Neil Sperry

Neil Sperry: Think of trees as your landscape’s treasures

A retaining wall raises the grade but keeps a maturing tree’s roots at the original elevation.
A retaining wall raises the grade but keeps a maturing tree’s roots at the original elevation. Special to the Star-Telegram

Some of the things we do to our trees are outright criminal. Considering the fact that they are our most valuable landscaping investments, you’d think we’d pay better attention.

I recently spotted a crape myrtle tree that had suffered more than a few human-inflicted insults.

The poor tree had been staked, yet no one had ever bothered to remove the hose that was put in place to keep the wire from rubbing against the trunk — so the trunk has grown completely over the hose. Meanwhile, someone had gouged the trunk with a line trimmer.

At least they had finally quit topping it. Crape myrtles seem to get more than their share of the mistreatment.

Letting a tree seedling germinate and grow wherever it wants to akin to letting a 3-year-old decorate your house — usually not a good plan.

Site selection

Sometimes we plant the wrong tree for a given spot in our gardens. Or we let a tree seedling germinate and grow wherever it wants to.

By the way, that’s akin to letting a 3-year-old decorate your house — usually not a good plan.

You need to know how tall and wide a tree will grow before you assign a specific place to it.

If the tree isn’t a good match, don’t plant it. That’s how we end up with trees that have to be V-grooved, flat-topped or square-sided. Those power lines and city streets were there before we and our trees were, so the finger gets pointed at us.

Sun damage

Tree trunks can be damaged by exposure to sun. Just like our skin gets dry and cracks when it’s unprotected, so can the thin-barked trunks of red oaks, pistachios and others.

While the trees are in the nursery, they shade one another, but when we bring them home and plant them out in the open individually, suddenly they don’t have enough leaves to shade their trunks. It’s incumbent on us to apply paper tree wrap from the ground up to the lowest branches and to leave it in place for a couple of years.

Not only will it protect against sunscald, but it will also keep borers from invading the trunks.

After a few years, the tree will have produced enough bark to protect itself from the elements.

Beware the birds

Birds like woodpeckers and sapsuckers can sometimes do harm to our trees. Fortunately, it’s usually only cosmetic.

Their presence doesn’t imply that there are insects in the trunks, nor do the holes present any kind of pending doom to the trunk — unless the bird decides to camp out on one trunk and circle repeatedly. Eventually, that kind of repetitive drilling can do some harm.

A solution is to wrap the trunk with the same paper tree wrap, or apply a gooey old-fashioned product called Tree Tanglefoot to discourage them from clutching onto the trunk.

As hard as it is to imagine, you can kill a large tree faster by adding 3 inches of new soil than by taking away twice that amount.

Trouble with stubs

We leave stubs when we remove limbs from our trees. Branch stubs are never good things. Each cut should be made virtually flush with the remaining trunk or branch. Leave only enough of the “branch collar” that the wound can heal quickly, before decay sets in.

The cosmetics of root flares

Root flares are important factors that gardeners often overlook.

Trees’ roots almost always extend out horizontally just a few inches below the soil’s surface. As the tree grows larger and larger, the roots can swell up and out of the ground. Some people feel that all tree roots should be covered with soil, but that’s simply not the case.

You want to leave the root flares near, at or even above the soil surface.

‘Mulch volcanos’ and thirsty trees

When mulching your trees, don’t create what some refer to as “mulch volcanoes.”

Mounds of organic mulch and even soil will soak up moisture before it can get to the roots. Use excess soil that results from digging the tree’s hole to form a water-retention basin around the new tree. Plant at, or only slightly above, the level of the surrounding soil. Then add an inch of pine bark mulch on top of it all.

Carrying this one step further, you never want to spread soil across the entire root zone of a tree. Roots that had been near the soil surface will suddenly be covered by new soil that acts to drive out the oxygen.

As hard as it is to imagine, you can kill a large tree faster by adding 3 inches of new soil than by taking away twice that amount.

That’s why really good landscape architects and contractors take such pains to maintain those original grades, even when it entails construction of expensive retaining walls and tree wells. The results pay off big time.

Expert opinions

If you’re unsure of how best to care for your valuable trees, find a certified arborist. That’s a level of licensure that lets you know the person has training in, and knowledge of, the principles of outstanding tree care.

The DFW Metroplex is well supplied with skilled men and women in the tree-care industry.

Neil Sperry publishes Gardens magazine and hosts “Texas Gardening” from 8 to 10 a.m. Sundays on WBAP/820 AM. Reach him during those hours at 800-288-9227. Online: http://neilsperry.com.

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