Mulch

1. Q. I know that you are a great proponent of the benefits of mulching around fruit trees with organic material. Would this be as beneficial for shade trees also?

A. Yes! A recent report from California reports greater tree growth where the trunks are turf-free. They reported that young nonfertilized slow-growing trees like Southern Magnolia may triple in height if a 2 X 2 foot turf-free area is maintained around the trunk. If the clean area is 10 X 20 feet, the height growth may increase 6 times. Trunk diameter can also increase significantly - - from 2.5 to 4 times the trees with turf around the base. There is of course, a different response with other tree species. It goes without saying, keeping the turf competition from young trees will mean fewer tree injuries from mowing equipment.

2. Q. Why are leaves of pecan and live oak trees unacceptable to use in gardens and as a mulch?

A. Leaves of pecan and live oak trees are acceptable to use in gardens and as a mulch. I have been hearing misinformed people give reasons not to use pecan leaves. Most indicate these leaves put too much acid into the soil. This reason is WRONG. First, all organic material produced from an alkaline growing condition is mainly alkaline. Since pecan trees are growing in the area's alkaline soil types, unfortunately, the decomposition product will be alkaline. Even if this were not true, pure sulfuric acid can be applied to the soils in this area and the soil will neutralize the pure acid without significant alteration. This occurs because area soils are so basic (alkaline) and extremely buffered (resists change). Five pounds of sulfur, the amount recommended for 100 square feet of garden space, releases 15 pounds of pure sulfuric acid. It would take the decomposed remains of several semi-trailer truckloads of leaves, regardless of the type, to produce that much sulfuric acid. Our soils need all the acid that they can get. If pecan leaves produce more acid that is one major advantage to using them -- BUT THEY DON'T.

3. Q: I use the mulch from the Bitters road brush site. I have been told that there is a possibility of spreading Oak Wilt to my trees. Is this true? If the mulch can spread Oak Wilt, is it advisable to use the mulch at all (as on my vegtables).

A: You cannot spread Oak Wilt from tree trimmings. I would not use the mulch on the vegetable garden since it is too course; use it around trees and shrubs. Use shredded leaves and grass clippings in the garden and add extra (4 pounds rather than 3 pounds of 19-5-9 per 100 square feet) fertilizer when adding non-decomposed organic matter.


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