Ageratina altissima

White Snakeroot

$3.00 - $40.00

1/8 oz.
1/4 oz.
1/2 oz.
1 oz.

White Snakeroot bears clusters of small, foamy white flowers, often reaching 2 to 4 feet in height. Toothed, somewhat heart-shaped leaves drape elegantly from long stems. Blooming in late summer, this plant keeps its dainty blossoms well into the fall season, oftentimes past the first frost!  Fertilized flowers transform into fluffy tufts, and like miniature dandelion seedheads, they whimsically disperse seeds on the wind.  

Ageratina altissima grows best in moist soils in shade or partial sun. It is commonly found along woodland edges, near sheltered waterways, and in recently disturbed, shaded sites. Immediately after soil disturbance, its onset may seem overwhelming and weedy; White Snakeroot spreads by rhizomatous roots to form colonies and is a prolific self-seeder.  However, this plant does settle down once an area is established and will grow respectfully among other plants.   

The tiny white flowers attract a variety of insects including bees, butterflies, and moths.  A number of caterpillars are known to feed on the foliage, including the Ruby Tiger Moth caterpillar.

This plant is typically avoided by mammalian herbivores because of its bitter foliage. White Snakeroot contains the toxin tremetol which causes "the trembles" in cattle and other livestock. "Milk sickness" was a fairly common illness and cause of death for many 19th century pioneers, notably including Abraham Lincoln's mother. Pasture maintenance, not allowing livestock to graze in woods and near riverbanks, and modern dairy processes have made milk sickness cases very rare and typically treatable.

Formerly classified as Eupatorium rugosum

Ageratina altissima - White Snakeroot

Map Key

Present in state
Present but introduced in county
Present and native in county; not rare
Not present in state
Present and native in county; rare
Species extirpated (historic)
State or county listed as noxious
Present in state; exotic

This map shows the native and introduced (adventive) range of this species. Given appropriate habitat and climate, native plants can be grown outside their range.

3 Questions asked on Ageratina altissima

I'm wondering what the growing pattern for this plant is. I've had problems introducing certain plants into my all native landscape that then become very weedy or spread too aggressively. I'm not looking for docile plant that needs coddling, but I know my limits with aggressive takeover types!
White Snakeroot will come in strong on a newly disturbed shade or part-shade site, but it does not persist. So, if you are OK with lots of plants the first year, followed by just a few the next, I would say go for it.
Should I be concerned about the toxicity of this plant in the home garden?
Hi Mary, The White Snakeroot is known for milk sickness which occurred when cattle consumed the plant and then humans consumed the milk. You should not be concerned about this plant in a home garden.
I plan to plant white snakroot in a garden bed in hopes of better controlling invasive knotweed planted by a previous owner. Approximately how many seeds should I sow per square foot of the garden bed?
Hello Cassie, We recommend 100 seeds per square foot if you are seeding an individual species vs a mix of species. We would recommend to prep your site so that the White snakeroot has a better chance of thriving against an aggressive invasive. Native plants, even if they are aggressive in nature, typically do not stand against non natives as well if they do not have the upper hand from a prepped site. Some options for prepping your site can be found HERE. I hope this helps


Growing your own plants from seed is the most economical way to add natives to your home. Before you get started, one of the most important things to know about the seeds of wild plants is that many have built-in dormancy mechanisms that prevent the seed from germinating. In nature, this prevents a population of plants from germinating all at once, before killing frosts, or in times of drought. To propagate native plants, a gardener must break this dormancy before seed will grow.

Each species is different, so be sure to check the GERMINATION CODE listed on the website, in the catalog, or on your seed packet. Then, follow the GERMINATION INSTRUCTIONS prior to planting. Some species don't need any pre-treatment to germinate, but some species have dormancy mechanisms that must be broken before the seed will germinate. Some dormancy can be broken in a few minutes, but some species take months or even years.

Seed dormancy can be broken artificially by prolonged refrigeration of damp seed in the process of cold/moist STRATIFICATION. A less complicated approach is to let nature handle the stratifying through a dormant seeding, sowing seeds on the surface of a weed-free site in late fall or winter. Tucked safely beneath the snow, seeds will be conditioned by weathering to make germination possible in subsequent growing seasons.

