. Its two-toned blue and white, long-spurred flowers are unmistakable. Aquilegia chrysantha is the classic long-spurred yellow columbine of SW USA. Aquilegia longissima is often considered a variety of it but is distinguished by its super long ( up to 15 cm!) spurs.
The long-spurred species include A. longissima, A. chrysantha and A. coerulea
This list of taller columbines is not exhaustive and you may come across other species listed in specialty seed catalogues or seed-exchanges. The multitude of hybrids are, of course, much appreciated in the garden, but there is a special charm exhibited by the wild species columbines.
I would like to thank the following people for the use of their pictures: poppysue for A. alpina and A. coerulea; Grasmussen for A. brevistyla