Weeds or not?

Asked June 10, 2014, 4:39 PM EDT

We just moved here and are working on cleaning up our flower bed. Any idea if the large plants and the grassy-looking plants in the attached picture are weeds, or something we should keep? (I've been told the little plants toward the edges are definitely weeds.)

Also, we have some large, extremely thorny weeds (poked right through my heavy-duty garden gloves!) that I have tried to remove, but haven't had much luck getting the roots out. There are more I need to get rid of. Any idea what they might be, or they will come back if I don't dig the whole root out?

Burleigh County North Dakota

3 Responses

I am not sure what the red-stemmed plants are. They remind me of bee balm (bergamot, monarda). Are the stems square? This would confirm it. The silver-dusted weeds along the house are lambsquarters, a common weed. The spiky plants appear to be chives or wild garlic. You may want to snip off a leaf and smell it. The extremely thorny weeds are probably thistle. Canada thistle and bull thistle are among the common types. To confirm this, I would go to Google Images and type in the keywords "thistle Canada bull".Thistle is a perennial weed with an extensive root system. You can keep pulling the plants out, but you are not likely to get the entire root system. In these cases, we are usually better off using a herbicide. I would apply glyphosate (Round-up). This will kill all vegetation so do not spray it on any desirable plants. You could use a hand-trigger spray bottle, paint brush or a sponge to dab the leaves with the weed killer. You should start seeing results within a week. The most effective time to use Round-up will be in fall when the thistle will naturally absorb the chemical and send it to its roots as it ships its nutrients down to the roots to prepare for winter. I can share the photo of the red-stemmed plants with my colleagues and get back to you. Please contact me directly at my e-mail: tom.kalb@ndsu.edu and I can get back to you. Thanks!

Thanks for the input! I've send you an email with some more pictures and some follow-up questions.

Thanks. I'll respond via e-mail.- Tom