Everything you need to know about growing camassias

Camassias are tall, elegant and simple to grow. It’s easy to see why people fall in love with these American beauties, says Val Bourne.

If you see a haze of blue in May in a grassy meadow or on a woodland edge, it’s probably going to be starry-flowered camassias stretching up to Heaven. These American bulbs, once an important source of food for native North Americans, were officially discovered in 1806 by Capt Meriwether Lewis and William Clark, so they’re not merely beautiful.

Their tendency to flower later than most bulbs helps to fill the May gap and their ability to tolerate moister conditions than most bulbs means they can be grown in a greater variety of situations. They make a perfect entrée for a summer-flowering wildflower meadow and they’re an essential part of Highgrove’s four-acre meadow in The Prince of Wales’s Gloucestershire garden, rising above butter-cups and pre-empting wild orchids. Elegant, yet understated, camassias are also planted in long grass at Great Dixter in East Sussex.

The beautiful spring azure-blue camassia leichtlinii flowers.

Stella Exley, of Hare Spring Cottage in North Yorkshire, has developed a Plant Heritage Collection, having fallen under their spell almost 30 years ago.

‘We went to look at a house in south Devon, with a view to buying, and there was a haze of blue on the woodland edge,’ she recalls. ‘It was late April and that hue of blue mesmerised me. I’d never seen them before. I’d never heard of them, although I was into bulbs. Within days, I’d bought my first potfuls.’

Recommended videos for you

Stella’s passion soon turned into an obsession and her collection now contains five species and 80 named cultivars. Here are her tips for growing them.

How to grow camassias, by Stella Exley

  • Buy bulbs after August, so that you get this year’s crop rather than last year’s.
  • Plant camassia bulbs in moist soil during autumn at a depth of 8in or about double the size of the bulb. They’ll thrive in heavy clay or damp grass.
  • Deadhead after flowering, because seedlings will be variable.
  • Allow the foliage to die down before mowing.

Camassia quamash Orion.

  • Split camassias in July and August if your clump is congested.
  • The flowers are good for cutting, but falling petals can stain white tablecloths.
  • Plant a selection containing C. quamash, C. leichtlinii and C. cusickii, so that heights and flowering times vary. All three are equally easy to grow and can be planted in woodland or border. They can also be grown in containers, as long as they are watered.
  • Veronica germanica Tissington White makes a superb partner for camassias. Otherwise, plant them among dicentras, polygonatums and ferns.

Which camassias should I plant?

Camassias can give six weeks of interest from late spring until early summer, in a variety of blues and creamy whites, as long as you plant different species. C. cusickii, principally native to Oregon and Idaho in the US, is the earliest to flower and will coincide with late-flowering white narcissi, such as White Lady. The large bulbs produce broader foliage and ice-blue flowers on a shorter plant. Zwanenburg, selected by Michael Hoog of Van Tubergen in 1969, has wisteria-blue flowers. It’s a subtle blue, with a paler stripe down each petal, so when planted en masse it creates a soft sheen. It also has sumptuous green-tinted flower buds; the largest of any camassia.

The deepest-blue flowers belong to selected forms of C. quamash, a widely distributed species found in British Columbia and from Washington south to California and eastwards to Montana and Utah. Known as the common camas, this short species (reaching one foot in height) has bright-green, grassy foliage, making it perfect for naturalising in meadows. The starry flowers have bright-yellow stamens and there is a tendency for the bottom petal to point straight down in contrast to the other five, which form a radiating arc.

Stella rates Orion, a widely available selection made by Van Meeuwen sometime before 1913, because it can look almost indigo in certain lights. These ‘quamash’ cultivars tend to flower from late April through May and, if the weather stays cool, they may even last into June.

The great camas, C. leichtlinii, is the most widely grown in gardens and the most spectacular because it can reach more than 3ft high. It flowers two weeks later than C. quamash and one record-breaking flowering spike reputedly had 205 buds, although only three or four open at one time. The grey-blue starry flowers are symmetrical and there are white forms and double forms.

This species is named after Maximilian Leichtlin (1831–1910), the founder of Baden Baden’s botanic garden. It’s found in damp mountain meadows in western America, hence it prefers an open situation. It is much more statuesque with foliage that’s really good in damp soil, although the leaves will flop in drier conditions.

The Caerulea Group, more correctly called C. leichtlinii subsp. suksdorfii Caerulea Group, bears rich, lavender-blue flowers in May and June and reaches 3ft. It was collected in 1880 by W. N. Suksdorf from damp meadows in the Falcon valley in Washington State and we know that Canon Henry Ellacombe (1821–1916) grew it in his Gloucestershire garden at Bitton near Bristol. Avon Bulbs now sells a refined form named Maybelle, with purple-blue flowers middled in green.

Stella rates Blue Heaven and Blue Candle, both crosses between C. cusickii and the Caerulea Group. Blue Heaven has paler, sky-blue starry flowers, each with a pale-green centre. The eye-catching hybrid Blue Candle opens slightly later and has smaller, denim-blue stars that emerge from grey-blue, lupin-like buds. Both relish clay soil, reaching 2½ft high.

The great thing about these stalwarts is that they clump up well and return year after year, needing little attention and flowering in May when little else does.

No wonder Stella is planning a trip next spring to follow the Lewis-Clark trail to see wild camassias in bloom.

Stella Exley, Hare Spring Cottage Plants (perennials and camassias), Alne, North Yorkshire — www.harespringcottageplants.co.uk

The history and origins of camassias

Camassia bulbs were an important food plant for many North American natives and the flower-rich meadows were fought over by different tribes who made cake from camassia flour and stored the cooked bulbs over winter. The plant was officially discovered in 1806 by Capt Meriwether Lewis and William Clark, plant hunters and explorers sent by President Thomas Jefferson to find a navigable route to the Pacific, shortly after the Louisiana Purchase of 1803.

Lewis wrote in his journal on June 12, 1806: ‘The quamash is now in blume and from the colour of its bloom at a short distance it resembles lakes of fine clear water, so complete in the deseption that on first sight I could have swoarn it was water.’

Many thought that Lewis and Clark had perished along the way — and they might well have done had it not been for their Indian guide and translator, Sacagawea, a Lemhi-Shoshone woman. When the expedition leaders and their men were close to starving, she foraged for wild food and led them to the bulb-rich meadows of Weippe Prairie in Clearwater County in Idaho. Here, she cooked quamash bulbs that made Clark and some of the men feel very ill, but the fermented roots apparently made good beer.

Sacagawea is honoured by two statues and a white-flowered variegated form of C. leichtlinii Sacajawea has been named by Dutch bulb expert Aad Kroon. This has good winter foliage and, as do many of the white-flowered forms, looks best in dappled light.