Helichrysum thianschanicum (occasionally also spelled as tianschanicum) is native to the Tian Shan mountains, on the border between Kazakhstan and the Xinjiang Autonomous Region of western China. It's an evergreen woody perennial that forms a tight mound of eye-catching silver foliage around 1½-2' high and reaching 2-2½' wide. Clusters of yellow flowers bloom in mid-summer.
Natural habitat and range
Helichrysum thianschanicum (occasionally also spelled as tianschanicum) is native to the Tian Shan mountains, on the border between Kazakhstan and the Xinjiang Autonomous Region of western China where it's found growing on dunes, gravelly areas, and slopes below 9,800 feet. This area is very hot, dry and sunny in summer and extremely cold in winter. The plant's tolerance of these harsh weather extremes in its natural habitat indicate it should do well in California.
Growth habit and flowers
Curry plant forms a tight mound of eye-catching silver foliage around 1½-2' high and reaching 2-2½' wide. The slender leaves are about 1" long and reminiscient of rosemary, lavender or westringia. The young stems are also silver “thin dense whitish-grayish tomentose pubescence,” to quote Eduard August von Regel, the botanist who named the plant.
When crushed, the leaves emit a very, very faint aroma of curry powder. This aroma's nowhere near as pungent, though, as the leaves of its close relative, Helichrysum italicum which is also called curry plant. Very confusing! Neither of these plants, by the way, provide the curry leaf that's sometimes used in Indian cooking. This comes from the curry tree (Murraya koenigii), a small tree that's native to India and Sri Lanka. In case you were wondering, the spice mix, curry powder, has nothing to do with either of the curry plants or the curry tree. It's a powdered blend of several spices and usually includes coriander, cumin, turmeric, cardamom plus others.
Curry plant produces clusters of small sunshine yellow flowers in mid-summer. They aren't particularly showy, but contrast strkingly with the silver foliage.
Plant curry plant in a location where it'll receive at least half a day of sun.
Curry plant's tolerant of most soils, including clay. However, it doesn't want to be sitting in soil that's constantly waterlogged.
Once established (a year), curry plant will survive in coastal areas with no supplemental water. In hotter inland areas, it will probably also survive with no summer water. However, it will look better with occasional deep watering.
Pests and Diseases
Occasionally, the fresh young spring growth will attract a few aphids (small, round-bodied insects with piercing mouthparts that suck sap from plants). However, the infestation isn't usually worth worrying about. If necessary, the affected stems can be pruned off.
The silver foliage of curry plant combines well with most colors including dark green, burgundy, yellow, chartreuse and lime green. It works well in mixed borders or in containers. It's particularly striking mass-planted on slopes with large ornamental grasses.
Care for this perennial is very similar to how you'd take care of lavender. After the flower heads have died, use a pair of hedging shears or large scissors to trim off the flower stems plus about 1-3" of the leafy stems.