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Trillium, Genus, spp., Multiple species,

Genus
Multiple species

trilliums

Melanthiaceae

North America and temperate East Asia

Attracts Pollinators

SunPart Shade – Full Shade

WaterMedium

HardinessZones 4–9

Overview

Trillium is a genus of about 50 species of woodland perennials in the family Melanthiaceae, native to North America and to temperate East Asia. Each plant grows from a short rhizome and sends up a single stem 6–18 inches (15–45 cm) tall, topped by a whorl of three broad leaf-like bracts. A single flower sits above the leaves, built on a pattern of three: three green sepals and three petals in white, maroon, yellow, or pink, depending on the species. In some species the flower sits directly on the leaves, while in others it is raised on a short stalk. Plants are slow to develop, taking several years from seed to first flower, and the seeds carry an oily appendage that ants collect and disperse. The foliage lasts through spring and summer before dying back, and colonies enlarge gradually from the rhizome. Because recovery from damage is slow, plants that lose their leaves to picking or grazing may not return for years. Trillium grows in cool, humus-rich soil in the shade of deciduous woodland and needs winter cold to complete its cycle.

Native Range

Trillium is native to the deciduous and mixed woodlands of North America, with centres of diversity in the southeastern United States and the Pacific Northwest, and a smaller number of species in the Himalayas and East Asia. Plants grow on shaded, humus-rich forest floors.

Suggested Uses

Trillium is grown in woodland and shade gardens, native-plant collections, and naturalistic plantings under deciduous trees. It combines with ferns, Erythronium, and other spring woodland plants. Because wild collection has depleted some populations, nursery-propagated plants are used for garden planting.

How to Identify

Identify Trillium by its whorl of three broad bracts at the top of an unbranched stem, with a single three-petalled flower above. The leaves are often net-veined and sometimes mottled with bronze. Counting parts in threes, sepals, petals, and leaves, confirms the genus.

Appearance

Size & Dimensions

Height6" - 1'6"

Width/Spread6" - 1'

Colors

Flower Colors

red

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Flowers: April–May

Spring

Flowering occurs in spring, usually from April to May, as the woodland warms and before the canopy fully closes. Each plant carries one flower that lasts one to several weeks, ageing in some species from white to pink. Bees and flies pollinate the flowers, and ants later carry off the seeds.

Detailed Descriptions

Flower Description

White, maroon, yellow, or pink

Foliage Description

Green, sometimes mottled bronze

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0 (Acidic to neutral)

3579

Soil Types

loam peat

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Grow Trillium in cool, moist, humus-rich soil in partial to full shade beneath deciduous trees and shrubs. Work leaf mould into the soil and keep it moist through the growing season, allowing it to dry only slightly in summer. Plants are hardy across USDA zones 4 to 9 and need winter cold to flower. Establishment is slow, and clumps are left undisturbed for years, as lifting and dividing the rhizome sets them back. Removing a flowering stem takes the plant's only leaves and can kill or weaken it, so wild plants recover poorly from picking. Slugs and deer browse the foliage in spring.

Pruning

Trillium needs no pruning. The foliage is left to die back naturally so the rhizome can store reserves for the following year. Spent flowers may be left in place to set seed for slow natural increase.