Category: The Gardening Guy

Tree talk

Help yours survive and thrive

I’ll have to admit that I see many fewer volcanoes of mulch snuggling up to trees in public places. I think the word is out, at least with municipal workers, that trees can be damaged or killed by over-exuberant mulching. Among homeowners? I’m not so sure. Let’s take a look at the problem.
Tree bark is wonderful stuff: No matter the weather, bark protects its tree from rain, snow, cold or drought. But it is only rated for above-ground use. Bury tree bark, or cover it with mulch, and microorganisms will break it down and attack the green layer of cambium beneath the bark.
So what is this cambium layer? It is an active, growing layer of cells that produce the phloem and xylem tissue that provide for the transportation of necessary liquids and that provide mechanical strength. If the cambium layer is destroyed, the tree will die — but not right away. Most experts say that if the cambium layer is compromised, it can take six to 10 years for a tree to decline and die. First signs of the problem include tip dieback — top branches losing leaves — and earlier fall color than previously seen.
When you mulch around a tree, you should leave space between the tree trunk and mulch. Some say, leave a doughnut hole around the tree. How much? Four to six inches is good, depending on the size of the tree. Bigger tree, bigger space. And even if you have started with a mulch-free space around the tree, don’t assume there is still a space. Go look. Gravity works 24/7, and rain and wind can move mulch a little.
Don’t get me wrong: I am not against mulching around trees. It serves two important functions. It keeps down weeds, and it keeps away exuberant guys (usually) with weed whackers. No mulch? That guy with ear protection and a raging string trimmer can girdle your tree in a heartbeat. And that would be as bad as letting mulch slowly rot the bark.
By pulling away the bark mulch, you can save the tree. I have removed mulch and seen damaged bark. But if the cambium is still functioning, the tree can recover, and I’ve seen that, too.
There is another way that the cambium layer can be compromised: covering the trunk flare with soil at planting time. Burying the portion of the tree that should be above ground will lead to a slow death.
Growing trees is an industry. Americans buy hundreds of thousands every year. They are sold at local family-run nurseries and big box stores, but they’re often started in nurseries in the warmer regions of the United States. Trees are often grown in fields, like corn, and then lifted and potted up to be sold to your local nursery.
If you ask how deep to plant your little tree, the most likely answer (from my informal survey of homeowners) is “Plant it just like it is in the pot.” But that is generally bad advice. The process of taking a field-grown tree and getting it into a plastic pot is not precise. Time is money, so trees are often plunked in containers with little regard for the depth they were growing in the field. The trunk flare (that part that should be above ground) is often buried.
To recognize the trunk flare of a tree, go outside and look at a tree planted by Mother Nature. You will see at the base of a tree that there are above-ground roots heading away from the tree, and that the base of the tree widens just above ground level. That wider portion is the trunk flare and must be above ground.
Before planting a tree, take your fingers and pull away the soil from the tree trunk at the surface until you can see the trunk flare. If the tree has been in the pot for a few years (often the case for larger trees) and the flare has been covered, little roots have started to grow out of the trunk flare and should be cut off.
Larger trees for sale at nurseries have often been moved from their original pots or bags to larger ones. At that juncture, soil is added, and it often covers the trunk flare. I have planted trees that came from the nursery with four to six inches of soil over the trunk flare. By removing that, I saved the trees.
What should you do if you planted a tree without regard to trunk flare? Take a look at it carefully. If your tree trunk is as straight as a telephone pole at the soil surface, you need to do some digging. You need to expose the trunk flare.
I like to use a single-tine hand tool called the CobraHead weeder (CobraHead.cm) to expose the trunk flare. I gently and slowly loosen soil and pull it back with my hands. In fact, I use my fingers as much as possible, as I don’t want to damage the bark on the trunk flare. Once you see the flare, re-grade the soil around the tree trunk. It is not as scary a proposition as it sounds.
Trees are our friends. You have to be sure they are properly planted and tended, so go look at yours. You may have to do some work on the next warm day.

Featured Photo: Don’t create mulch volcanoes like this. Courtesy photo.

Dealing with deer

Fences, repellent and other deer deterrents

Winter is near, and for most of us so are the deer. They need extra food now, to get ready for winter, and some of what they eat — green leaves and grasses — is not readily available. So they are eating evergreen plants like yew, arborvitae and rhododendrons in our yards. There are steps you can take to help save your shrubs.

