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How to Grow Trillium, a Native Woodland Plant

Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.

Trillkum grandiflorum, native to Eastern North America

Trillkum grandiflorum, native to Eastern North America

I was touring a botanical garden one early spring day and was admiring their trillium collection. Then I saw it. The one that I had to have: Trillium recurvatum. Deep red flowers, mottled leaves. It would look perfect in my shade garden. It was a long multi-year hunt, but I finally found a nursery that sold them. Now they make me smile every spring.

What are Trillium?

Trillium (Trillium spp) is the name of a plant genus that has upwards of fifty different species found in temperate areas of Asia and North America. Here in the US, we are most familiar with the 36 species growing in our woodlands, most of them in the Southeastern woodlands. Trillium species can also be found in Southeastern Canada. In Asia, there are species spread from the Himalayas east through China, Korea, Japan and the Kuril Islands of Russia. Japan has the most species.

Trillium is hardy in growing zones 4 – 9. Depending on the species, they range in height from 1 to 2 feet. They are known as the Trinity flower because they have three leaves, three petals and three sepals. The leaves are not true leaves. They are bracts but unlike most bracts they can photosynthesize like leaves. The plants grow from rhizomes. Each rhizome grows one three petalled flower that can be red, pink, white, purple, yellow or green depending on the species. When the flowers die, green fleshy pods referred to as fruit appear. In some species, they look like berries.

Trillium have an interesting way to disperse their seeds. Each seed has an elaiosome. An elaiosome is a fleshy structure that contains an oily substance that attracts ants. The ants harvest the seeds to bring back to their nests to feed the elaiosomes to their larvae. This is so specialized that only certain ant species collect the seeds of certain trillium species. After the elaiosomes are eaten, the ants dispose of the seeds outside of their nests thereby spreading the seeds far from the parent plants.

Trillium recurvatum, native to the Midwest.

Trillium recurvatum, native to the Midwest.

How to Buy Trillium

Although trillium grow wild in our woodlands, you should never try to transplant them from their woodland homes to your own garden. Many trillium are endangered and in some states it is illegal to harvest them from the wild.

Trillium growing in the wild is nearly impossible to successfully transplant. They grow in a dense mat and digging up one will disturb the others. When you try to plant the rhizome in your home garden, the conditions are so different that the plant will most likely die. Even just picking the flowers or foliage can kill the rhizomes.

Always purchase trillium plants or rhizomes from a reputable nursery. If you are not sure, ask where they get their plants or rhizomes from. Reputable nurseries either grow their own in onsite woodland gardens or are licensed to harvest wild rhizomes from public or private lands. If they are harvesting rhizomes without a license or claim that no license is needed, do not buy from them. They are contributing to the decline and eventual disappearance of these woodland plants.

Try to purchase trillium that are native to your area of the country. Trillium species that are native to the Western parts of the US have different soil and water requirements from species that are native to the Eastern parts of the US. You will be most successful growing the same species that are also found in your local woodland areas.

Trillium luteum, native to the Great Smoky Mountains

Trillium luteum, native to the Great Smoky Mountains

How to Grow Trillium

Before you order and plant your rhizomes, you will need to prepare your garden. Pick a shady to semi-shady spot in your yard with slightly acidic soil and lots of leaf mold. The further south you are, the more shade your plants will need. Acidic soil and leaf mold mimics the conditions in their woodland homes. If your soil is clay, you can amend it with lots of leaf mold. Leaf mold is simply leaves that have fallen in your yard in the autumn. You can use your lawnmower or a wood chipper to shred them so that they break down faster instead of becoming a wet, soggy mat.

The best time to plant your rhizomes is in the late summer or early fall when they are dormant, so you will have a whole year to add the leaf mold you made from the leaves that fell the previous autumn. Don’t stop making leaf mold. You will be adding it to your trillium garden every year just as nature adds a fresh layer of leaves every autumn.

When you receive your rhizomes, they will be dormant. Plant them 2 to 3 inches deep and 6 to 12 inches apart. They do not need to be watered because they are dormant. Too much water will rot the rhizomes. They are native plants and well adapted to growing in your area with no help from humans unlike the delicate flowers and vegetables in our gardens that have been hybridized over hundreds of years and now require constant care to survive.

Trillium do not need to be fertilized. Just give them a side dressing of leaf mold in the spring when they appear, and then again in the fall. They are not bothered by disease. Deer will lightly browse them if you have deer in your area. Their worst “predators” are slugs and snails. My favorite methods for dealing with slugs and snails are to surround my plants with a ring of crushed eggshells that will kill them and to set beer traps to attract them away from my plants. They fall in to the traps and drown.

The plants will come up in the early spring, bloom and then the tops of the plants will turn yellow and die by mid-summer and the rhizomes will go dormant until the following spring. There is no need to remove the dead foliage unless you like your gardens to look neat.

How to Divide Trillium

Trillium spread by underground runners so they can become a dense mat of plants in your garden that need to be divided. Trillium do not like to be disturbed so this is a delicate operation. In the spring, mark where your plants are that you want to divide. In the late summer when the rhizomes are dormant, carefully dig them up. You can divide them by gently pulling them apart with your hands. Then replant the rhizomes 2 to 3 inches deep and 6 to 12 inches apart.

How to Grow Trillium From Seed

Growing trillium from seed requires great patience. You will need fresh seed harvested from your plants. If you see trillium seeds offered for sale, don’t waste your money. Those seeds have been dried and will not germinate. You need freshly harvested seed. Surface sow the seeds in your garden just as they would be sown in nature and then wait. And wait. And wait. It will take about 2 years for the seeds to germinate.

Once the seeds have germinated, it will be another 5 to 7 years before they flower. This is because they need to grow their rhizome large enough so that they will have the energy to make flowers.

© 2020 Caren White