MICE, VOLES AND LARGER CRITTERS

We all start out planting gardens, orchards etc. with much enthusiasm. We pick the spot, prepare the soil, plant our tree, tend it lovingly, watch it grow and bask in our success. Then the critters attack.

They come in all sizes from petite voles to giant moose. They inflict damage from slightly defacing all the way to certain mortality. People who live in the Edmonton area can attest to the horrible surprise we got in the spring of 1997 when, as the snow melted, the incredible damage done by meadow voles began to appear. These little critters had chewed the bark on trees and shrubs sometimes for two to three feet. Nanking cherries seemed particularly hard hit with every stem chewed right into the heartwood. It seemed that no species was completely spared and the damage was very wide spread. Some gardeners lost virtually every tree in their yards.

On the subject of larger critters, I’m constantly getting calls about deer, moose, porcupines and rabbits, not to mention the domestic pests such as goats, cattle and the family pets, cats and dogs. This all brings us to the question, what can we do to control these critters? Larger beasts, the deer, moose or the domesticated species can be difficult to control, simply because of their size and the extent of their reach. The damage they inflict can range from nibbling a few branches to eating the whole tree. The other form of damage is from rubbing.

The only permanent solution is fencing. A tall sturdy fence around the perimeter of your growing area can be very successful. Unfortunately this is a very expensive solution and can be unsightly as well. Short of perimeter fencing, each tree can be fenced, particularly young trees. This allows them to grow until they reach a height at which they can survive the pruning of their lower branches to the height that the critters can reach. Larger unfenced trees are still vulnerable to rubbing which can totally debark them. Wrapping the trunks with chicken wire or some other type of guard will help protect them. Remember to loosen the wire once in a while as the tree grows so that it doesn’t strangle the tree.

Many people try deterrents to keep the animals away. Soap, mothballs, human hair, blood meal, milk cartons containing blood hung in the trees as well as ribbons, silver paper or other moving objects hung in the trees. These methods may work for a while but the animals simply get used to them in the end and ignore them completely. Perhaps if you are prepared to change the type of deterrent the effect will last longer.

There are sprays that can be used on the trees. Most of these are thiram based and give the bark a bitter taste. It may be necessary to reapply these throughout the season to keep the taste strong. This can be inconvenient especially during the winter. These sprays can also be mixed with white latex paint and used as a sun scald preventative.

Having a dog around the yard is a great deterrent. Some commercial orchards fence the orchard with an electronic dog fence and simply keep a couple of dogs in the orchard to chase off the deer.

On to smaller creatures - some of the same deterrents can be used on mice and rabbits. They are sensitive to smells and if there is a choice will tend to eat untreated material rather than that which has been sprayed or has blood meal etc. spread around it. Some folks have had good success in spreading sewer sludge fertilizers around the bases of the trees. Again I think the success of these products is really dependent on the availability of alternate food sources and the animals not becoming too familiar with the smell or taste.

Setting up bait stations will provide an alternate and deadly source of food. Be sure that they are protected from other desirable creatures. We use plastic milk jugs with holes cut in them on the underside of the handle to allow the rodents to enter but to protect the bait from birds. If there are dogs around you may have to find a heavier container that the dogs won’t be tempted to chew.

Keeping tall grasses away from the base of your trees will create an undesirable area for the mice to feed. Dogs and/or cats around the yard will significantly lower the rodent population and the result will be less damage. The use of guards around the tree is very effective against mice and other chewing critters. Plastic spirals may be purchased at garden centers, pvc pipe can be used or even metal guards or screening. Be sure to bury the base of the guard in the soil and extend them well up the tree. They should be snug enough around the trunk so that the mice can't get between the guard and the trunk.

A simple solution for mice etc. is to tramp the snow down around the base of the tree as it falls in winter. The mice will not tunnel through hard packed snow. Porcupines like to strip the bark off the trees. They climb the trees to do this so if you can create some kind of guard for the base of the tree to stop them from climbing, it will lessen your damage.

Rabbits that nibble at branches can be a little more of a problem. Other than the deterrent sprays etc., some sort of guard is probably your only solution. Throwing coarse netting over valuable plants may be your only recourse. Dogs are also good deterrents for rabbits.

So, you've taken some precautions but you still have damage. What do you do? If you spot damage to trunks as the snow goes, get out there and paint it right away with a pruning paste or a latex sealant. This will help maintain moisture and if the chewing is restricted to the outer bark you may be able to save the tree or shrub. The same would apply to damage from rubbing. The trick is not to allow the area to dry out. My preference is to use the latex sealants, as they seem to provide a better seal than the black pruning pastes. These sealants could also be used for porcupine damage, although the damage they do is often more severe and is not repairable particularly if the bark is stripped completely around the trunk.

Depending on the extent of the damage it may be possible to repair it by bridge grafting or inarching. These are grafts that are placed in a way to reconnect the live material above and below the damaged area.

Critters of all sizes are a problem that we have to deal with in the environment in which we live. Don't loose heart, however, as there are deterrents and methods of damage control. There will be years that are better than others and the taste of those fresh picked fruits will soon help you forget the critters.

Amanda Chedzoy

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