Country Selector
Please enter a valid location
Identifying and controlling purple deadnettle
Purple deadnettle, a member of the mint family, is a winter annual weed with purple-tinged leaves, pointed tips and purple-red flowers. Because of its close resemblance to henbit, purple deadnettle is often misidentified. Proper identification is important, as it can serve as an alternate host for the destructive soybean cyst nematode (SCN).
The difference between purple deadnettle and henbit
Since purple deadnettle and henbit have similar appearances, it’s crucial for farmers to know what to look for when scouting their fields.
Identifiers of purple deadnettle:
- Leaves: Opposite, with pointed tips and a purple tinge; grow on short or long petioles depending on where the leaf is located on the plant
- Flowers: Purple-red; grow in clusters of three to six in the upper leaves; typically flower from April through October
- Stems: Purple-green and square; covered in downward-pointing hairs; tend to branch at the base
Identifiers of henbit:
- Leaves: Hairy with rounded teeth; upper leaves clasp the stem
- Flowers: Tubular with two lips; pink to purple; flower from March through November
- Stems: Square-shaped; green but may turn purple with age; downward-pointing hairs
A host for SCN
Purple deadnettle can host SCN even when soybeans are not in the field. SCN can infect the fibrous roots of the weed and complete its life cycle, reproducing even without soybeans present. Of six winter annuals proven to be alternative hosts for SCN, purple deadnettle is among the strongest. Farmers must take steps to control purple deadnettle not only to reduce weed populations but also to limit the threat of SCN.
Controlling purple deadnettle
Once the weed is properly identified, farmers should work with their local ag retailer or crop protection representative to decide which weed control practices and products best fit their operation. Options include:
- Using tillage as a management tool. Tillage can reduce the number of weeds present and should be considered in addition to a herbicide program.
- Applying a burndown herbicide. Elevore® herbicide can be added to a burndown program to deliver effective control of purple deadnettle without regrowth.
- Using preemergence herbicides. Following burndown, a preemergence herbicide application will help ensure weeds are controlled. Tank-mixed with an appropriate rate of 2,4-D or glyphosate-based product, Sonic® Boom herbicide offers additional control of purple deadnettle.
For more information, farmers can visit Corteva.us or contact their local Corteva Agriscience representative.
Elevore® and Sonic® Boom are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.
The More You Grow
Find expert insights on agronomics, crop protection, farm operations and more.