Trilliums go dormant in the summer so plant them with other plants that produce a show then to hide the foliage of the trilliums. Trilliums love rich soil that never dries out. Look to trilliums in the wild for ideas as to how to plant them in your own garden. Trilliums love the dappled sunlight that filters through leafless trees in early spring. Once the leaves are fully out in the trees, the trilliums are dormant. So try planting your trilliums around deciduous trees.