Tough Question - Planting Trees and Shrubs in Heavy Stump Grinding Material - Ask Extension
A huge oak tree was recently removed from county ROW in front of our home. A commensurately huge stump was left behind. The county performed admirabl...
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Tough Question - Planting Trees and Shrubs in Heavy Stump Grinding Material #784724
Asked March 21, 2022, 7:09 PM EDT
A huge oak tree was recently removed from county ROW in front of our home. A commensurately huge stump was left behind. The county performed admirably in grinding out the stump today. Despite taking much material away there is a good 4-5-6 inches in depth of material that has spread for a planned planting bed of skip laurel, rhodo's and azaleas and some grasses It will be beautiful! I gut tells me planting in the ground up oak material will not be suitable for plant survival. Plants/trees/shrubs need earth - soil. How best can I plant successfully without removal of all that oak material? it is a lot. I could go on top of the entire site with new soil of about 6 inches or more. Or, I could dig down through the oak material reaching good soil on a plant by pant basis of say 12 inch diameter per hole. Thought I should check in with the experts before I screw up and plant then suffer losses. Any great ideas?
Montgomery County Maryland
Expert Response
Wood chips like these can make an excellent mulch, so you can use them to top-dress planting beds or walking paths in any parts of the yard. (Don't put it on top of pre-existing bark mulch, though, just use it as the only mulch layer.) As you suspect, wood chips should not be used for planting into nor incorporated into the soil. In that scenario, the soil microbes that decay the wood will rob the surrounding soil of nitrogen that they need to feed on the wood, which would deprive any nearby plant roots of needed nutrients. (Adding fertilizer to compensate might work, but there is no way to tell how much would be needed, or when, so we do not suggest doing this as it could over-apply certain nutrients and harm soil health.) When chips are kept on the surface, the amount of nitrogen depravation in the soil below is negligible.
For planting in an area now covered with chips that are too cumbersome or voluminous to move elsewhere, simply push aside the chips where individual plants will be put so you can access the soil underneath for planting normally. (Don't layer soil on top of the chips.) Then, you can replace the chips as mulch around the new plants. While bark mulch should not be laid that thickly, wood chip mulch behaves a bit differently and evidence by other Extension research (such as from the author of the linked publication above) suggests that a layer this deep is not an issue for plant health. Plus, it will degrade over time and enrich the soil as it does.
Worst-case, if you still find that you have too big of a pile of wood chips to work with, see if neighbors or gardening friends in the area are interested in gathering and taking some for themselves. Arborist wood chips have gained quite the fan club in recent years as information like the publication above has been circulated, so you may find multiple people eager to take some off your hands.
Miri
For planting in an area now covered with chips that are too cumbersome or voluminous to move elsewhere, simply push aside the chips where individual plants will be put so you can access the soil underneath for planting normally. (Don't layer soil on top of the chips.) Then, you can replace the chips as mulch around the new plants. While bark mulch should not be laid that thickly, wood chip mulch behaves a bit differently and evidence by other Extension research (such as from the author of the linked publication above) suggests that a layer this deep is not an issue for plant health. Plus, it will degrade over time and enrich the soil as it does.
Worst-case, if you still find that you have too big of a pile of wood chips to work with, see if neighbors or gardening friends in the area are interested in gathering and taking some for themselves. Arborist wood chips have gained quite the fan club in recent years as information like the publication above has been circulated, so you may find multiple people eager to take some off your hands.
Miri
This is a reply to Miri - Thank you for the explanation. It helps a lot. Moreover, I apologize for my poor proof reading of my question. Very sloppy and embarrassing.
Howard
You're welcome.
