White snakeroot

About

A native woodland wildflower that is poisonous to livestock, and through their milk, to people. In pioneer days it caused 'milk sickness' in people, which reportedly killed Abraham Lincoln's mother.

Also called richweed, white sanicle, fall poison, tremetol

How to identify it

Look for

Plants grow 2 to 5 feet tall with smooth stems and toothed, pointed-oval leaves in opposite pairs. From midsummer into fall, it carries flat, loosely branched clusters of tiny white flowers.

Where it grows

Shady woods, woodland edges, shaded pastures and shady garden beds.

When

Leafs out in spring and flowers from midsummer through fall (about July to October).

How it spreads

Spreads by seed and comes back each year from its perennial roots.

Most common in

What to do, gentlest first

Protect yourself first. Weed killers are a last step; always read and follow the label.

1. Keep animals out of shady pastures Prevent

   Move livestock and horses out of wooded or shaded pastures where it grows by midsummer. In gardens, wear gloves when working with it.

2. Pull after a rain By hand

   Pull plants when the soil is moist so the roots come out whole, ideally before seeds form in fall.

   Wear gloves and bag plants for the trash in grazing areas.

3. Spot-treat with dicamba or glyphosate Conventional spray

   In pastures and non-crop areas, dicamba-based products or a glyphosate spot spray can control it.

   Read and follow the label. Many lawn and brush herbicides also kill garden plants, so keep spray and drift off anything you want to keep. Follow grazing restrictions on the label.

Uses, wildlife and pets

For wildlife

Butterflies and bees use its late nectar and pollen, and songbirds eat the seeds.

Pets

Toxic to horses (ASPCA), with weakness, tremors, heart damage and trouble swallowing; the ASPCA does not list it as toxic to dogs or cats.