I have some weeds that keep coming back in my 'blue rug' junipers. I reasearched it a little and found that pre-emergent weed killers are practical, but I am not sure which ones are safe to use on 'blue rug'. Please enlighten me concerning what is safe and what is not when it comes to 'blue rug' and pre-emergent weed killer.

  • 1
    What kind of weeds? Grasses,dandelions,vetch?
    – kevinskio
    Commented Jun 3, 2012 at 14:00

2 Answers 2


In this context, I use oryzalin, benfluralin, or dithiopyr based pre-emergent herbicides. Use according to the instructions on the product label, and be aware of possible contamination of groundwater.


Pre-emergents do not affect existing plantings. They do prevent seeds from germinating. Hence, they would prevent annual grasses from eating your Junipers alive. I use Preen for this purpose.

It is a also very effective against the rapacious annual Japanese stilt grass, which is a noxious invasive exotic weed afflicting the Southeast.

  • pre-emergents prevent seed germination. They are not toxic to existing plants. Commented Jun 3, 2012 at 14:18
  • Yeah I don't see what question you are answering with "No", I want to up vote the preen bit. Commented Jun 15, 2012 at 13:58

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