As you putter around the garden at this time of year, you may notice that some shrubs aren’t what they used to be. They’re shorter. The reason? It may be bunnies.
“When a shrub is snipped off within about 2 feet of the ground, rabbits are usually the culprit,” said Sharon Yiesla, plant knowledge specialist at The Morton Arboretum in Lisle. “The stems will be clipped neatly at a 45-degree angle. Rabbits are very tidy.”
The good news is that most shrubs will recover from an occasional rabbit pruning. “They will grow new stems to replace the ones that were eaten,” she said.
The bad news is that a spring-flowering shrub, such as viburnum, forsythia, or deutzia, likely won’t bloom after being sheared by rabbits. The flowers of those shrubs emerge from buds that were formed last year and carried through the winter. “Those buds have become rabbit food,” Yiesla said.
The green, living parts of a woody plant are nutritious for an animal. In winter, most of the living tissue is found in the overwintering buds and in a green layer under the bark called the cambium. That’s why animals often chew the bark off plant stems, as well as eat twigs and younger branches.
“Losing branches to animals is less damaging to a plant than losing bark,” Yiesla said. “Plants can grow new branches in spring, but bark is harder to repair.”
If the bark of a stem has been chewed off all the way around, the stem can’t survive because the animal has severed the tissues that transport water and sugars between the roots and leaves. “When stems are girdled like that, it’s best to cut them back to the ground,” she said. “A healthy shrub will probably send up new stems from the roots.”
Shrubs are not out of the woods just because winter is over. “Animals are still hungry in spring, when plants open up all those succulent green leaves,” Yiesla said. “It’s a buffet for them.” Rabbits have very broad tastes if they are hungry enough, so there are no plants that are reliably rabbit-proof, she said.
The best way to protect vulnerable shrubs is to surround them with a physical barrier, such as a cylinder of chicken wire. Since rabbits can stand on their hind legs to reach tender twigs and succulent buds, the fencing needs to be at least 2 feet tall. “Taller is better, because rabbits can run and stand on top of snow,” Yiesla said. “In winters with very deep snowfall, even fencing won’t provide full protection.”
Some repellent sprays may help discourage animals, especially products containing capsaicin, the compound that gives hot peppers their heat. “It won’t hurt the rabbit, but it gives it a hot mouth and deters it from chewing very long,” she said. Sprays can be labor-intensive because they need to be re-applied often, especially after it rains.
Learn more about how to deter animals at mortonarb.org/animal-damage.
At a minimum, make notes now of shrubs that were damaged by animals over the winter so you can remember to install protection next fall.
“A shrub can generally recover from an occasional bad winter,” Yiesla said. “But it may not survive in the long term if it’s chewed year after year. And if rabbits ate a shrub this winter, you know that shrub is something rabbits like to eat.”
For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant-clinic, or plantclinic@mortonarb.org). Beth Botts is a staff writer at the Arboretum.
