deer – The Garden Professors™

You and me Baby ain’t nuthin’ but mammals…

As spring slowly makes it appearance in the Midwest, homeowners and landscapers are likely to continue discovering damage from our record-breaking winter. While brutally cold temperatures and heavy snow loads took their toll in many areas, some of the most severe damage that occurred to landscape trees and shrubs this winter was caused by mammals.

Our long, harsh winter resulted in heavy feeding damage by deer, rabbits and voles, also called field mice. Depending on the age and type of plant and which animal was feeding on it, mammal damage can range from light pruning to death of a tree or shrub. Developing a strategy to deal with animal damage requires proper identification of the offender. Here are clues to identifying mammal damage.

Vole damage
Voles or field mice are small rodents that gnaw on tree and shrub stems. Voles do not hibernate and are active throughout the winter under snow, so feeding damage that occurred near ground-line when the ground was covered with snow is likely vole damage. Although they are small, voles can wreak a lot of havoc. They can easily kill small trees or branches on larger trees by girdling stems, or removing the bark around the entire circumference.

Voles (or field mice) can completely girdle trees.

Deer damage
During the winter, deer feed on the ends of many types of trees and shrubs. Evergreens, especially arborvitae, are among their favorites. In most landscapes in this area, a “browse line” is a common feature on arborvitae. Eastern white pine, maples, birch, dogwoods and viburnums are also favored trees deer browse. This winter, I received reports of deer browsing on secondary species, such as Austrian pine, reflecting the severity of the winter.

Rabbit damage
Rabbits can cause damage that may resemble feeding by either voles or deer. Like deer, rabbits will chew the ends off of deciduous trees and shrubs. A close inspection of the end point will often indicate the culprit: rabbits typically leave a clean, angled bite mark, whereas deer tear or break stems, leaving a rough edge. Like voles, rabbits can also girdle stems of trees and shrubs. In winters with heavy snow cover like this one, the height of the damage can provide a clue; vole damage will extend down to the soil surface, while rabbits work above the snow-line.

Clean, angled bite-marks: A telltale sigh of rabbit activity.

Managing mammal damage
Managing mammal damage is often difficult and multiple strategies may be needed. Excluding deer with fencing can be highly effective, but is not practical in many instances. Deer repellents can also be effective, but may wear off over time or become less effective as deer become hungrier as winter wears on. Around our place, our dogs to a good job of keeping deer and rabbits at bay, but of course require their own care and feeding.
Reducing weeds and ground cover can help to reduce damage by rodents by eliminating cover from their predators. Trapping may be effective for controlling rabbits, but is usually not practical for voles. Baiting can be used for voles, though care must be taken to avoid poisoning non-target animals. In some situations, erecting raptor perches can also be helpful in keeping rodent populations down.

Tomatoes, Dingleberry Deer, and the Goose Poop

Do you ever get annoyed right after you eat a nice, ripe, homegrown tomato at those little pieces of tomato skin that get caught in your teeth, or even against the roof of your mouth? Sure, the tomatoes are worth it, but those little pieces of skin can drive me up the wall for hours afterwards, especially after eating a bunch of cherry tomatoes.

This post is about how I learned to get rid of those little tomato bits.

It all started a few weeks ago when I posted about a new type of bag that you could put on your fruit to protect them from insects, animals, or whatever. You can see that post here.

Anyway, since that time the deer have come again and again to my garden, and they have targeted all of my almost but not quite ripe tomatoes. Unless you’ve experienced it, it’s impossible to imagine the frustration of going out one evening and seeing a bunch of tomatoes just starting to change color, and then the next morning going out to see them again – and they’re all gone.

Fortunately for me, the tomatoes that I put bags around were saved from deer.

The tomatoes above were protected by bags — overall they worked well

The funny thing was, about a quarter of the bags that I used for bagging those tomatoes went missing. I figured that was no big deal though. The tomatoes probably just aborted for some reason, the bags fell, and the wind blew them into the neighbor’s yard – not my problem anymore!

And then I saw this huge piece of goose poop out on the lawn not too far from the garden. Now don’t get me wrong, goose poop is no big deal – usually I don’t notice it at all– but this was such a big pile that I couldn’t avert my eyes. After a week or so of having this pile of poop sitting in my yard I had had enough. Even though it had rained, this pile just wasn’t disappearing.

So I went over to investigate.

Goose poop, or the leavings of an evil deer?

As you may have already guessed, it was a bag that I had protected one of those tomatoes with. I could tell from the red flecks inside that it had held a beautiful red tomato. Some dingleberry deer plucked that bagged tomato off the plant and sucked out the yummy guts of the tomato while leaving the nasty skin behind.

