Thursday, March 20, 2008
Blame it on moles, or the drought, or worms, or leaky pipes ...
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
Or send an e-mail. Answers will be given only in this column. Please don't send pictures or samples.
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Q: I was walking over my yard in Rocky Mount and I noticed a lot of dead grass in places. Also, there are humps in my yard like there are moles in there. I know the winter had some very cold days and our summer was very dry. The guy that mows my yard mowed a little bit closer because I asked him to. Could that have caused the humps that look like mole tunnels? He didn’t mow one month because it was so dry. Please help me and recommend something I can do.
A: The lower mowing last fall should not have caused those humps in your yard. If your grass is bluegrass or fescue, the two most common lawn grasses in the Roanoke region, these grass types can endure shorter mowing in the fall. That's a good technique at that time of year because it lets in more sunshine and fall warmth in to the base of the grass plants.
The best way to find out if those humps were caused by moles tunneling through the soil is to stick a round-point shovel straight down into one or more of the humps when the ground is damp to see what’s there. Mole evidence will be either an underground cave or tunnel.
If mole activity is found, eliminate the moles first before flattening raised places with a lawn roller when the ground is damp. Mole elimination can be done using patience, persistence, and either mole baits used according to package directions or mole traps used only as directed on the safety and use instructions. Mole poisons containing the ingredient found naturally in caster beans have shown good results.
Success with either mole elimination method might require identification of regularly-used mole tunnels. Mark the humps with colors or markers before pressing them flat and then looking the following day to see which humps are “up” again. Success in mole elimination is indicated when no new tunnels or humps are seen.
Humps might contain only pencil-sized holes, which are a sign of earthworm activity. Earthworms are beneficial in the soil, but their humps can indicate that worms have been driven up to the upper layer of soil by drainage problems or other low-oxygen problems down deep where they normally stay.
Leaky drain lines could cause similar humps. Check those pipes.
Such soil constriction could have happened during last year’s drought followed by heaving during the winter temperature changes. If that is the case, simply flatten the humps by using a lawn roller over damp ground.
The dead grass you noticed in your lawn is probably composed of winter weedy grasses that have died at the end of their short life cycle. It could also be patches of warm season grasses that are dormant but will turn green when the soil and air during both day and night turn warm.
Rake out dead grass patches now and avoid the temptation to fertilize the lawn early this spring. Wait until after the good grass has slowed down its rapid spring growth, and then apply a turf fertilizer containing a major amount of slowly released nitrogen.
Probably the most important thing that you can do this year is to tell your lawn service to mow your lawn high -- 2 ½ to 3 inches. The grass should be mowed frequently enough so that no more than one-third of the grass height is removed at one time.
Q: With this funny weather here in central Virginia, when is a good time to move some “knockout” bush roses and an old climber rose in my yard to a better location? I used to think that roses should be transplanted while they were still leafless, but these have made leaves already.
A: With the abnormal weather here in Virginia, soil warmth but not heat is likely more important for transplanting this year than rose dormancy. I‘d suggest transplanting the roses just as soon as nighttime chills between warm spring days allow the rose soil to warm up somewhat so that rose root recovery will occur right away.