To learn more, read our BLOG: How to Germinate Native Seeds

Dormant Bare Root Plants

We dig plants when they are dormant from our outdoor beds and ship them April-May and October. Some species go dormant in the summer and we can ship them July/August. We are among the few still employing this production method, which is labor intensive but plant-friendly. They arrive to you dormant, with little to no top-growth (bare-root), packed in peat moss. They should be planted as soon as possible. Unlike greenhouse-grown plants, bare-root plants can be planted during cold weather or anytime the soil is not frozen. A root photo is included with each species to illustrate the optimal depth and orientation. Planting instructions/care are also included with each order.

Download: Installing Your Bare-Root Plants

Potted Plants

3-packs and trays of 32, 38, or 50 plants leave our Midwest greenhouses based on species readiness (being well-rooted for transit) and order date; Spring shipping is typically early May through June, and Fall shipping is mid-August through September. Potted 3-packs and trays of 38 plugs are started from seed in the winter so are typically 3-4 months old when they ship. Trays of 32/50 plugs are usually overwintered so are 1 year old. Plant tray cells are approximately 2” wide x 5” deep in the trays of 38 and 50, and 2.5" wide x 3.5" deep in the 3-packs and trays of 32; ideal for deep-rooted natives. Full-color tags and planting & care instructions are included with each order.

Download: Planting and Care of Potted Plants

*PLEASE NOTE: we are a mail order nursery and have no retail facilities, but you may pick up your order if prior arrangements are made. Pick up orders are subject to **MN Sales Tax.

Shipping & Handling Charges

SEED $100.00 and under: $5.00
Retail SEED orders over $100.00 ship free!

Custom seed mixes or discounted seed sales over $100, add 5% of the total seed cost
(for orders over $1,000 a package signature may be required)

BARE ROOT and POTTED PLANTS $50.00 and under: $9.00
over $50.00: 18% of the total plant cost. (For orders over $1,000 a package signature may be required.)

TOOLS and BOOKS have the shipping fee included in the cost of the product (within the contiguous US).

**We are required to collect state sales tax in certain states. Your state's eligibility and % will be calculated at checkout. MN State Sales Tax of 7.375% is applied for orders picked up at our MN location. Shipping & handling charges are also subject to the sales tax.

Shipping Season

SEED, TOOLS and BOOKS are sent year-round. Most orders ship within 1-3 business days.

BARE ROOT PLANTS are shipped during optimal transplanting time: Spring (April-May) and Fall (Oct). Some ephemeral species are also available for summer shipping. Since our plants are field-grown, Nature sets the schedule each year as to when our season will begin and end. We fill all orders, on a first-come, first-serve basis, to the best of our ability depending on weather conditions beyond our control.

POTTED PLANTS (Trays of 32/38/50 plugs and 3-packs) typically begin shipping early May and go into June; shipping time is heavily dependent on all the species in your order being well-rooted. If winter-spring greenhouse growing conditions are favorable and all species are well-rooted at once, then we ship by order date (first come, first serve). We are a Midwest greenhouse, and due to the challenges of getting all the species in the Mix & Match and Pre-Designed Garden Kits transit-ready at the same time, we typically can't ship before early May. Earlier shipment requests will be considered on a case-by-case basis.

*We are unable to ship PLANTS (bare root or potted) outside the contiguous US or to CALIFORNIA due to regulations.


We ship using USPS, UPS and Spee Dee. UPS and Spee Dee are often used for expediting plant orders; they will not deliver to Post Office Box numbers, so please also include your street address if ordering plants. We send tracking numbers to your email address so please include it when you order.



Germination Code
Life Cycle
Short-Lived Perennial, Perennial
Sun Exposure
Partial, Shade
Soil Moisture
Medium-Wet, Medium, Medium-Dry
2 feet
Bloom Time
July, August, September, October
Bloom Color
Deer Resistant
USDA Zones
Catalog Code