Nov. 16--Bunnies in children's books are cuddly and cute. Bunnies in the garden can be a serious source of aggravation, feeding on flowers, vegetables and other plants.
The problem doesn't go away with the waning of the growing season, says Pete Linsner, who is in charge of handling animal damage at The Morton Arboretum in Lisle. Rabbits remain active all winter, and with their summer food sources gone, they often turn to feeding on the twigs and bark of trees and shrubs.
Bark damage can kill these plants, Linsner says. Water flows between roots and leaves in the inner layers of the bark. If rabbits, voles, deer or other animals eat the bark all the way around a trunk, the flow is cut off and the tree or shrub dries out and dies.
"Fencing is the best way to protect trees and shrubs," Linsner says. He recommends wire mesh, such as chicken wire or hardware cloth, in a cylinder around a shrub. Make the cylinder wide enough to stand 1 to 2 inches out from the ends of the branches, so rabbits can't reach through to nibble them.
Be sure the seam in the mesh is securely closed, he says; rabbits can squeeze through openings as small as 2 inches. Anchor the fence well with fence stakes.
How high does the fence need to be? Most rabbits can't jump higher than 36 inches. But if there are several inches of snow on the ground, it gives bunnies a boost up, Linsner says, so it's best to make the fence higher in case there's a snowy winter.
He advises the same protection for young trees, which have thin bark. They are vulnerable for at least the first two or three years after they are planted. Older trees develop thicker bark that is hard to chew.
Gardeners are often advised to partially bury a fence around a vegetable garden so rabbits can't dig under it. That's not a good idea when protecting trees and shrubs, Linsner says: Digging would damage the roots of the plants, and it's not necessary, because rabbits can't dig in frozen ground.
Another option is fencing the entire yard or garden. For that to work, it's essential to have a rabbit-tight gate and keep it closed. To deter deer as well as rabbits, a fence needs to be 8 feet high, Linsner says.
Many gardeners try to hold off animals with spray repellents. They can help, Linsner says, but "it's a lot of work." Repellents need to be re-applied after every rain.
More importantly, a single potion won't do the job. A repellent works by scaring animals with an unfamiliar taste or smell; if they have a chance to get used to it, they will come to disregard it. You need to alternate several different repellents to keep them wary.
It's impossible to protect every bush in the garden, but if you have newly planted trees or shrubs, ones that have been chewed in past winters, or especially small or valuable specimens, now is the time to fortify them against hungry bunnies, Linsner says. Rabbits don't just feed in winter; they breed.
Botts is a staff writer at The Morton Arboretum in Lisle (www.mortonarb.org).
For tree and plant advice, contact the Arboretum's Plant Clinic (630-719-2424 or plantclinic@mortonarb.org).
