There are many Sedum in the world but few garden-worthy species hail from North America. Sedum spathulifolium is one exception. This article will introduce you to this delightful western North American native.
(Editor's Note: This article was originally published on October 17, 2009. Your 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.)
That vast majority of ornamental, hardy Sedum (including the recently split Hylotelephium and Rhodiola) are native to Eurasia. One notable exception is Sedum spathulifolium, commonly called Pacific, broadleaf or yellow stonecrop. This species is native to western North America from British Columbia south to California. In the wild, they grow on rocky slopes, from sea-level to 7500 feet, oftentimes in considerable shade. Here, they grow among Douglas fir or yellow pine forests. For a sedum, they can tolerate considerable moisture, as long as it doesn't gather around their crowns, yet they are also drought-tolerant.
This species is quite low, usually under 15 cm. Their leaves are somewhat rounded, thick and fleshy with a unusual white powdery coating which lends them a white to grey-green appearance. In early summer, they produce flat-topped clusters of yellow flowers. In winter, the plants often turn reddish to purplish, making them invaluable in the winter garden. In fact, this plants foliage seems to change colour constantly all year round. They are particularly well suited for mixing among Sempervivums and other low stonecrops in the rockery, front of the perennial border or alpine troughs.
Floral details of S. spathulifolium
In the garden, provide them with sun to part-shade and well-drained soil. Their pH tolerance ranges from 5 to 8. They are hardy from zones 4 through 10. They may be grown from seed (except named cultivars) but root so easy from cuttings, that sowing from seed seems pointless.
Above are some of the seasonal variations in 'Cape Blanco'
There are several named selections. The most popular is probably 'Cape Blanco', often mis-named ‘Capa Blanca'. This selection has notable powdery foliage and is best described as pewter-coloured. It is more compact than the wild species. It has been given an Award of Garden Merit by the RHS. 'Carnea' and ‘William Pascoe' are two similar selections that lack the powdery coating. They more clearly show red (‘Carnea') or purple-red (‘William Pascoe') tinted foliage. ‘Aureum' has the perhaps the best foliage, being green at the base, yellowish in the middle and reddish-pink tinted at the tips. 'Red Raver' is a powderless selection whose leaves are shiny, the older ones being red while the newer are bright green.
A more tender, close relative is the pink-flowered S. laxum, commonly called the roseflower or Siskiyou stonecrop. This species is found in northern California and neighboring Oregon. It also has somewhat powdery foliage and hence a greyish appearance. In the wild, natural hybrids exist between this species and S. spathulifolium. They have been named 'Moonglow' and 'Silver Moon'. Both are light grey-green with a slight red tint and have yellow flowers. Alas, they are not as hardy as the pure S. spathulifolium. A purposeful hybrid between ‘Silver Moon' and S. spathulifolium ‘Carnea' resulted in 'Harvest Moon', which looks like a larger, more vigorous version of ‘Cape Blanco'.
Above are two hybrids: 'Silver Moon' and 'Harvest Moon'
Whether you prefer flowers or foliage, this little North American stonecrop can fit the bill for year-round interest. If you've never tried growing one, then perhaps you should!
I would like to thank the following people for the use of their pictures: Calif_Sue ('Cape Blanco'), colliwobbles ('Harvest Moon'), growin (thumbnail), Happenstance ('Cape Blanco'), palmbob ('Cape Blanco'), PotEmUp ('Silver Moon') and scorpioangel (flower closeup).
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.