What can you do? You’ve probably heard the solution, but might not like it: an eight-foot deer fence around the perimeter of your property. Even then you might get an occasional Olympic deer that can sail over it. But generally deer are kept out by such a fence.

You don’t have to have a steel fence — lightweight plastic fencing will work, too. And you can use poles to support the fencing, straight young tree trunks you cut yourself from the back forty. And you don’t have to fence your entire property. You could put up temporary fencing just for the winter around a tree or shrub that is particularly attractive to deer that has been browsed in the past.

Recently I helped set up barriers around a pair of large yew shrubs. The shrubs are about six feet tall and wide, and in the past they have been stripped bare by deer. I got four eight-foot hardwood stakes and drove them into the ground around each shrub. I needed a stepladder and a three-pound sledge to do it.

The widest burlap we could buy was 44 inches wide, so my wife Cindy sewed two strips together to make an extra-wide band. We draped the cloth over the stakes, and stapled the cloth to the stakes all the way to the ground. We did not cover the top of the shrub, just the sides, so snow will fall through and not weigh down the cloth. It worked well last year — the poor deer went hungry.

What else? There are numerous repellents that work to a greater or lesser degree. I’ve had great luck using little garlic clips that I get from Gardener’s Supply Co. Each has a clothespin type clip to attach it to a shrub, and has a little cylinder filled with garlic oil. When you poke the device with a tool they provide, it releases the odors for up to six months. I use two per shrub, or more for bigger things or more attractive deer food.

Coyote urine is sold as a deer repellent, too. It is sold with one-ounce plastic bottles that have holes in the sides, a hanger on top and a cotton ball in the bottom. Dribble a little of their magic potion on the cotton, and hang it in a tree. Of course, you can also just bring your dog around the property and let him mark trees and shrubs. Some people hang bars of Irish Spring soap to discourage deer.

There are numerous sprays, too. Bobbex, Deer Away, Liquid Fence and Plantskydd are some of the most commonly sold varieties. Most use rotten eggs, garlic, or fish oils. You might not want to spray your plants the day of a garden party, but most odors disappear to us after a few days. If deer pressure is high, you might want to alternate which one you use.

Deer are creatures of habit. If they know you have good browse, they will come. If they think you have a pet coyote, they will stay away. No dog? Get dog hair from your local pet groomer. Some people hang sachets containing human hair or bars of Irish Spring soap out in their yard to repel the deer.

There are ways to scare deer away, too, but most take some effort to set up. You could install a motion detector attached to a radio with an all-talk radio format. When the deer arrive, Rush Limbaugh comes on and scares them away, I suppose. I’ve seen motion detectors that attach to a hose and send out spray when deer are detected. That only works in summer, obviously.

In areas of high deer population, gardeners sometimes choose their plants based on their appeal to deer. People, Places and Plants magazine (now, sadly, out of business) asked its readers to rate plants eaten by deer. They published the results in Issue No. 45 (2004). Here is some of what they said: Seldom eaten shrubs include boxwood, dogwoods, forsythia and spirea. Occasionally eaten shrubs include blueberry, hydrangeas, lilacs, summersweet clethra and viburnums.

Trees rarely pruned by deer include birch and ginkgo. Their survey listed occasionally eaten trees as Japanese maple, pear, pine, magnolia, spruce, willow and crabapple. I raised an eyebrow when I saw crabapple, as I frequently see apple trees that have been browsed by deer. Crabapples, I assume, would be the same, but please let me know if I’m wrong.

In areas with lots of deer, it makes sense to plant perennials that deer love near the house, and those eschewed by deer farther away. So hostas and tulips, loved by deer, should be right near the house. The survey found flowers usually eaten include lilies, daylilies, hollyhocks, black-eyed Susans, and asters. Scented things like lavender, artemisia and oregano are generally of little interest, and those seldom nibbled include balloon flower, bleeding heart, astilbe, foxgloves, columbine, peonies, Russian sage, yarrow and monkshood.

For a more complete list of deer preferences, you may want to consult a book on the issue. One I like is Outwitting Deer by Bill Adler Jr. But remember, if you have a plant that is dear to you, put a fence around it — there is almost nothing a hungry deer won’t eat.

Featured Photo: Burlap can be used to keep deer away from tasty shrubs. Courtesy photo.

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