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Soil Issues/Killing weeds through river rock

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Expert: James L. Crowder - 7/7/2009


Question
My sister has river rock surrounding her pool and back deck. Just spent three days pulling weeds. Do you know the best way to get apply a weed killer so it penetrates the soil through the rocks? The soil is hard and dry. Should I water first, then spray the weed killer then water again?

Answer
Hi Karen, Glyphosate is a non-selective herbicide you can spray over the rock and kill anything there.  If does nothing to the soil, so weeds can come back by seed or by spreading into the area.  You could add a pre-emerge like Dimension to stop seeds for 90 days or so, but you may still have grass spreading into the area.  Spraying once every couple of weeks on anything green should keep the area clear.
Or, you can spray Pramitol over the area and sterilize the ground for a year.  Nothing will grow there.  Grass may creep out on the rocks, but it will not root in.  Pramitol would be my first choice. You'll have to use enough water to get the product to the soil surface, but use caution not to flood the area that may carry it into desirable plants.  I use it in my rock walkways that are bordered with zoysia with great success.
Jim

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Volunteer

James L. Crowder

Expertise

I can answer questions about soils, soil amendments, drainage and proper planting. I can answer questions about insects and diseases, weed control, etc. I have extensive background in homeowner labeled pesticides (insecticides, herbicides, fungicides, etc.) and their proper use. I can also answer questions about the growing requirements of specific plants.

Experience

I have 40 years experience in the lawn and garden business split fairly evenly between the retail nursery business and wholesale distribution of consumer lawn and garden products. From 1990 to 2000 I co-hosted a weekly call-in talk radio program in Memphis, TN.

Organizations
Garden Writers Association

Publications
Green Thumb Magazine - out of print

Education/Credentials
40 years of learning everday.

Awards and Honors
Past president of the Memphis Horticultural Society. Past president of the Memphis Bonsai Society. Memphis Horticultural Society 2008 Horticultural Excellence Award

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