Friday, June 20, 2008
Determine the right strategy for repelling moles or voles
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.
Recent columns
Q: The voles/moles in my small flower garden love my hosta. I would like to plant some chrysanthemums in the same garden. Will they get eaten also?
A: Yes, I understand that moles and voles can eat parts of chrysanthemum plants. However, there are damage control strategies for both critters.
Moles eat meat and most of their damage to plants is making raised areas in the soil, creating tunnels that mice and other wildlife can use, and allowing air to dry out roots of our desired plants. Voles, on the other hand, are like field mice. They can eat plant parts either above or below the ground and some of them do use tunnels created by moles below ground or man or nature allowing dense grass or other vegetation above ground.
So, to protect your young chrysanthemum plants, look for damage done to your hostas and devise your strategy based on what you find. Appropriate repellents might be available at some hardware stores or garden departments. Cut and remove dense plants, weeds, and grass near your flower garden. Physical methods to deny access to your young chrysanthemum plants work as protection against both moles and voles. Bury vertical rings of 1-inch mesh chicken wire around chrysanthemum plant root systems to prevent digging and eating there and extend those rings above ground for several inches to hinder wildlife feeding on stems and leaves. Contact your local Cooperative Extension Service for more details.
Q: Our backyard landscapes on the upper part of the fairly steep slope behind our houses are being invaded and taken over by Crown Vetch planted on the slope. I know that Crown Vetch is used along highway slopes along with grass to prevent erosion. I love its pink blooms at this time of year. What can be done about this Crown Vetch invasion? Even though this slope and the development have been here for several years, we didn’t notice this problem in prior years. The slope looks weedy now. Also, I’ve read that Crown Vetch attracts snakes and rodents. Is that true?
A: Stopping an invasion of Crown Vetch from taking over landscape plantings and grass areas can be expensive in terms of time needed, chemicals and certified applicators hired to spray, mowings, and paid grounds maintainers; an on-going battle; and frustrating at times.
Crown Vetch grows as a perennial that does a good job as a companion to grass for erosion control, as you noted. It is also good for the soil, since it is in the plant category called “legume”, which means that it has the ability to fix the nutrient nitrogen in the soil. However, it is slow to grow from seed and can take 3 years to grow enough to bloom. This could explain why you didn’t notice the Crown Vetch in prior years.
In those landscape plantings on your slope, hand pulling of Crown Vetch is the only means to get rid of this invader. The Vetch will come back in, though. It might help to create a wider border around hillside plantings and cover this border with 4 inches of shredded organic mulch. Please be sure that mulch is not that deep close to any landscape plant.
According to an information publication from the Virginia Department of Conservation and Recreation, Crown Vetch invasion can be stopped or slowed by mowings and careful use of the non-selective plant killer active ingredient glyphosate. Caution must be used when applying plant killers with glyphosate, since as a non-selective chemical, it can injure or kill any actively-growing green plant, including grass, that is contacted by glyphosate. Even though many glyphosate products are not restricted chemicals requiring state pesticide applicator’s license, any person paid to apply any product must be certified with a current state pesticide applicator’s license.
The purpose of mowing to control Crown Vetch is to weaken the invader naturally by starving it by continually removing its sugar producing leaves. During times of occasional rains, this means that grassy areas on that slope near landscape plantings should be mowed or weed whacked once every 2 weeks.
I too have heard that Crown Vetch does attract snakes and rodents. This makes sense, since dense Crown Vetch vines and unmowed grass planted together for erosion control provides attractive shelter for low wildlife critters.
