Thursday, March 27, 2008
Drying out moss
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
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Q: I have moss growing up close to the house that faces south and doesn’t get a lot of sunshine due to mountains that don’t let the full power of the sun to penetrate. I have tried a lot of things but now see moss creeping up onto the foundation blocks. I scraped it all off last year but it is returning. Is there something I can put in the lawn to deter the moss growth? What solutions can you give me for getting the mold off the foundations blocks?
A: There is a long list that goes from pH problems to shade to limited air circulation. Reduced penetration of the sun’s power is only one possibility. The fact that the moss has crept from your lawn onto the foundation blocks tells me that dampness and water retention are likely involved.
Renting a core aerification machine and plugging 1-½ inch deep holes in the soil adjacent to your house will work to improve drainage in that soil and thus make the soil less attractive to moss growth. I would do this before calling garden centers or hardware stores that sell lawn care products to find a commercially prepared bag of “lawn moss control” granules. This kind of product might be formulated with a turf fertilizer type, which would not be helpful to a bluegrass or fescue turf at this particular time of year.
I don’t know of a solution that will get the moss off your foundation blocks. Dead or living moss will require scraping. I suppose that moss herbicides that are labeled for moss control in ponds might help some.
The fact that moss lives on the blocks means that the surface of the blocks holds moisture. Masonry sealer or block paint would eliminate the porosity of the blocks and make the surface unsuitable for future moss growth.
To prevent a repeat appearance of moss growing on the soil, take time to investigate any source of dampness in the area. Re-direct sources found, such as a down spout. A lack of air circulation in that area might be remedied by pruning trees and shrubs that block the breezes.
Q: I’m not quite sure about the name of the ornamental grass that I have a question about as the new shoots of this grass come out around the outside, after the grass has been cut to about 8 inches. Is it possible to burn the remainder so that the sun can come through and the grass will grow from the center and out to edges?
A: The ornamental grass you describe is pampas grass, which makes new growth as you described with fresh blades emerging around the outside of a dead center. This outer new-growth trait is a rule of nature and can’t be changed.
Damage might occur to the grass crown as a result of the heat of burning. New growth will not come from the center. Burning off pampas grass top growth would not work in the fashion farmers burned off their fields years ago to prepare them for a new growing season.
Pampas grass’s dead center reminds me of the dead heartwood in tree trunks: each year’s new growth in the outer portion of the trunk produces their annual growth ring in the process.
Q: I was having a problem with oak seedlings coming up everywhere in the mulch from acorns under some big oaks in my landscape. I installed landscape fabric under the mulch there, and that took care of the oak seedling problem. However, the periwinkle there doesn’t spread and fill in with the fabric under the mulch. Can I have the best of both?
A: Try cutting holes in the fabric into which you can plant new periwinkle plants.
