Trillium nivale (snow trillium)
Trillium nivale Riddell
snow trillium, dwarf white trillium
NatureServe Status: G4 - Apparently Secure
Damp woodland, on slopes and rocky ledges or near streams often on limestone.
About this species
The snow trillium is one of the earliest spring blooming alpines, the common name referring to the fact that snow can often be found on the ground when the flowers appear. It is one of the smallest Trillium species, and it is also notable for its longevity. Its seeds are dispersed by ants.
As the generic name suggests, trilliums have parts arranged in threes: three leaves, three sepals (the part of the flower that protects the flower in bud) and three petals.
Trillium nivale was illustrated by Sir Joseph Hooker’s daughter Harriet Thistelton-Dyer in Curtis’s Botanical Magazine in 1879.
Geography and distribution
This species is found in scattered localities in the eastern and midwest United States, mainly in an area stretching from West Virginia and Pennsylvania, through Ohio, Indiana, Illinois and Iowa, to southern Minnesota, Wisconsin, and Nebraska.
Trillium nivale grows only 5–15 cm tall. The elliptic to ovate (the shape of an ellipse or an oval) leaves continue to expand as the flower fades, eventually reaching around 5 cm long.
It usually displays wide, showy flowers with white petals, which are sometimes faintly veined with pale pinkish-purple. The pedicel (flower stalk) is 1–3 cm long. The flowers are held erect at first but become nodding with age and are large for the size of the plant, reaching over 4 cm wide.
The fruit is a berry with several seeds that are dispersed by ants.
Threats and conservation
The conservation status of snow trillium is classified as ‘Apparently Secure’ (G4) according to the NatureServe Conservation Status Ranks.
Several threats are listed under this status:
- may be threatened by habitat destruction such as quarrying and logging
- threatened by exotic species invasion in Maryland
- may be threatened by grazing in Nebraska
- may be threatened by alterations to hydrology that increase flooding in Michigan.
Trillium nivale is cultivated as an ornamental.
Trilliums are often grown in the dappled shade and moist soil of a woodland garden. Because of its small size, Trillium nivale is well-suited to cultivation in a rock garden if grown in partial shade and neutral to alkaline, gritty, humus-rich soil. It also makes a fine plant for pot cultivation, housing it in a well-ventilated cold frame will protect its early blooms from wind and rain. Shoots appear above ground early in the year and are susceptible to slug damage.
The best way to propagate T. nivale is from fresh seed. This normally needs two cold periods before germination, so seedlings may not appear for nearly two years. The seed may germinate straight away if sown just before it is ripe, but seed that has been stored may germinate erratically or not at all. Seedlings can be left in their pot for a year or two before potting up in late summer.
They will take three or four years to flower. This is a very long-lived species, rarely available, but often seen in specialist collections where plants over 20 years old are known.
This species at Kew
Snow trilliums can be seen in the Davies Alpine House when in flower.
NatureServe – Trillium nivale. Available online (accessed 15 April 2011).
Smith, B.H., Forman, P.D. & Boyd, A.E. (1989). Spatial patterns of seed dispersal and predation of two myrmecochorous forest herbs. Ecology 70:1649-1656.
Wilford, R. (2010). Alpines from Mountains to Gardens. Royal Botanic Gardens, Kew.
Kew Science Editor: Malin Rivers and Richard Wilford
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