Will Removed Trees’ Roots Continue to Grow?

From the Help Desk of the
UC Master Gardener Program of Contra Costa County 

Client's Request:  I'm removing some large ash and elm trees to the ground and will be grinding the trunk below ground surface as well. We won't be removing any of the remaining tree roots although they both appear to have extensive root systems. My question: “Will the remaining unremoved ash or elm trees' roots continue to grow once the trees have been cut to the ground?

UC MGCC's Help Desk Response: Thank you for contacting the UC Master Gardener Program of Contra Costa County regarding the remaining roots after removal of your large trees. 

Based upon our research about invasive tree-root problems, there seems to be no real difference between ash or elm trees in the strength of their roots. Many other types of trees' roots are much more aggressive.

Regardless, these trees do have extensive roots that will try to live on reserve sugars for awhile. The roots will send up shoots as long as they are able, about a year or so, and if the leafy shoots find sun, they will try to grow. However, without sun, water and an unimpeded growing space, the weakened roots will eventually fail. To eliminate the trees from your garden, do not allow the shoots to succeed as that will create new sugars via photosynthesis from sunlight exposure.

You will have to be vigilant for a year or two, cutting back the shoots and sprouts as they pop up. Those severed roots under the foundation & walkways cannot live after their food reserve is gone.

Below is a a link to the University of California's Pest Note about woody weeds - which includes tree roots. It explains various methods to keep those tree shoots down and out.
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74142.html

Please do not hesitate to contact us again for garden assistance.

Help Desk of the UC Master Gardener Program of Contra Costa County (MKW)
Don't miss our 2016 Great Tomato Plant Sale:
http://ccmg.ucanr.edu/EdibleGardening/GreatTomatoPlantSale/

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Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (//ucanr.edu/blogs/CCMGBlog/).