White Snakeroot is an attractive fall-blooming native that enjoys part shade and thrives in woodland soil. This enthusiastic spreader reseeds prolifically and can form beautiful colonies that light up shady areas, especially if the soil is rich and moist. With an erect habit of 2′-4′, it generally does not require staking and plays well with other natives. The panicles of white flower clusters are an attractive late season food source for many bees, butterflies, and moths. Though often found growing naturally in places where it is sheltered from the hot summer sun, it is adaptable to various growing conditions. Due to the fact that this plant contains the toxin tremetol, it is not advisable to plant it where cattle or horses may graze (see Noteworthy Characteristics).
Other Common Names: Deerweed, Deerwort-Boneset, Milk-Sickness Plant
USDA Zones: 3 – 8
Life Cycle: Short-Lived Perennial, Perennial
Height: 2.00′ – 4.00′
Spread: 2.00′ – 4.00′
Sun: Part Sun – Shade
Soil: Clay, Loam, Rich Woodland Humus
Moisture: Medium-Wet, Medium, Medium-Dry
Bloom Time: July – October
Bloom Color: White
Uses: Naturalize, Rain Garden, Woodland Garden
Native Range: BONAP Map
- Contains tremetol, a toxin that can prove fatal to cattle or horses if consumed
- Associated with “milk sickness” which resulted in the death of Abraham Lincoln’s mother in 1818 (rare in the modern dairy industry)
- Spreads enthusiastically by seeds and rhizomes, especially in disturbed soil
- Grows well among other natives and can make a nice “filler” plant
- Has strong branched stems that don’t require staking
- Blooms late in the year around the same time as goldenrods and asters
- Long bloom time; visited by bees, butterflies, and moths
- Generally avoided by mammalian herbivores (deer, rabbits, etc) due to bitter foliage
- Black Walnut juglone tolerant
- A variety of caterpillars utilize the foliage for food
- Flower clusters resemble Boneset (see images below)
- Host plant for : Schizomyia eupatoriflorae, a small midge fly that specializes on White Snakeroot buds. Liriomyza eupatoriella, a species of fly whose larvae (leaf miners) feed on leaf tissue by mining tunnels in the foliage.
- Nectar plant for: Bees,Wasps, Moths, Butterflies, Flies
- Food source for: Harmostes fraterulus, a scentless plant bug that feeds on the flowers
- Seeds for over-wintering birds
Relatively disease and pest free.
PLEASE NOTE: Like all native plants, White Snakeroot is an important food source for many creatures. Some years they may be more affected by insects than others. However, these insects provide essential food for birds and other wildlife as part of a balanced, intricate food web. Instead of reaching for pesticides at the first sign of leaf damage, consider grabbing your magnifying glass or binoculars and observe what visitors are frequenting your amazing native plant!
A CLOSER LOOK
In order to provide the maximum benefit to pollinators, it is best to plan for a succession of blooms. This ensures that as one species fades, another begins to blossom. In this way, a constant source of nectar and pollen is provided from spring through fall. The following natives enjoy similar growing conditions to Ageratina altissima:
- Jewelweed – Impatiens capensis
- Goldenrod – Solidago spp.
- White Turtlehead – Chelone glabra
- Virgin’s Bower – Clematis virginiana
- Ironweed – Veronia spp.
- Fringed Loosestrife – Lysimachia ciliata
- Asters – Symphyotrichum spp.
- Wingstem – Verbesina alternifolia
- Tall Meadow Rue – Thalictrum pubescens
- Cutleaf Coneflower – Rudbeckia laciniata
- American Germander – Teucrium canadense
- Hollow Joe Pye Weed – Eutrochium fistulosum