How to Tell If Roundup Killed Plants


Roundup is a non-selective herbicide that will kill any type of plant it comes in contact with. Roundup is a post-emergence herbicide, meaning it will only kill plants that have emerged through the ground, via their leaves and root system. Ungerminated seeds will not be affected by Roundup and must be sprayed when they become plants. Typically, Roundup is used to kill weeds (annual and perennial), woody brush and trees.

Step 1

Examine annual weeds two to four days after application. The weeds will begin to wilt.

Step 2

Examine perennial weeds one week after application. The leaves will begin to wilt, though it may take longer for some perennial weeds to show this first sign.

Step 3

Look to see if the plant has turned color. The plants will begin to turn yellow, then brown. If new weeds, or shoots from the plant, emerge in the same area, a second application is necessary.

Step 4

Inspect woody brush and trees seven days after application. Brush and trees should show signs of wilting and foliage discoloration.

Step 5

Look for signs of new growth, from seeds or underground shoots, around the brush or trees. If new growth is present, apply Roundup to the new growth.

Step 6

Remove weeds, brush and trees once the plant is dead and no new growth emerges. Remove them by hand or rototiller.

Tips and Warnings

  • Do not apply Roundup on a windy day, as the wind will carry the herbicide to other plants.

Things You'll Need

  • Rototiller (optional)


  • Texas A&M University: Roundup Label

Who Can Help

  • University of Minnesota Extension: Weed Control in Lawns and Other Turf
Keywords: Roundup plant effects, results of Roundup, post emergent herbicide

About this Author

Sophia Darby is a former professional hairstylist who has spent the last six years writing hair-related articles for both online and print publications. Her work has appeared in Celebrity Hairstyles Magazine, as well as multiple websites.