Trilliums

Trilliums are beginning to bloom in some of our woodlands and gardens in May.   This lovely native was once common on the edges of woodlands but is no longer found in many places.   Trilliums are a favorite deer food and they have a complicated life cycle which leaves them vulnerable in many places.  They are sold by nurseries however and a gardener can add them to the partly shaded garden.

Trilliums come in several species, the Large White Trillium, Trillium grandiflorum, sometimes called Wake Robin, which turns pink as the flower ages,  Trillium erectum, a reddish marron flowered  (sometimes yellowish) with a bad odor to justify the name  Stinking Benjamin, Trillium sessile, or Toadshade, with mottled leaves and a reddish flower that never opens fully, Trillium undulatum, Painted Trillium which has small white flowers with purple centers,  and  Trillium  cernuum,  Nodding Trillium, whose tiny white flowers dangle beneath the leaves.  All of these are Eastern North American species which can be found from Florida to Canada.  There are a few other species in North America and in Asia.

Trilliums are named that because everything about them comes in three’s, 3 leaves, 3 petals, 3 sepals, 6 stamens (3 pairs), 3 stigmas.  Occasionally a trillium will have double flowers.   The trillium puts up a single stalk with 3 dark green, long oval shaped leaves with prominent veins.   In most species the single flower appears in the center of the leaves.  The flowers are glossy and also have prominent veins.  The Large White Trillium has flowers 3-5 inches across, other species have smaller flowers.    Flowers are pollinated by flies and small native bees.  Trilliums are not self-fertile so 2 or more trilliums must be close together to get seeds.  The flowers, if pollinated, turn into 3 chambered seed pods.  Each trillium only produces a few seeds.

Trilliums also reproduce by slowly spreading from rhizomatous roots.  They will, after many years left undisturbed, produce large colonies of plants.  However if a plant loses its leaves early, by deer grazing or people plucking them with the flower, the plant may die.  Since the plant is endangered or scarce in many places it’s not ethical to pick the flowers or disturb the plants.  Trilliums are not easy to transplant, with many plants dying in the process so don’t dig them from the wild either.

Trillium seed has an oily coating called the elaiosome, which is attractive to ants and yellow jackets.  They carry the seeds to underground nests and eat off the coating.  The hard seeds are then in a protected place for the 2 years required for them to germinate.   Deer also move trillium seeds when they eat the plants and seed pods.  The elaiosome is removed by the deer’s digestive system and the seed passes out in deer poop, which will hopefully land in deep forest litter to shelter it for two years.

After two years the trillium seed germinates and produces a leaf stalk.  They will not bloom for several years about 5 years in gardens and 7-10 years in the wild.  Once they begin blooming they will bloom for many years, (its believed plants can live for at least 20 years), one bloom per year, if they are undisturbed.  This slow rate of reproduction is what causes many colonies of trilliums subject to deer grazing and human mishandling to disappear.

Trilliums in the garden

Despite what some nurseries claim, most trilliums offered for sale are not grown by the nursery, rather they are collected from wild colonies, maybe on the nurseries property or property where they purchase the rights to harvest them.  In a few cases, double flowered or other unusual trilliums may be grown in nurseries, but due to the slow reproduction of the plants these varieties will be scarce and expensive.  If the species is not listed as endangered in that state trilliums are legal to collect and sell.  And if you purchase them legally you do not have to worry about planting them in your garden.

Before you purchase trilliums make sure you have the right conditions for them.  Trilliums like deciduous wooded areas.  That means they like areas where they will get full sun early in the spring before the trees leaf out and then shaded conditions in the heat of summer.  They like moist but well drained soil with a high amount of organic matter and good fertility.  The soil pH should be neutral to slightly acidic for most species. Preferably the leaves the trees shed each fall will be left in the bed to make a “duff” or organic mulch.  The area they are planted in should not be disturbed often, certainly not mowed.  Trillium leaves need to remain on the plant until they die of their own accord, in late summer.

A woodland type garden with plants that have similar needs such as May apples, bloodroot, trout lilies, anemones, lily of the valley, Jack in the Pulpit, toad lilies,  and so on would be the best fit for them.  They would not do well in containers, rock gardens, and heavily cultivated garden beds. 

Trillium should be sold and planted in the fall.  You will generally receive bare root pieces to plant.  Plant them as soon as you receive them in moist soil with the rhizomes about an inch deep in the soil and about 6 inches apart.  Cover with a light mulch of leaves.  If fall is dry water the trillium occasionally.   Make sure to mark the location well.   You don’t want to plant on top of them or cut through their roots.

In mid to late spring foliage should emerge.  Sometimes trillium will not emerge the first season after you plant them so don’t be too quick to think they are dead.  Keep the spot marked and undisturbed until the second spring.  Some trillium will bloom the spring after you plant them but some will just make foliage for a year or two.  Be patient and they will flower eventually.

You may have to protect the trillium from deer.   Deer love the taste of trillium and will bypass other plants to eat them.  One or two years of the foliage being eaten will kill the plants.  They often eat them just as they start to bloom.  A fenced woodland garden may be needed.

As mentioned above, do not remove the trillium's foliage until it dies down of its own accord.   They have few leaves and each one is needed to produce food for the plant as long as possible.  If you want the trilliums to spread by the roots don’t cultivate the ground close by the plants.  The only other care they may need is to water them if it gets very dry.  A light application of slow release  garden fertilizer in early spring  may help blooming. 

Native Americans had herbal uses for the plant but it’s not recommended that trillium be used for herbal concoctions.  They are mildly toxic, but the main reason to just leave them alone is that the plants just don’t compete well with humans and deer and are becoming rare in many places.  There are no herbal uses for them that other more common plants can’t be used for.  Please just enjoy them where they are.  Beauty is as good a purpose for trillium being there as any other reason.