Camassia is one of the few garden-worthy bulbs to hail from North America. They are ideal for filling the gap between the spring-flowering bulbs and the beginning of the summer bulbs. To learn more about this small group of showy blue-flowered bulbs, continue reading!
(Editor's Note: this article was originally published on September 19, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
When we think of spring bulbs, most of us think of the Eurasian species of daffodils, tulips and crocus. Very few garden-worthy bulbs seem to originate from North America but there is at least one exception called quamash or camass lily, members of the genus Camassia. This genus has only 6 species. They are closely related to the Eurasian genera Ornithogalum (Star-of-Bethlehem) andScilla (squills). Blue is the predominant colour but white and pink forms of Camassia do exist, along with double-flowered selections. In the wild, they generally grow in sunny, moist meadows, thus they lend themselves beautifully to naturalizing in wildflower gardens and meadows. They bloom from mid-late spring to early summer, just after the last tulips. Most are hardy to zone 4.
In the garden, provide them with humus-rich, evenly moist soil. They will tolerate heavy clay soils and poor drainage. Full sun will develop the strongest-stemmed plants. Unlike many spring bulbs, Camassia do not need to ‘bake' in summer. While their foliage may disappear by mid-summer, their bulbs do not mind being kept moist during their dormant season. Camassia are perfect for utilizing in the perennial border where their summer-dying foliage can be hidden by their surrounding neighbors. They may even be used on the edges of garden ponds as long as their bulbs are above the water-table.
The name ‘quamash' is a word used by the Nez Perce, Cree and Blackfoot Tribes of the Pacific Northwest, who would gather and roast the bulbs as a food source. Specifically, they would eat the species Camassia quamash(aka C. esculenta). This was not without its risk as the poisonous death camass (Zigadenus spp.) often grew alongside quamash. It was important for young women in the tribe to learn how to distinguish between these two bulbous species. Quamash was also an important food source for the Lewis and Clark expeditions.
Camassia quamash is native throughout western North America. In the garden, C. quamash is among the smallest-sized Camassia (20-50 cm) and has rather floppy foliage compared to the other larger species. Their flowers are typically deep violet-blue. The cultivar ‘Orion' has steely-blue flowers while ‘Blue Melody' has variegated foliage. This species produces masses of smallish bulbs and benefits from division every few years.
Details of C. quamash
In central-eastern North America hails the wild hyacinth, C. scilloides. This species is similar in size to C. quamash but has smaller-sized blooms (they really do resemble Scilla). It is not widely-grown as a garden ornamental as the other species have much larger blooms. However, it does make an admirable wildflower for damp meadows. Their flowers are light to mid-blue. Very similar in appearance is C. angusta, a native of south-central USA. In areas where both C. scilloides and C. angusta grow together, C. angusta blooms a week or two later than C. scilloides.
Details of C. scilloides
The remaining three species are the giants among the Camassia and all hail from the west. Camassia cusickiiis native to Idaho and Oregon. This species is quite leafy compared to the others. The flower stems may exceed 100 cm with relatively large, icy-blue, star-like flowers. ‘Zwanenberg' has mid-blue flowers.
Details of C. cusickii
Camassia howellii is endemic to southwestern Oregon. This rare species is almost indistinguishable from the more common C. leichtlinii. It differs primarily in having smaller, shiny seed capsules and fewer seeds per capsule than its close relative. By far the most garden-worthy, at least in my opinion, is C. leichtlinii, a native of west coast North America, from California to southern British Columbia. This species is the most floriferous of the Camassia I grow. Plants produce tall, 100 cm plus, stiffly-upright stems that are ideal as a cutflower. The flowers are typically dark violet-blue but there are several named selections. ‘Blue Danube' is deep blue; ‘Electra' has super-sized blue flowers; ‘Alba' has white flowers; ‘Semiplena' and ‘Plena' have semi-double and double flowers respectively, which are creamy-white to pale yellow; ‘Magdalen' has light lavender-blue flowers while ‘Pink Form' is soft pink.
Examples of the various colour forms available among C. leichtlinii
Camassia are not as readily available as many of the other fall-planted bulbs but are well worth the search. They are excellent additions to the bulb garden for helping bridge the gap between the typical spring bulbs and the summer-flowering types.
I would like to thank buggycrazy (pink form of C. leichtlinii) and creekwalker (C. scilloides) for the use of their pictures.
About Todd Boland
I reside in St. John's, Newfoundland, Canada. I work as a research horticulturist at the Memorial University of Newfoundland Botanical Garden. I am one of the founding members of the Newfoundland Wildflower Society and the current chair of the Newfoundland Rock Garden Society. My garden is quite small but I pack it tight! Outdoors I grow mostly alpines, bulbs and ericaceous shrubs. Indoors, my passion is orchids. When not in the garden, I'm out bird watching, a hobby that has gotten me to some lovely parts of the world.