Spraying Roundup on Dormant Raspberries

Never spray Roundup on actively growing raspberry plants.

Never spray Roundup on actively growing raspberry plants.

Raspberries, members of the Rubus genus, grow on canes. They yield raspberries on new canes, called primocanes, that grow each year, leaving old canes behind. If they are left unpruned, the dead canes can form a weedy thicket. Raspberries grow in U.S. Department of Agriculture plant hardiness zones 4 through 9 depending on the cultivar.

Take Care

There are situations where you may want to use Roundup weed killer on or near raspberries. Roundup contains the active ingredient glyphosate, a nonselective, contact herbicide that kills all growing plants that it touches. When you spray Roundup, use eye protection and wear a long-sleeved shirt and trousers, socks and gloves. Do not inhale Roundup or get it in your eyes.

Roundup Before Planting

If you want to use Roundup to kill quackgrass (Elymus repens), Candian thistle (Cirsium arvense), field bindweed (Convolvulus arvensis) or other perennial weeds, spray Roundup at least one year before you plant the raspberries. If you cultivate these weeds instead of spraying them, their roots may break up and spread, growing new weeds. Do not spray Roundup on raspberries after you plant them.

Roundup Spot Treatment

Use Roundup with a wick applicator to treat problem weeds surrounding actively growing raspberries. Remember that Roundup kills the weeds you touch with the wick and other plants, including raspberries, whose roots touch the weeds you kill. In addition if the wind blows wet Roundup from treated weeds onto raspberry canes, it will kill the canes. A better solution for actively growing home garden raspberries is to pull weeds that appear among growing raspberries or surround the base of the canes with sawdust, straw or other mulch. If you apply mulch on clay or poorly drained soil, it can lead to phytophthora root rot or verticillium wilt.

Killing Weedy Raspberries

Roundup only kills plants that are actively growing. It does not kill dormant canes of raspberries that have gotten out of hand and become weedy. Neither will it kill dormant weeds surrounding the dormant raspberries. If you want to kill weedy raspberry canes, spray Roundup on them when they begin growing again in spring to destroy them.

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