Invasive weeds this summer

Asked August 29, 2019, 5:28 PM EDT

I have had thousands of these weeds show up this summer in my 1000 sq ft, shaded backyard. They have displaced my sparse lawn. What are they and how do I control them?

Harford County Maryland lawns and turf weeds american burnweed shiso

1 Response

The main weed in your photos is Perilla frutescens, also known as Shiso or Beefsteak plant. It is an Asian plant used in cooking and medicine. It has escaped people's vegetable gardens and has invasive tendencies as you are seeing. (It is in the mint family).
It is an annual so it will die with frost, but you can see it is just beginning to flower so you want to pull it or mow it to prevent it from making more seeds.

Your third photo shows an American Burnweed. It will make fluffy seed heads soon so you should pull that too. Here is our page on it:
https://extension.umd.edu/hgic/topics/american-burnweed

This is the perfect time of year to plant perennials or renovate or over seed your lawn. Thickening it up with turf grass or other cover will limit what else can seed in. Mulch would help too.

If you are interested in that, here is our lawn information: https://extension.umd.edu/hgic/topics/lawns


Christine