I have a row of raspberries that are getting overgrown with grass. I had...

Asked October 15, 2014, 10:39 AM EDT

I have a row of raspberries that are getting overgrown with grass. I had initially tilled the area years ago and mixed in lots of compost and mulched the area when planted. Grass from the neighbors yard has crept in over time to the point where it grows all around the raspberries. I'm not sure what to do about this as I don't feel I can get rid of all the grass unless I dig up all of the raspberries and then eradicate the grass and replant the raspberry canes. Are there any other ideas besides this? Thank you!

Anoka County Minnesota

3 Responses

Keeping raspberries weed-free can seem overwhelming but there are a few things that should help. I'm assuming that the grass you refer to is quack grass (a perennial) or other grass that spreads by underground rhizomes. Sadly, tilling to remove this type of grass will only multiply the plants as each little piece of the rhizome root that has been broken off will then become a new plant. When hoeing, keep the hoe very close to the surface, just cutting off the plant itself, eventually, the rhizomes will die if there is no leaf surface for photosynthesis.
There are several chemicals approved for use with raspberries: Casoron 4G (grassy weeds and some broadleaf pests like Canada thistle), Poast, Princep and Suflan.
Also, a newer one on the market is Matrix which has good preemergence and postemergence activity on most annual broadleaves and grasses. For raspberries and blackberries, Matrix may be applied to plants established at least one year.
If you do decide to remove the raspberries, be aware that you may need more than one application of Round-Up as it only works on actively growing plants and up to 95% of the lateral buds on the rhizomes are dormant! I'm afraid that it's too late in the season to use RoundUp effectively.

Always be sure to follow label directions, as inappropriate timing of application can wipe out a crop.

For more information about growing raspberries: http://www.extension.umn.edu/garden/yard-garden/fruit/raspberries-for-the-home-garden/

Hi Faye, sorry to take so long to respond and thank you for the information. I just wanted to make sure to clarify something in your response. You mentioned that if I have established plants of at least one year I can apply Matrix on them to kill the grass? So I can spray around the raspberry canes when the grass starts growing again in the spring and the chemical will not affect the raspberry plants? I hope I'm making sense with my question. Thank you again!

I am sorry but Faye is not available at this time. I looked up Matrix and this is what I found:

Controls Grass and Broadleaf Weeds in Permanent Crops, Potatoes, and Tomatoes

DuPont™ Matrix® SG herbicide delivers contact and extended soil residual control of grasses and broadleaf weeds, including glyphosate-resistant marestail/fleabane, in tree nuts, stone/pome fruit, grapes, potatoes, citrus and tomatoes.

Matrix® SG is absorbed through the roots and foliage, rapidly inhibiting the growth of susceptible weeds.

It then delivers long soil residual control of mallow, marestail, fleabane, kochia and quackgrass with preemergence partial control of dandelion, lambsquarters, yellow nutsedge, prostrate pigweed and nightshade species. Matrix® SG can be tank mixed with other labeled partners to add contact activity or broaden the weed control spectrum. When mixed with a burndown herbicide, Matrix® SG improves the contact activity of the tank-mix partner on labeled species

I don't know if this herbicide is available to the general public but you can check with your local garden center. However, I am nervous about using this type of herbicide. I had the same problem you describe with my raspberry patch two years ago. I dug out the plants (they were becoming overcrowded anyhow) and planted the ones I decided to keep in a new location. This gave my plants a chance for fresh nutrients. This year I had the best crop I have had in several years. That gave me a chance to dig out the grass in the old area, then Round Up the remaining grass that came up that year. This year I planted tomatoes in that area, which also did well without the competition of grass roots.