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Blackberry root removal #878674

Asked July 25, 2024, 3:48 AM EDT

Hi, what is the best way to remove black belly roots? Without chemical. Is it solarization with plastic tarp? If so does heat goes deep enough? Is black tarp better than clear / opaque tarp? How long would it take ? Is it best to leave the tarp in winter too?

Jackson County Oregon

Expert Response

Here are some non-chemical ways to remove blackberries:
Mowing: Mow the vines to ground level, and then continue to mow back new sprouts that emerge. This method is best if the area is flat enough to mow with a lawnmower, and the vines grow quickly.
Digging: Dig out the blackberry crowns, making sure to get the entire root ball. However, digging out the roots once can spread the weed by fragmenting the rhizomes.
Cutting: Use loppers, a hedge trimmer, or a brush cutter to cut back the stems to about 1 ft from ground level. If the brambles are dense or have grown into shrubs or hedges, you may need to cut the stems in multiple places and pull sections away. However, cutting mature plants near the base may cause them to resprout vigorously, so you may need to repeat this process throughout the season.
Solarization is a non-chemical method that can be used to treat blackberry plants by covering infected areas with clear plastic during the hottest months of the year to kill fungi, bugs, and weed seeds. The process works by trapping the sun's energy in the soil, heating it to temperatures that can be lethal to many soilborne pests.
Here are some tips for solarizing blackberries:
Choose the right plastic: Clear plastic is more effective at heating the soil than black plastic. Thinner plastic (3 mils or less) conducts heat better than thicker plastic, but it's more likely to tear. In windy areas, use slightly thicker plastic (1.5–2 mils), and in small areas, use thicker plastic (4 mils or more). You can also try layering clear plastic on top of black plastic to increase temperatures.
Prepare the bed: Make the bed as flat as possible so the plastic is in close contact with the soil and there aren't any air pockets.
Choose the right time: Cover the soil during a hot period of the year when it will receive the most direct sunlight. In dry climates, the process usually takes 2–3 weeks during the summer.



Chris Rusch Replied July 26, 2024, 12:56 AM EDT
Thank you very much Chris for the instruction.

What is the root ball? Is it the source? Of all roots that are growing from?

Also I did not understand the below well. I found some multiple stems are growing from the ground. Is it inappropriate to cut all at the base at once?

I appreciate your clarification.

Masako

Cutting: Use loppers, a hedge trimmer, or a brush cutter to cut back the stems to about 1 ft from ground level. If the brambles are dense or have grown into shrubs or hedges, you may need to cut the stems in multiple places and pull sections away. However, cutting mature plants near the base may cause them to resprout vigorously, so you may need to repeat this 


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On Jul 25, 2024, at 9:56 PM, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied July 26, 2024, 5:31 AM EDT
The cutting section refers to large overgrown blackberry patches that need "taming" before treating by digging, covering, or mowing.
Yes the root ball is the source of all sprouts.
Chris Rusch Replied July 26, 2024, 11:16 PM EDT
Dear Chris,

Thank you again for your reply.

Can I ask one more question about removing blackberres?
I placed black tarp after mowing the BB, for a couple of months
Underneath the tarp, there are stems but very weak and white reddish. 
It seems this solarization worked in certain ways, although I see little BB still growing beside the tarp.


I would like to know how deep the solarization has affected.  I would like to know if this is enough for now.
I want to know if I should keep the tarp throughout fall and winter. 

If you could advise me, that'll be greatly appreciated.

Thank you very much.
Masako

PS. Is it OK to share the articles and your advise with my friends who have the same issue?

On Fri, Jul 26, 2024 at 8:16 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied September 27, 2024, 2:18 AM EDT

Soil solarization controls many of the annual and perennial weeds present in Oregon. While some weed species seeds or plant parts are very sensitive to solarization, others are moderately resistant and require optimum conditions for control; that is, tight-fitting plastic tarps, and high solar radiation. Solarization generally does not control blackberries because they often have deeply buried underground vegetative structures such as roots and rhizomes. You may have to leave the plastic in place longer.

https://ipm.ucanr.edu/PMG/PESTNOTES/pn74145.html

https://extension.oregonstate.edu/sites/default/files/documents/ec1594.pdf



Chris Rusch Replied September 27, 2024, 10:52 PM EDT
Thank you very much Chris for your reply. Yes it’s clear and helpful.  Is it ok to share this with my friends?

Masako

Sent from my iPhone

On Sep 27, 2024, at 7:52 PM, Ask Extension wrote:


The Question Asker Replied September 28, 2024, 1:00 AM EDT
Yes. Thank you.
Chris Rusch Replied September 28, 2024, 9:36 PM EDT

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