Managing wildlife pests in the garden and landscape is a challenge for all gardeners. It’s not just those of us in rural areas who deal with damage from deer, rabbits, raccoons, moles, and other furry foragers. These creatures have a solid foothold in metropolitan areas as well. So, what to do to protect your garden?
This week, I spoke with Marne Titchenell, Wildlife Program Specialist at the Ohio State University Extension School of Environment and Natural Resources. Marne shared her advice on which deterrents work and which are just wishful thinking, all based on the latest research.
Deer Management for the Home Gardener
There are so many options for preventing deer from damaging your plants, trees and shrubs. Gardeners use repellents, scare tactics, barriers, and all kinds of creative methods to keep deer at bay. What really works? Well, that depends on a number of variables.
Deer have learned to coexist with us in our urban environment, and while deer population is controlled through hunting in less populated areas, there is little to control their advancement when they are entrenched in our neighborhoods. There simply aren’t many threats to keep their numbers in check.
As populations rise, deer become less selective with their appetites. So, you’ll need to remain vigilant and probably employ a few different methods during different times of the year or as deer populations rise in your area. Another thing to bear in mind, the longer a deer has access to a particular food source, the more difficult it will be to get them to leave that food source alone.
Let’s start with plant selection. Deer are known to eat up to 500 different plant species. They are less attracted to some plants than others, so selecting deer-resistant plants is a good start. Just remember that’s no guarantee you won’t see damage.
If a deer is hungry enough, it will eat deer-resistant plants too, and their feeding preferences change throughout the year. For example, they love mowing down the fresh spring shoots of my oakleaf hydrangeas, but as the season wears on and the surviving hydrangea foliage matures and toughens, the deer seek out more desirable options.
Repellents can be a good option if your landscape is receiving some but not heavy deer damage. Diligence is key when relying on repellents. This management approach is only truly effective when applied regularly and to all new growth. Whenever possible, apply before or immediately after you see damage to plants at risk. Be prepared to reapply every time it rains too. Since continual repellent application can be time-consuming, repellent will be most successful if you use it on an area that is small enough to realistically manage.
Repellents can be expensive, so if you’re using them on a large area, they may not be the cost-effective approach. Fence construction can be costly, but there may be long-term cost savings when compared to restocking your repellent supply season after season.
So which deer repellents work? Research has shown that, while that odor repellents tend not to work, taste repellents can be very effective. Any repellent with egg solids, blood, hot pepper, or capsaicin as an ingredient is your best choice. Some repellents contain both eggs and hot pepper or capsaicin, and those work particularly well.
Never underestimate how persistent and adaptive deer are. If they are hungry enough, they will acclimate to the taste of the repellent, so it’s a good idea to alternate different repellents to keep the deer on their “toes.”
Do you use scare tactics to keep deer at bay? Research has shown that, in general, that approach isn’t effective because deer are so adaptive. Anything which will surprise the deer – like motion-activated sounds, lights or water – can keep them away for a time, but you will need to keep moving the source. It doesn’t take long for deer to get wise to the mechanics and go back to browsing on your prize shrubs.
Deer won’t be deterred by any stationary object, like fishing line or spinning pie plates, for more than a day or two. These items can work for birds but not for larger animals. Deer will quickly learn how to navigate around or ignore these deterrents.
Many gardeners use human hair or soap to keep deer away. Research has found these not to be worthwhile strategies. That said, Marne recognizes that these may work for some gardeners. Once again, a lot depends on how pressured your local deer population is to find food and what other options they have available to them. If they aren’t under pressure, these milder deterrents may work.
If you’re experiencing heavy deer damage in your garden, that is a good sign the deer population is under stress, with food options in short supply. Those hungry deer will eat whatever they can get to. In this situation, a fence may be your only option.
Deer are expert jumpers, so in general, it will take a fence that is 8’ or higher to keep them out of your property’s perimeter. If you are fencing in a small area, you may be able to get away with a fence just 5-6’ tall.
Deer have terrible depth perception. Small, confined spaces make them nervous.