And that’s how I learned to get rid of the skin from my tomatoes.

Who you gonna call?

As I noted last week, this has been a long winter in Michigan – OK, Jeff, no chortling from the frozen tundra of Minnesota… Most gardeners in this area have only been able to do their spring yard and garden clean-ups in fits and starts as the weather allows. We’re finally warming up a bit this week but now strong storms are in the forecast. One of the things gardeners will want to do is to size up any winter damage that has occurred since they put things to bed last fall. Although our winter was long, it was otherwise unremarkable with few temperature extremes – low or high – that would likely cause problems. In fact, aside from some heavy snow in February, the winter of 2010-11 was probably the closest thing we’ve had to a ‘normal’ winter in the 11 years I’ve lived in Michigan. Nevertheless, we will still be taking numerous extension calls on what we would consider ‘typical’ winter damage to trees and shrubs.

In this neighborhood not too far from my house, deer have declared open season on arborvitae.

One of the biggest issues we face is wildlife damage. The two biggest sources of problems are small mammals and deer. Small mammals such as mice, rabbits, squirrels and voles cause damage mainly by gnawing on trunks and branches. Despite their small size, these animals can kill trees by removing bark and underlying tissue around the circumference of a tree trunk, a process referred to as ‘girdling’. If a large portion of trunk circumference has been girdled, trees are unable to move energy reserves between roots and shoots, and will eventually die. Deer can cause extensive damage to trees and shrubs due to feeding and also through rubbing their antlers. Deer feeding is often indicated by a ‘browse line’ based on how high deer can reach. Rub damage from deer antlers can cause major deformation to trunks and can even kill trees by girdling. I was in a new subdivision in the East Lansing area this weekend and well over half of the trees on the tree lawns will need to be replaced due to extensive deer rub damage.

At least half of the trees in this entire subdivision will need to be replaced due to deer-rub damage.

Dealing with wildlife damage is a complex issue and varies with local conditions and wildlife pressure. Fortunately, wildlife experts from several universities (Cornell, Clemson, Nebraska, Utah State) have organized the Internet Center for Wildlife Damage Management. http://icwdm.org/ This site is one of the best resources I have run across for assessing and dealing with wildlife damage issues. If you’re in a position where you have to deal with wildlife damage or advise clients about damage, this is a useful site to add to your bookmarks.

Deer Finale (and then we move on…maybe)

I believe I may have shared this with you previously…pardon the recycling.

But cogent to the discussion (and still breathtaking in its absurdity…)

About $1000 worth of 10′ tall Arborvitae that were freshly dug, moved to a commercial job site, and then EATEN ALIVE before they were even planted. The remains (seen here) were shipped back to the wholesaler near Richmond. My guess is that deer evolution may be headed in the direction of longer necks. In another epoch they’ll be…giraffes. Minus the festive coat pattern.

Oh Deer! Part 2

Last week Holly and I extolled the virtues of our dogs for helping to keep our gardens and landscapes relatively deer-free even though we live in areas with high deer pressure. Of course, letting dogs roam your property is not an option for everyone. So what are some other options to keep deer from turning your garden into a salad buffet?

My former grad student, Sara Tanis, shows off deer damage at her parent’s place near Ludington, MI

One of the most popular non-canine deer remedies is applying various deer repellants. Typically I’ve been pretty skeptical of deer repellants. Trying to stop hungry deer from chowing down on your garden is like trying to stop a high school football team from devouring an all-you-can-eat pizza buffet. Recently, however, I saw some results from some colleagues at North Carolina State University on the effectiveness of various deer repellents in Christmas tree plantations that looked promising. Deer damage is a major issue in Christmas trees; deer browse pressure can be very high on conifers since they may be the most palatable thing available to deer in the winter. Research at NCSU and other studies (Wagner and Nolte 2001, Wildlife Soc. Bull.29:322-330) indicate that repellants that contain putrescent egg solids or animal protein can be effective at reducing deer damage. Of course, no repellant is 100% effective. If they’re hungry enough and don’t have an alternative, deer will likely overcome their fear of these scents and still come in for a nibble. Also repellants need to be re-applied periodically to be effective. Nevertheless, for gardener’s at their wit’s end and ready to resort to high velocity lead, repellants may be a better alternative. Although Sara says lead works too!

The Deer Thing

Gave a talk last week to the Arlington, Virginia Master Gardeners and friends (howdy!). What a wonderful group. I was warmly welcomed, they brought awesome goodies, and even laughed at my silly anecdotes.

