Tree Care After a Terrible Summer

Published March 19, 2012, in the The Weekend Gardener / NEIL SPERRY / Fort Worth Star Telegram

When the guy's ringtone is of a chain saw revving, he might be an arborist.

I had a chance to visit with Steve Houser, owner of Arborilogical Services, a few days ago as his crew worked 50 feet up in our trees. Steve is highly respected by his crews, his clients and even his competitors. He's been instrumental in bringing trees to the attention of thousands of local residents. He's an advocate for North Texas trees, and he's good at it.

So, there he was in my landscape. What a golden chance to get tree management tips from one of the top guys in town. He had the time, and I had the tablet. Here are some of his feelings on local trees and how they fared following last summer's brutal weather.

In Mr. Houser's mind, it wasn't just the high daytime temperatures that did damage to our trees. Evenings when temperatures never dropped below 85 degrees were perhaps even more harmful. The trees were under stress all day and all night, and they never really got a chance to recover. Trees that aren't especially suited to high temperatures struggled most. From Mr. Houser's observations, silver maples were among the most impacted. "High water-use trees like cottonwoods and willows were hurt, and many bald cypress trees went into self-induced dormancy," he said.

The effects of Summer 2011 will continue to be felt for 5 or 10 years, Steve Houser feels. Root systems of many trees were damaged. As temperatures rise this spring and summer, those trees will find it hard to get enough water to their foliage, and some will begin to decline. The more time passes, the more difficult it will be to convince people that it ties back to the record summer. Local soils developed cracks 2 and 3 inches across, and that contracting of the clays did serious damage to trees' roots. Non native trees that are not a part of urban landscapes were especially hard-hit. Mr. Houser feels as many as 10 or 15 percent of those trees may have been lost.

The best thing we can do for our trees in spring and summer 2012 will be to water them attentively, according to Mr. Houser. He encourages deep soaking, almost to the point of runoff, then he urges us to wait until the soil is relatively dry before watering again. Most of all, he suggests not rototilling and planting flowers near the trunks of our trees. "People water their flowers way too much and it is not for the good of their trees. I'd much rather see them put mulch or a low-water-consumption groundcover near the trees' trunks," he said. He said he prefers purple wintercreeper euonymus or mondograss in such settings, then he once again emphasized that mulch is his first choice.

Relative to feeding our trees, Mr. Houser says that we need to be patient with them after last year, and that we shouldn't try to promote strong new growth too quickly this season. He recommends fertilizing healthy trees twice per year. His company uses organic fertilizers, so timing is not as critical, since the organics work over longer periods of time. For people using inorganic products, he suggests feeding once the trees are fully leafed out in the spring, with the second feeding in early fall. However, he says that if the trees are growing in a landscape setting, nutrients supplied to the turf will also be taken up by the trees, so special applications just to the trees may not be required.

Short Questions, Steve Houser's Answers:

How damaging are woodpeckers and sapsuckers? He says they can be tough problems for trees, especially thin-barked types like hollies. For oaks, pecans and other trees with thick bark, they're of less concern. Shiny, flickering objects do startle them, and they may be one of the better means of discouraging them.

Are lichens (mossy growth on branches) of any concern? "Not especially," Mr. Houser says.

Do you recommend pruning sealant for tree cuts? Mr. Houser says his crews routinely paint cut surfaces of oaks that are pruned after February 15 and before June 15. That's the prime time for entry of the oak wilt fungus, and sealing any cuts larger than 1 inch in diameter helps stop spread of the disease. However, at other times of the year, and with almost all other species, Mr. Houser rarely recommends sealing cuts.

What does a well-pruned branch look like as it heals? To that question, Mr. Houser stepped over to an old yaupon holly. He pointed to a prior year's trim, and he showed how the roll of new bark was forming symmetrically, coming in from all sides at the same rate.

Perhaps the strongest message of all from Steve Houser, however, is that we should involve certified arborists in all of our tree management work. Anyone can buy a saw and a truck, but that doesn't make him an expert. Certified arborists are men and women who have the credentials and the experience to do your tree work correctly. The website of the International Society of Arboriculture (ISA) allows you to find practicing certified arborists in your community. We're blessed to have many, and Steve Houser has been responsible for bringing many of them aboard.

In disclosure: Mr. Houser's business, Arborilogical Services advertises with Neil Sperry's radio program, magazine and website.