Trout lily is a native American woodland plant with nodding yellow flowers between March and May. It’s an ephemeral bloomer—trout lily produces only one flower per plant, few of the plants bloom at all, and not every spring—but the mottled foliage, which resembles the markings of a brook trout and gave the plant its name, are an attractive seasonal groundcover.
In mid-summer, trout lily goes into dormancy and the foliage dies back. Trout lily makes up for its sporadic bloom by being long-lasting and spreading into large colonies over time. Trout lily is also a good addition to pollinator gardens. It attracts mining bees (Andrena erythronii) that pollinate other spring-flowering bulbs, ornamentals, trees and shrubs, as well as berries.
The common name dogtooth violet is misleading because botanically, trout lily is a member of the lily family (Liliaceae). It's the toothlike shape of the underground rhizomes that gave the plant its name.
|Botanical Name||Erythronium americanum|
|Common Name||Trout lily, American Trout-lily, Eastern trout lily, Fawn lily, Yellow dogtooth violet, Adder’s tongue|
|Mature Size||Three to six inches height, three to six inches spread|
|Sun Exposure||Part shade to full shade|
|Soil Type||Silt, loam|
|Soil pH||Acidic below 6.8|
|Hardiness Zones||3 to 8|
|Native Area||Eastern Canada and Eastern and North Central United States|
How to Grow Trout Lily
As with all native wildflowers, trout lily should not be removed from its natural habitat. 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.
The tubers of the trout lily, like other garden lilies, do not have a hard outer skin, which makes them prone to drying out. Therefore it’s important to plant the tubers as soon as you buy them.
Trout lily is self-pollinating so you don’t need two plants. However trout lily is best planted in a location where it can naturalize. When weeding around it, make sure not to damage the corms that emerge from the plant. The will bury themselves in the soil and new lilies will grow from it.
Many ants in or around the plants is 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 leaved out, this setting provides ample sunlight, which the plants need to thrive and bloom.
Later, during the summer, there should be dappled 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.
The plant needs moisture during its spring growing period, about one 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
Trout lily is cold hardy and grows in temperate climate.
The plant does not need extra fertilizer. Instead, plant trout lily in rich soil and add more organic matter each spring before the new growth starts.
Propagating Trout Lily
Trout lily is very finicky to grow from seed so it’s best propagated by division.
After several years, when the plants have grown into leafy clumps, it’s time to divide them. Mark their location in the spring so you know where to dig the bulbs in the late summer. Replant the bulbs about three inches deep and mulch them well.
There are three other, similar species in the Erythronium genus:
- Minnesota dwarf trout lily (Erythronium propullans), also called Minnesota adder's tongue or Minnesota fawnlily, with pink flowers.
- Pink fawn lily (Erythronium revolutum), also called Mahogany fawnlily, with pink flowers.
- White fawn lily (Erythronium albidum) also called White dogtooth violet, has white flowers with lavender-colored blotches.
Trout lily does not have any known pests or diseases.