Trillium pusillum - Dwarf Trillium

Trillium pusillum is one of the smallest species of North American trilliums, but also one of those that bloom the earliest in spring. This small perennial offers, above a trio of lush green leaves, a widely open flower with 3 white, wavy petals that quickly turn pink. It thrives in moist, humus-bearing soils and woodland settings where it slowly spreads through its rootstock. Quite rare in cultivation and little known to European gardeners, trilliums should to be tried in shaded, moist areas. They eventually form an unusual spring carpet in a wooded garden or a shaded rockery.

Trillium pusillum, long classified in the family Liliaceae, now belongs to the Melanthiaceae family. It is a distant North American cousin of the fragrant Solomon's seal that populates our European woodlands. It is native to the southeastern and central-southern United States (from Oklahoma to Maryland), where it blooms in early spring in various types of habitats. It can be found in savanna-like formations as well as in swamps and turf moors, in forests, woods, and fields, always on acidic soil.

Trilliums are very unique plants that do not develop true stems or true leaves. The vegetation that emerges in spring is actually a flowering, consisting of an upright petiole, an extension of the rootstock, bearing a colourful flower that sits above bracts that resemble leaves. The true leaves, tiny and scale-like, are found on the petiole of the flowers.

A herbaceous and perennial plant, Trillium pusillum develops very early in spring from a slender, branching, horizontal underground rootstock that does not like to be disturbed. It goes dormant as soon as the soil dries out, during the summer, or in autumn due to the cold. The plant produces short, slender leafy stems, rarely exceeding 15 cm in height.  Thanks to its rootstocks, this Trillium will slowly form small colonies occupying at least 20 cm of ground. Each stem bears only 3 leaves growing at the same level on the stem and arranged in a triangle, horizontally. The ovate leaves are a lovely dark green, sometimes tinged with red when young, and marked by prominent parallel veins. They measure about 10 cm long and 5 cm wide.  Flowering occurs in March-April, earlier or later depending on the climate, above the trio of leaves. The flower, borne on a petiole 6 cm wide, consists of 3 slightly wavy petals that change from white to pink, topped by 3 narrow green sepals arranged in a staggered formation. This flowering attracts the western honeybee (Apis mellifera), which pollinates it. This species is difficult to propagate by sowing. In trilliums, the seeds are dispersed by ants. Plants grown from seeds may take several years before they bloom.

A bit slow to establish, Trillium pusillum is nevertheless faithful, long-lived, and requires little care where it thrives. It should be planted in groups of 3 in woodland or dappled sunlight (introducing several young plants in a small area), in soil rich in humus or leaf mould that remains moist for as long as possible. It will pair well with other small perennials that enjoy the same environments, such as Mertensia virginica, with its bright blue spring blooms. Plants with staggered flowering or interesting foliage will fill the ground in summer, while the trillium rests underground: consider, for example, ophiopogons, saxifrages, small ferns, asarums, hostas, pulmonarias... Pot cultivation is possible, with careful watering. Whether in the ground or in pots, a grouping with Begonia grandis subsp. evansiana, which will take over its flowering, is always successful.

The Latin name Trillium derives from the fact that the different parts of these plants are ternary: from the unique cluster of three leaves on each stem to the construction of the flower, composed of 3 green sepals, 3 coloured petals, six stamens, and 3 fused carpels.