Trillium sessile

Trillium sessile is part of a group of small wild plants native to North America and Asia, quite rare in cultivation, highly sought after by collectors of rare and precious plants. The American sessile species is as unusual as it is beautiful, and relatively easy to grow in moist soil. Nestled in the heart of a cluster of leaves, a narrow and erect flower emerges in spring, ranging from purple-brown to dark red, emitting a musky scent that can surprise or displease. Before the flowers appear, the plant captivates with its delicately marbled young foliage in purple or silver. It will be stunning planted en masse in a wooded garden or in an exotic-inspired bed, always in filtered light.

Trillium sessile, formerly classified in the Lily family, now belongs to the Melanthiaceae family. It is a distant North American relative of the fragrant Solomon's Seal that populates our European forests. It is native to the northeast of the United States, where it blooms in spring in floodplain forests, in the understorey, and along watercourses, on sometimes calcareous, loamy, or peaty soil.

Trilliums are very special plants that do not develop true stems or true leaves. The vegetation that emerges in spring is actually just a flowering, composed of an upright petiole, an extension of the rhizome, bearing a coloured flower that rises above bracts resembling leaves. The true leaves, tiny and scale-like, are found on the flower's petiole. 

A herbaceous and perennial plant, Trillium sessile develops in spring from a fleshy and thick underground rhizome 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 and slender leafy stems, standing at 15-20 cm (6-8in) above the ground. Thanks to its rhizomes, this Trillium will slowly form small colonies occupying at least 30 cm (12in) of the ground. Each stem bears only 3 beautiful leaves inserted at the same level on the stem and arranged horizontally. The leaves are round to lanceolate in shape, beautifully undulated, of a vibrant green colour, with prominent parallel veins. They measure about 12 cm (5in) long and 10 cm (4in) wide. They are often marbled with brown, purple, or small silver areas when young. The flowering takes place in April-May, more or less early depending on the climate, in the centre of the trio of leaves. The upright flower, 5 cm (2in) tall and narrow, is composed of 3 petals ranging from brown to dark red. This flowering with its spicy and musky scent attracts flies and beetles. This species is very difficult to propagate by sowing. Trilliums seeds are dispersed by ants. Plants grown from seeds can take several years to flower. 

A bit slow to establish, this Trillium sessile is long-lived, and requires little care where it is happy. It should be planted in groups of 3 specimens in woodlands or dappled sunlight (introduce several plants in a small area), in soil rich in humus or leaf compost that remains moist for as long as possible. It pairs well with other small perennials that enjoy the same environments, such as Mertensia virginica, with its springtime blue flowers. Plant flowering plants or interesting foliage that will fill the ground in summer, while the trillium rests underground: consider Ophiopogons, Saxifraga, small ferns, Asarum, hostas, etc. It can be grown in pots, with careful watering. In the ground or in pots, it always makes a successful pairing with Begonia grandis subsp. evansiana, which takes over its flowering.

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 colored petals, six stamens, and 3 fused carpels.