For example, the split-rail fence around my GardenFarm™ is just 4’ high. I wasn’t sure if that would work long-term. Fortunately, the deer don’t quite know how to navigate the densely-placed raised beds and tight spaces within my fence. So, they move on to easier pickings.
Marne is a big proponent of what she calls the “peanut butter fence.” A single strand or two of electrical fencing along a shorter fence line can become a very effective behavioral barrier. Fold pieces of tin foil or window screen material with a dab of peanut butter at various spots along the electrical strand. The deer will sniff or lick the peanut butter and will receive a shock to their tongue or nose. Since these areas are particularly sensitive, the deer will avoid future contact with the fence. The same electrical shock to any other part of their body will be negligible to the deer, so using the peanut butter approach is an important aspect of success.
It’s not just the foraging that can cause damage in your landscape. During fall rut, your trees are at risk of damage from bucks rubbing their antlers on tree trunks. Male deer rub to remove their summer velvet, or they may be leaving their scent for does and other bucks to mark territory. Either way, this damage can harm tree health.
A tree shelter – essentially a protective cover around the tree trunk – can protect your tree from rubbing. Select one of the sturdier, stronger tree shelters which will stand on its own and stake it to the ground far enough away from the tree to allow air flow and prevent direct contact.
Another, inexpensive option is corrugated irrigation pipe, available at most home improvement stores. You can slice the corrugated pipe lengthwise and wrap it around the tree trunk. This material is durable and allows enough space and oxygen to the tree but discourages bucks from rubbing.
All in all, successfully managing deer invasion and damage in your landscape is a moving target. These are some great options, but resign yourself to the knowledge that there is no silver bullet. Stay vigilant and don’t be afraid to get creative.
Protecting Against Rabbits
Like deer, rabbits are herbivores. They have sharp top and bottom incisors which cut plants at a clean 45 degree angle. So if you see clean bites on your plants, you know you have a rabbit problem. Roughly torn foliage is a sure sign of deer damage, since deer tear off instead of cut off.
The same management methods used for deer are effective on rabbits – taste repellents and fencing. Fencing is the most effective tool in smaller gardens and should be approximately 2-3’ high. Chicken wire staked into the ground can create an effective fencing barrier against these long-eared foragers.
Managing Moles in the Landscape
Moles are underground-dwelling insectivores. They feed under the surface on grubs, worms, beetles, and other invertebrates. They move through the soil surface by digging tunnels – also known as runways, which are often visible from the surface. There are primary runways (Marne compares these to highways) and feeding runways (Marne compares them to side streets).
The primary runways are the paths moles travel most frequently, so they tend to be straight and long. Feeding runways tend to be short and curved.
Why does this matter? It’s the long, straight primary runways that are your best spot for mole management. Since sound-emitting devices and repellents, like castor oil, have been shown not to be effective against moles – the best method for management is trapping. Most mole traps are kill traps, and there are many styles to choose from. Which style you use won’t matter, success is all about proper placement.
Traps are only effective when properly placed. Fortunately, there are plenty of videos on YouTube to show you the proper way to do this – just be sure to look for those created by wildlife control professionals. Always look for credible experts and sources when getting information online.
To identify a good trap location, Marne suggests pressing your foot down on a spot of one of the primary runways and mark the area with a flag. If the spot is raised back up a few hours later or the next day, that’s an indication the runway is being actively used.
Toxic baits can work, although granular and pellet form baits are not particularly effective. Like a trap, the bait should also be placed in an active runway, however unlike a trap, you won’t know whether or not the bait has done its intended job.
Another big downside to the use of toxic baits is, well, that they are toxic. The bait puts other animals at risk of poisoning too. A neighborhood pet may find the bait before the mole does, or a pet or another predator may dig up and eat the poisoned mole and be poisoned too.
Placing toxic chemicals in and around your property can always create unfortunate unintended consequences. I strongly recommend against using toxic baits for management of any pest. The unintended consequences just aren’t worth it.
