Yellow trout lily (Erythronium americanum) is a native North American woodland plant with nodding yellow flowers that appear between March and May. This ephemeral spring bloomer may take a few seasons to begin producing flowers, but once established, it blooms beautifully and forms colonies if given the proper growing conditions. The plants' mottled foliage resembles the markings of a brook trout (hence the common name) and make trout lily an attractive seasonal groundcover. The foliage fades after the plant blooms, but it's a long-lasting plant that spreads into large colonies over time. It is also a good addition to woodland and pollinator gardens, as it attracts mining bees (Andrena erythronii) that pollinate other spring-flowering bulbs, ornamentals, trees, and shrubs.
Yellow trout lily is normally planted from corms in fall, or by seeds sown in late spring or early summer. It is a relatively slow-growing plant; root divisions may not flower until their second year, and seedlings can take as much as five or six years before they flower.
|Common Name||Erythronium americanum|
|Botanial Name||Yellow trout lily, yellow dogtooth violet, yellow adder's tongue|
|Plant Type||Herbaceous perennial|
|Mature Size||3-6 in. tall, wide|
|Sun Exposure||Partial, full shade|
|Soil Type||Moist, humusy, well-drained|
|Soil pH||Acidic (below 6.8)|
|Hardiness Zones||3–8 (USDA)|
|Native Area||Eastern North America|
Yellow Trout Lily Care
The elongated corms of the yellow trout lily, like other garden lilies, lack a hard outer skin, which makes them prone to drying out. Therefore, it’s important to plant the corms as soon as you buy them or divide existing plants. The curved, elongated shape of the corms is the source of the other common name for this plant—dogtooth violet.
Trout lily is best planted in a location where it can spread and naturalize. Plant them about 5 inches deep and 4 to 5 inches apart for a colony effect. When weeding around it, make sure not to damage the offset corms that develop, as these are the source of new plants. Many ants in or around the plants are a welcome sign, because trout lily has a symbiotic relationship with ants—they spread the seeds and help the plant naturalize. After the foliage dies back in the summer, leave it in place as a natural mulch all through the winter.
The best place to grow trout lily is an east-facing location with morning sun. In its native habitat, trout lily grows underneath deciduous trees, such as oaks and maples. In the early spring, before the trees have leafed out, this setting provides ample sunlight, which the plants need to thrive and bloom. Later, during the summer, an ideal site has dappled to full shade to protect the plant from the hot midday and afternoon sun.
Trout lily can grow in any light, moist soil that is rich in humus, similar to the soil in its native habitat. Dense garden soils should be heavily amended with compost to create an ideal environment. Soil pH should be on the acidic side, below 6.8.
The plant needs moisture during its spring growing period, about 1 inch of water per week from rain or irrigation. In the summer, after trout lily has gone into dormancy, it requires drier conditions, and no watering is needed.
Temperature and Humidity
Yellow trout lily is hardy in zones 3 to 8, easily surviving temperatures as low as minus 30 degrees Fahrenheit. Native to forests and damp meadows, this plant handles humid conditions but will not tolerate extreme dry heat.
This plant does not need extra fertilizer if it is planted in rich, humusy soil. Instead, top-dress with more organic matter each spring before the new growth starts.
Types of Trout Lily
Yellow trout lily does not have any widely available named cultivars, but the Erythonium genus includes several additional species that are collectively known as trout lilies. Among those that are often cultivated for garden use:
- Erythonium almidum (white trout lily or white dogtooth violet) has white flowers with lavender-colored blotches. It is also native to the eastern U.S. and is hardy in zones 4 to 9.
- Erythonium dens-canis (dogtooth violet) is a native of southern Europe. It has rosy violet flowers and blooms in late spring. It is hardy in zones 3 to 8. Several named cultivars are available, including 'Lilac Wonder', 'Pink Perfection', and 'Purple King'.
- Erythonium grandiflora (yellow glacier lily) is a considerably taller plant, growing to nearly 2 feet. Native to the Northwest, it blooms in late spring and is hardy in zones 4 to 8. It does not have the mottled leaves seen on the other species.
