Dear Master Gardener: Deer browsing has been terrible this winter. The deer have been eating plants I thought they avoided, like spruce and junipers. What can be done to protect plants from deer?
Answer: There have been many complaints this year (and last) about deer devouring landscape plants they haven't bothered in the past. Deer can cause severe damage to plants and when they are starving no plant is safe. A local master gardener was stunned when she discovered a deer eating the evergreen Christmas wreath on her front door! Although not attractive, the most effective method for protecting your trees and shrubs from deer browsing is to erect physical barriers to prevent them from getting to your plants.
For the past two years Kent Scheer, owner of Green Island Preserve in Wadena, with support from the University of Minnesota Extension, has been conducting research on micro-exclosures for keeping deer away from plants. A micro-exclosure is a small fenced area meant to exclude deer, based on the premise that deer avoid entering small spaces because they are afraid of getting trapped. In the trials, 16-foot-long cattle panels were used and connected at the corners with cable clamps to form a 16-foot square, leaving one corner unconnected to serve as a gate. Scheer used four 6-foot steel T-posts with one wired to the center of each panel to increase rigidity. The top wire across the exclosures measured 50 inches from the ground. During the two-year trials micro-exclosures have shown a high success rate with only one deer breach occurring. Once Scheer reduced the size of the micro-exclosure by cutting it in half, no further breaches occurred. For those who are trying to grow fruit trees and other food, this may be a simple, low-cost way to protect plants from deer. The details of the research can be found at https://extension.umn.edu/rsdp-happenings/protecting-our-gardens-deer.
Repellents are another option for deer control. During the summer months, commercial sprays can be effective, as well as homemade egg sprays, as long as they are applied diligently. Repellent sprays need to be reapplied every two weeks or after a heavy rain. Repellents work through a deer's sense of smell, so the solution is not effective over winter. In 1994, two University of Minnesota professors conducted a study comparing deer response to a variety of commercial repellents, methods of application and concentration levels. The study also included a homemade solution of eggs and water. Interestingly, they found the homemade solution of three chicken eggs blended thoroughly in a blender with 3.78 liters of water to be the most effective repellent. To apply the homemade mix, pour the egg mixture into a container and add water to reach one gallon, then strain it. Thoroughly spray the mixture onto new plant growth until the leaves are wet. In this same study it was found that adding other ingredients to the egg-water mixture, may mask the egg odor enough to reduce the repellent spray's effectiveness. Commercial products may protect longer, but this homemade concoction can be a great substitution if you run out of commercial spray or want to save money.
Dear Master Gardener: I have planted several Honeycrisp apple trees but they keep dying. My neighbor's Honeycrisp apple trees get apples. Because I have sandy soil, I put compost and rich dirt in the hole when I planted them. I also have other University of Minnesota apple trees for cross-pollination. Why can my neighbor get Honeycrisp apples and I am not having any luck?
Answer: Honeycrisp apple trees are not reliably hardy in our area. They are hardy to zone 4 and we live in zone 3b. There is about a 50 percent success rate in our county. Your neighbor may have a microclimate where his tree is located that you do not have. Microclimates are small areas that are warmer, or colder, than the surrounding locale. If the area where your trees are located is more shaded, it may be cooler because it is not getting as much sun. Additionally, if your neighbor's tree is more sheltered from the wind than yours, that affects temperature and humidity. Any or all of these factors can create a microclimate.
A tip when planting any tree-if you only put amended soil into the planting hole, the roots of the tree will want to stay in that rich environment and not spread out like they should. The hole should be at least 1-2 feet wider than the size of the root system, but only deep enough for the root flare (the first big root) to be planted at or slightly above the surface. A wide hole will allow for better root growth, especially in poor soil. Rough up and slope the sides of the hole so it is slightly wider at the top than the bottom.
April garden tips
• Make sure to check plants and seed packets for USDA hardiness rating if you are buying or planting perennials. We live in zone 3.
• Prune forsythia, Rhododendrons (azaleas), lilacs and other spring-flowering shrubs only after they are finished blooming.
• Those glossy ads for "miracle plants," such as zoysia grass, tree tomatoes, hardy peaches, etc. are a waste of money! Buy from reputable mail order sources and local nurseries or garden centers who guarantee their plants.
• Direct seed early vegetables, such as leaf lettuce, onions, radishes and peas into the garden as soon as the soil has dried enough to be workable. They can all take the cool soil and air temperatures. Sweet peas can also be seeded in cool soil.
• Pansies, violas and Johnny jump-ups can be planted late this month or early May. They tolerate light frost with no problem, but if they've been grown in a greenhouse you should gradually expose them to outdoor temperatures if you are planting them this month. Dead-heading flowers will promote more blooming.
• Keep foot traffic to a minimum on your lawn until it is no longer moist and spongy.
• Ads for crabgrass-prevention may start appearing this month, but it is too early to apply the products here. May is the time to use corn gluten meal or synthetic pre-emergent herbicides.
• Annabelle hydrangea may be cut back to the ground. It blooms on new wood and will quickly grow back and bloom in mid-summer.
• Lightly rake your lawn to remove dead grass, sticks and debris.
• Don't worry if your daffodils, tulips and other spring blooming bulbs get covered by a spring snowfall. As the snow melts, they usually re-orient themselves and will grow more upright again on their own. The snow is not cold enough to damage the plants.
University of Minnesota Extension master gardeners are trained and certified volunteers for the University of Minnesota Extension. All information given in this column is based on university research. To ask a question, call the Master Gardener Help Line at 218-454-GROW (4769) and leave a recorded message. A master gardener will return your call.