Blackberries take persistance and time to control

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Last Updated: 
July 29, 2005

Ripe blackberries on the vine.CORVALLIS - If you maintain a yard on the west side of the Cascades you probably are well aware that blackberry vines are hard to kill. Unfortunately, these vines are very aggressive in the way they grow. If not controlled, blackberries can soon take over broad areas of your property.

One reason blackberry vines are so difficult to control is that established plants spread by nodes - or small underground buds - that grow off established blackberry vine roots, explained Jed Colquhoun, weed scientist with the Oregon State University Extension Service.

"This makes it hard to kill the vines by digging them up," said Colquhoun "No matter how much of the plant you remove, you'll miss a few nodes that will soon develop into new vines."

Like other berry-bearing vines, blackberry vines are able to root from the tips of stems at certain times of the year. In early autumn, near the end of the spring-summer growth period, long vines arch over and wherever they hit the ground the tips of the vines take root, creating new plants that will sprout up the following spring.

So how do you control a plant that has so many ways to survive?

Cut back the vines back to ground level, especially during the spring when the plant is most actively growing. Removing the aboveground part of the vine keeps the plant from manufacturing the sugars it needs to sustain vigorous growth. Cutting vines back continually will eventually kill the plant, although it may take some time.

Digging up vine roots will provide some control, but you probably won't eliminate all of the plant.

For home landscapers looking for chemical controls, Colquhoun suggests using glyphosate or compounds containing 2,4-D or triclopyr. The timing of application is very important and must be strictly observed for maximum effect. Glyphosate, for example, must be applied in the fall or it will be ineffective. Products intended for homeowner use that contain 2,4-D or triclopyr often have the words "brush control" or "blackberry killer" in the trade name.

Colquhoun urges users to observe all label instructions and restrictions whenever handling and using any pesticide.

Author: Carol Savonen
Source: Jed Colquhoun