Trilliums are the quintessential American woodland wildflower, a symbol of spring that is just beginning to bloom now. With their resplendent flowers, unusual three-leaved whorls, and often high cost, it’s not surprising that gardeners might consider trilliums too finicky or difficult to grow. While some may be, there are species that thrive surprisingly well in gardens as well as woods.
There are close to 50 species of trilliums worldwide, the majority of which are native to eastern North America. The southeastern states in particular are rich in trilliums, but those that are most easily grown in our gardens range northward into Canada as well.
The name “trillium” is derived from the Latin “tri,” referring to the plant having all its parts in threes. The scapes, or flower stems, emerge in spring from an underground stem called a rhizome, which very slowly spreads and occasionally sends out offshoots. Over time, it may form a sizable clump of stems up to 18 inches in height.
Each scape has a whorl of three horizontally-set leaves, usually broadly oval in shape. The flower has three sepals, always green and pointed, and three showy petals ranging in color from white or pale yellow to red or purple. Trilliums are divided into two groups, depending on whether the flower has a stalk or not.
In the sessile group, the flower sits directly above the leaves, with the petals held upright; the leaves are mottled or patterned with silver, gray or maroon blotches. In the pedicellate group, the flower sits on a pedicel, or stalk, above the leaves, which are generally solid green. The flower petals in this group generally flare outward; and depending on the length of the stalk, the flower may face outward or hang below the leaves.
Sometimes, the whorled leaves emerge without a flower. It takes a trillium plant anywhere from 3 to 7 years or longer to produce a flower. Thus, it takes a long time for a nursery grower to produce a plant ready for sale, and this accounts for the high cost of trilliums.
But this is also the reason unscrupulous growers will harvest trilliums from the wild, pot them up, and call them “nursery-grown.” With loss of habitat and excessive harvesting, trilliums and other native wildflowers are becoming scarce in our woods. If you find inexpensive or bare-root trilliums available for sale, be wary of the source of that plant.
Make sure you are purchasing a true nursery-propagated trillium from a reputable grower. In our area, we are fortunate to have Spring Haven Natives and Perennials in Newburg as a quality source for trilliums and other native wildflowers.
So maybe you can afford only one trillium to start with. You will find, as I did, that one is not enough. You will want more, but patience is a virtue. As long as you site the plant properly and give it the minimal care that it needs, your trillium will be around for a long time, slowly expanding to form a showy carpet of blooms. You may find it spreading by seeds as well. Trilliums have delicate roots that are easily damaged, so it is best to leave the plants undisturbed once planted, although they can be divided with care in late summer.
Plant trilliums in the dappled shade of deciduous trees, in a moist but well-drained soil enriched with organic matter, such as compost or leaf mold. Use a mulch of shredded leaves replenished annually. You may need to water occasionally during dry spells, but over the summer the leaves will naturally die down. Once established, trilliums are both drought tolerant and cold hardy. And that’s about it for care.
An annual sprinkling of dolomitic limestone around the plant is also beneficial for those species that grow best in neutral to slightly alkaline soils. The showiest of all trilliums, the Great White Trillium (Trillium grandiflorum), with large white flowers slowly fading to pink, is one such species. Yellow Trillium (Trillium luteum), a sessile species with yellow citrus-scented flowers and leaves attractively splotched with silvery gray, is another trillium that I recommend for central Pennsylvania gardens.
Annette MaCoy is the consumer horticulture extension educator and master gardener coordinator for Penn State Cooperative Extension in Cumberland County. If you have garden questions, contact Annette at 240-6500 or by e-mail at firstname.lastname@example.org.