Vole Management in the Garden
Voles are rodents which live above the surface and eat only vegetation (V for voles and vegetation). You’ll know you are experiencing vole damage when you see chewing at the base of your plant, or if the plant feels loose in the soil, it’s because much of the root system has been eaten away.
Voles feed on various plant parts like roots, tubers and seeds; and their damage is typically focused near or just beneath the soil surface. They create surface tunnels in thick mulch, thatched grass, etc. So one of the best vole management options is to modify their environment.
If you have wood or other cover laying on the ground, remove it. Pull mulch back away from from direct contact with the base of your plants. Avoid using tall landscape grasses if voles are a particular problem in your area.
Voles don’t like to be exposed to the peering eyes of predators, so if you remove their cover, they will be less inclined to risk being vulnerable to snack on your plants.
Traps work well for managing voles too. Snap or mouse traps are the best option and should be placed in the pathway along the vole tunnels and near any plant damage you’ve observed. Voles sometimes dig shallow holes to get at plant parts, and these are good locations for traps as well.
It’s important to cover the traps, so that other animals don’t fall victim. Fold a large piece of cardboard or place a large pot over the area. Because the trap is in the direct line of a food source, adding bait isn’t necessary, but if you would like to create more enticement, apple slices and oatmeal mixed with peanut butter are good options.
Using a repellent, like hot pepper, can curb vole damage. Taste repellents are the most effective option for voles and should be applied around the base of the plant. Unfortunately, voles are prolific breeders, so when their numbers are surging, repellent may not be as effective. It can be worthwhile to add some sort of barrier, like a wire cage around your plants and roots as added protection.
Toxic baits are available for vole management, but these carry the same risks as all toxic baits.
Not comfortable killing moles or voles on your property? I feel the same way. Personally, I don’t do anything about these creatures on my property. Yes, moles can do damage to turf when their digging dislodges grass roots from the soil, but that is an aesthetic issue which is easy enough to remedy. Vole damage can be frustrating too.
Yet, I would rather co-exist with their damage than kill them with a trap or poison. Every gardener needs to choose his or her own threshold of tolerance.
Managing the Climbing Critters
When you are doing battle with raccoons, groundhogs, squirrels, and other agile climbing pests; you have your work cut out for you. Their nimbleness allows them to scale nearly any fence, so a barrier isn’t really an option.
Take a look around your landscape. Consider what might be attracting these pests and make adjustments when possible.
If you have fruit trees, be diligent about picking up fruit that falls to the ground. Don’t put out your garbage until early morning, so it’s not a temptation for nocturnal pests. Keep pet food inside if at all possible.
Some of these types of pests, like skunks and raccoons, are carnivores and attracted to areas with lots of prey. So if you have a barn or other area with lots of rodents, you may be able to eliminate the larger pests by managing the rodent population. Raccoons and skunks also like areas which provide cover, so you can make your yard less attractive to them by preventing access to these nooks – like under your patio.
Research has shown that repellents don’t work against these types of pests, so if modifying your environment doesn’t work, trapping may be your only option.
Traps for the smaller pests tend to be kill traps, but what about live trapping pests? That may be an option in your area, but there are rules and regulations on the issue. Check with your state’s wildlife agency to learn which pests you are allowed to trap and release elsewhere. Relocation is restricted in many areas due, in part, to prevent the spread of disease among animal populations.
Relocation isn’t always the humane option either. Some animals, like rabbits, simply don’t adjust well to a new environment. Since they can’t adapt quickly to a new home, they will often die in their new territory.
As a final thought, I would ask that you reconsider the term “pest problem.” Do you actually have a pest problem, or are you experiencing a little damage which you can opt to live with. This is a question each gardener must decide for his or herself. We must each take a look at the bigger picture in our landscape and decide if this a situation requiring management efforts or a little more patience and willingness to share.
If management does become necessary for you, do your homework and be mindful of the risks involved.
You can listen to the podcast recording by scrolling to the top of the page and pressing the play icon in the green podcast bar under the title. In the recording, you’ll hear Marne describe trap placement details as well as other pest management examples.
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