The Q&A Archives: SAFE Weed Killer Before Mulching Butterfly Garden

Question: Have to use a systemic weed killer before laying down mulch, maybe rubber mulch - heard it was good. Anyway, plants are already planted but had a problem w/stumps growing back so had to stop midstream and not mulch for a month. It's now planted w/beautiful Home Depot Roses, including Knock-outs (but love the Jackson Perkins!) and it's a butterfly garden with butterfly and hummingbird plants. What can I use that will NOT HARM the butterflies, larvae, etc.? Diatamateous (sp?) earth maybe? IF I have to use something, it has to be safe or I'll just be pulling the weeds myself and that'd be a waste. Also, those little beetles in the ground - slugs, right? Heard diatamateous (sp?) earth would kill them too if I put on ground...true? Thank you so much. I try to find the answer but this one's hard! Home Depot's the best! Teri

Answer: Teri,

I apologize for this delayed reply to your gardening question and hope it is still helpful to you.

Herbicides will not harm your beneficial insects. I suggest you use a product with glyphosate (Roundup is one brand and just apply it to the foliage of the plants you want to kill. If they are very woody and strong it may take more than one attempt. The glyphosate breaks down fairly rapidly and won't harm things you plant where it was used. If your pest is truly slugs the least toxic products are the bait Sluggo which is made of iron and phosphorus or Green Light's Bug and Snail Bait made from Orthoboric acid another ingredient considered among the least toxic.

Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!

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