As is inevitable during any plant presentation, the topic of deer came up. When the question arose of whether a particular perennial that I had enjoyed in my own garden was deer-resistant or not, I responded with “I’m not sure, I don’t have a deer problem.” I regretted my words the moment they came out. The audience erupted, and I swear cupcakes were (figuratively) flung at my head.

1. It was incredibly insensitive of me.

But I didn’t know! I was gently informed that yes, deer were indeed a huge problem. Arlington is tucked deep within the Beltway, right next to D.C. Though they have some nice green spaces and lots of big trees, I wouldn’t describe it as suburban, which is where I’ve heard all the deer problems were in Northern Virginia. The D.C. metroplex is bumper-to-bumper traffic about 22 hours per day, at least in the experience of this Country Mouse. How they haven’t been wiped out by deer-vehicle collisions, I’m not sure. Maybe the traffic never goes fast enough. I feel just awful for these folks. One lady described afterward how she couldn’t even have pansies in a container on her patio. She said she gardens “in her dreams.” I misted up.

2. I then had to try to explain why I don’t have a deer problem.

I’m not sure! What’s worse, I haven’t had too much of a problem at any of my previous residences (just digging the hole deeper, aren’t I). Currently, we live in the Country with a capital “C”, on the side of a mountain, surrounded by forests, pastures, streams, etc. There’s minimal fencing. The nearest neighbors* are not very near. We should be crawling with deer.

Don’t get me wrong, there are plenty around – picturesque herds roam the hayfields across the valley. Driving home at dusk in the spring and fall is an adventure in deer-dodging. They do occasional visit closer to the house, traipsing through our blueberries, and eating fallen apples, or nibbling the tops out of my okra. They have damaged some of our veg garden, but no worse than our own destruct-o-chickens. But they rarely mess with the ornamentals. Of which there are LOTS.

* Incidentally, most of those (very nice) neighbors possesses multiple rifles and armloads of 30-06 rounds. I know this because deer season is nigh, and everyone’s adjusting their scopes and blowing out the dust. Blam, blam, blam.

My best guess as to our relative freedom from deer damage? Neighbors who enjoy deer steaks, plus an active assault-hound program. OUR weapons of choice:

Bebe (B.B.) the Basenji-mix and Bunny the Whippet. Faster than speeding bullets. Joel is asleep so I graciously cropped him out.

Not very fearsome as depicted here, but two sight-hounds can give the deer a run for their money. They love to patrol the grounds. Plus it’s great exercise for the little couch lizards.

The deer explosion has turned many people off from gardening (both novice and experienced). To have something you’ve grown and/or spent a chunk of money on – there one evening and gone the next morning – must be very, very frustrating. My heart goes out to the kind and hardy gardeners of Arlington and all others for whom deer are an absolute plague.

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Oh, Deer…

More from our Ornamental Plant Production class tour across the state. One of our stops was James River Nurseries, Inc. Owner Mike Hildebrand has a built a unique and diverse business – they not only grow but do landscape design-build-install, all in the huge market of central and northern Virginia and beyond.

Here’s some arborvitae that spent the past few weeks at one of their job sites north of Richmond, waiting to be planting. They’re now back at the nursery. I was going to make this a quiz, but it’s unfortunately just too obvious.

deer nibbles

Wow. Poor things never even made it into the ground.

Soap and Deer

Short post today — Linda appears to have transmitted her illness electronically over a couple of thousand miles — Thanks Linda!

I was reminded yesterday that it’s almost time for gardeners to start worrying about winter deer damage. With that in mind I thought I’d share with you my favorite research article on the subject. It’s a little paper by Michael Fargione and Michael Richmond and published about 18 years ago. You can find it here.

This paper attempts to establish how repellent bars of soap are to deer and comes up with some very interesting conclusions. The first thing you should know is that no one type of soap appears to be better than another. The second thing you should know is that soap does appear to stop deer from feeding around the soap — but the best you can hope for is a radius of protection of about a meter from the bar of soap itself — Can you imagine what that would look like if you were trying to protect the lower limbs of a large tree? And finally, bar soap appears to attract voles. Based on my reading, and my limited experience, I’ve found that almost everything that people say repels deer does repel deer — human hair, peeing around a tree, predator urine, dried blood — the issue is how long these repellents stay effective and how effective they are when the deer get really hungry. The most effective commercial deer repellents tend to have “putrescent egg solids” in then (rotten eggs) — I once had a graduate student who needed to protect some hazelnuts from deer and she found that a mixture of a few eggs (2-4) mixed in a quart of water and sprayed onto the trees worked pretty well — and no, the eggs weren’t rotten. This mixture should be sprayed about once every two weeks if possible.