Rabbit injury, sweet potatoes for northern regions, mugo pine winter burn
"Fielding Questions" columnist Don Kinzler recommends chicken wire or hardware cloth fencing to deter rabbits. He writes that repellents tend to be hit-and-miss, working for some people in some situations, but not others.
Q: What do I need to do to save the arborvitae in the photo, or is it toast? Is there something I can do to keep rabbits away during the winter? – Jay D.
A: Leafy, deciduous shrubs can recover from rabbit injury simply by pruning back the branches to a point below the injury, and they’ll usually rejuvenate fine. Evergreen shrubs, such as arborvitae, don’t have the ability to recover from rabbit or deer injury the way deciduous shrubs do.
If evergreen branches are gnawed and the foliage is stripped back to older inner bare branches, new foliage rarely regenerates in that area. That’s why past rabbit or deer injury is often evident for the remainder of an arborvitae’s life, and unfortunately there’s little remedy once the damage is done.
Chicken wire or hardware cloth fencing are the surest ways of deterring rabbits. Repellents tend to be hit-and-miss, working for some people in some situations, but not others. Of the repellents on the market, those with the widest rate of success include Liquid Fence, Plantskydd and Repellex. Home remedies such as mothballs, pepper and soap haven’t enjoyed the same success.
Q: Is it possible to grow sweet potatoes in North Dakota? I know they are grown down South, but are there any kinds we can grow up here? – Beth N.
A: Although sweet potatoes generally require a very long growing season, there are several varieties that produce tubers in a shorter time span. Types being grown successfully by gardeners in North Dakota include Beauregard, Covington, and Georgia Jet.
Sweet potatoes are grown from vine cuttings, called “slips.” Sweet potato plants can be purchased from some garden centers or ordered online. As a side note, garden centers also commonly sell ornamental types of sweet potato vines that do produce edible tubers, but they were selected for beautiful foliage and not for high-quality tubers.
Sweet potato plants or slips are planted in May after the soil has warmed. They won’t tolerate temperatures close to freezing.
Sweet potatoes will grow more rapidly if clear plastic is used over the soil as a mulch. Clear plastic laid directly on the soil admits the sunshine, creating a greenhouse effect over the soil and trapping the warmth. Roll out the plastic in a three-feet-wide row, weight down the edges with soil, make slits every 18 inches, and install the sweet potato plants.
Q: The needles on my mugo pine turned rusty brown this winter. The part that was below the snow looks nice and green. Will the burnt area recover, or is it dead? Should those branches be pruned down? – Tom P.
A: I’m seeing a fair amount of winter burn on evergreens, especially pine, which are the evergreens with longer needles. Winter burn can happen when sunshine reflected from the snow burns needles, similar to a skier getting a winter sunburn. It can also happen from strong winter winds, which seemed unusually common this winter.
To check whether the affected branches are alive, examine the buds at the branch tips. If they are sticky and appear plump and fresh, new growth will likely sprout from the buds. But if the buds are dry and brittle, growth is unlikely. Also look for plump, live buds along the secondary branches.
Waiting is usually the best advice for winter-damaged evergreens. By mid-to-late May you’ll be better able to assess damage. Winter damage to mugo pine can sometimes be pruned out with the remaining shrub recovering, if the damage doesn’t extend all the way back to bare branches.
If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at firstname.lastname@example.org. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.