Trilliums grow from a rhizome, emerging in March or April, flowering, setting seed and dying down from July to October. Most trilliums are fully hardy.
Trilliums are perfect planted between shrubs that provide both shade and shelter from the wind. Alternately, a shady border against a wall or fence is a good location. Trilliums prefer a neutral to acid soil, but they will grow successfully in a good fertile soil that is rich in organic matter and does not dry out. In dry and sandy soils, line the bed with polythene to retain moisture but put in several puncture holes to allow excess moisture to drain away.
Although trilliums are moisture lovers, they will not tolerate waterlogging. They will not thrive on heavy, wet clay soils. Planting in raised beds are a solution. Another is to dig out the clay to a spades depth and fill with a mixture of loam, garden compost, well rotted manure and composted bark bulked up with sharp sand. Mound the material so it is at least 10cm (4in) above the surrounding soil level. This allows plants to root deeply but avoids them sitting in waterlogged conditions over winter.
Trilliums should be planted about 7-10cm (2½-4in) deep. The best time for planting is late summer as it gives the rhizomes time to establish good root systems before the following growing season.
Keep well watered during dry weather in spring and early summer. Apply an annual mulch of well decayed organic matter in early spring. A light application of a balanced fertiliser in late winter is also beneficial.
Trilliums do not really thrive in containers as they prefer a moist, rich garden soil. But you can try them in pots of sandy loam, such as John Innes No. 3 with added gritty sand.