- Erythronium revolutum (pink fawn lily or mahogany fawn lily) has pink flowers on 12- to 14-inch plants. Native to the Pacific coast from Northern California to British Columbia, it is hardy in zones 5 to 8. 'Pagota' is a hybrid form with bright yellow flowers.
Propagating Trout Lily
Trout lily is very finicky to grow from seed, so it’s best propagated by division of the offset corms. After several years, when the plants have grown into leafy clumps, it’s time to divide them. Here's how:
- In spring, mark the location of the plants, so you know where to dig the corms in the late summer.
- In late summer, dig up the plants and carefully divide the offset corms from the parent corms.
- Replant the corms about 4 inches deep, and mulch them well.
How to Grow Yellow Trout Lily From Seed
It can take as much as five or six years to produce mature flowering plants when propagating yellow trout lily from seeds, so it's rarely done except by developers seeking hybrids or by very serious amateurs looking to experiment. However, if you have sufficient space to develop a colony of yellow trout lilies, then you can direct sow seeds just as the seed capsules split in summer. Sow seeds immediately, as the seeds lose viability quickly. In the initial season, no seedlings will be evident, but the following spring you will likely see the grass-like seedlings appear. But it will be at least two years before the plants are recognizable, and an additional two or three years until the plants blossom.
Potting and Repotting Yellow Trout Lily
This plant is best suited to colonizing in semi-shady woodland and meadow gardens. It is a spring ephemeral that does not lend itself well to container culture.
How to Get Yellow Trout Lily to Bloom
This plant typically produces a single drooping flower per stalk, with a bloom period that lasts about two weeks. The exact window for blooming varies depending on region, but usually falls somewhere between March and May. Not every plant will produce flowers stalks on any given year.
A colony of yellow trout lilies will generally bloom reliably if planted in humus-rich soil in a partly shady location, but the plants do not respond well to dry soils or too much sun. If flowering is sporadic but the plant colony produces abundant foliage, it may be time to divide the plants to produce better flowering.
Common Problems With Yellow Trout Lily
A common complaint from gardeners unfamiliar with this plant is that it vanishes rather quickly after the flowering period is over. This is a common feature of all spring ephemerals, which leaves the gardener with the challenge of filling the empty area of the garden. This species is often planted along with ferns, summer snowflake, primroses, and other plants that enjoy shady conditions and can fill in after tout lilies have faded. Make sure not to remove foliage prematurely after flowering, as it absorbs nutrients and sunlight to feed the corm. Allow the foliage to die back naturally.
How should I use this plant in the landscape?
Yellow trout lily works best when naturalized in shady areas with moist soil. Shady areas of native plant gardens, shade gardens, woodland gardens, ponds and stream backs, and shady rock gardens are all appropriate places for yellow trout lily.
Can I transplant wild specimens into my garden?
Yellow trout lily is a plentiful wildflower in the forests and damp meadows of eastern North America, especially Canada and the Northeast U.S.. But it's not a good idea to remove any wildflower from its natural habitat, and may even be illegal in some areas. Nor does yellow trout lily transplant well. If you want to add trout lily to your landscape, make sure to obtain it from a commercial nursery that follows wildflower ethics in its propagation methods.
How long does yellow trout lily live?
When allowed to spread gradually in a well-suited location, a colony of yellow trout lily can survive for well more than a century. There are wild colonies thought to be more than 1,000 years old.
Is yellow trout lily edible?
Yes. The corms of yellow trout lily were often cooked and eaten as a vegetable by North American Indian cultures. The corms can also be eaten raw; the taste resembles that of cucumber.
Clausen, Ruth Rogers, and Christopher, Thomas. Essential Perennials. Timber Press, 2014
Erythronium Americanum, Lady Bird Johnson Wildflower Center.
Hinkley, Daniel. All About Trout Lilies, Horticulture Magazine, April 30, 2007
Erythronium Americanum, Missouri Botanical Garden.
Yellow Trout Lily (Erythronium Americanum), Virginia Native Plant Society.