Pennsylvania Smartweed

 

 

This plant can reach a height of over 3 feet. The foliage of young plants is alternate and lance-shaped. Both sides of a leaf are purple and hairy on the upper surface. There is a membranous sheath (called an ocrea) that surrounds the stem at the base of each leaf. The stems are reddish purple with pronounced nodes. Mature plants have similar in appearance, though the hair on the upper surface of the leaf is absent or greatly reduced.

 

 

Some of the leaves may develop a purple blotch on the upper leaf surface. However, this is not a reliable diagnostic characteristic. Flowers are produced in late summer into autumn. They are white to pink and very small, but are clustered together on a hairy stalk, which makes them more visible. Smartweed is adapted to landscapes, nurseries, and agricultural settings.

 

Pennsylvania smartweed has a fibrous root system and a shallow taproot. Depending on the soil conditions, it is not always easy to hand remove. The proper use of mulch in ornamental plant areas also can effectively reduce this weed.

 

Herbicide options include the pre-emergenents:

 

 

Post-emergenent herbicides include:

 

 

Remember to always read the label for proper application sites and rates.