Are the Trees in Your Yard Healthy?

Fall is an ideal time for a check-up. Take these steps now and your trees will thank you, come spring.

The vibrant colors of fall foliage are the stuff of coming holiday cards, but the gold, red and yellow leaves shouldn’t distract from what’s happening to the trees shedding them. Autumn is a great time to check the health of the trees in your yard and prep them to get all green and flowery again next spring.

Experts say bare trees are, in some ways, easier to diagnose. The absence of leaves helps arborists get a clearer picture of potential problems, such as branches that are poorly attached, cracks in limbs and fruiting bodies on trunks (also know as “fungal conks,” such growths can indicate that the tree is rotting inside).

“You’ll see a lot of arborists walking around looking at the base of trees looking for mushrooms or things like that because they come out in the cooler weather,” says Steve Nagy, assistant district manager at The Care of Trees Dulles office.

November through February is the best time for pruning, he adds. “It’s healthier for the tree because you’re taking parts of the tree off and there’s zero disease pressure. There are certain trees that are really sensitive to that, so elms and oaks and things, we prune those in the wintertime because the fresh pruning cuts can attract insects and diseases” in warmer months.

Plus, cutting back limbs that are too big or too long reduces their chances of snapping in a snow or ice storm.

Fertilizing in the fall may seem counterintuitive, but Nagy says it can actually give trees a head start so they’re ready to regenerate when temperatures start rising again. “We always do our fertilizing in the fall – [mostly between mid-September and Thanksgiving] – because the tree can still take that fertilizer up,” he says. “That way, in spring, that fertilizer is up in the tree already and can really push new growth.”

Another way to protect trees in the winter – and, really, year-round – is to give them a nice bed of mulch.

“Apply a generous layer of wood chips at the base of the trees [in as wide a radius] as you possibly can. Even if you have to take out some turf or other vegetation to help revitalize the soil, that’s a good thing to keep your trees healthy,” advises Vincent Verweij, urban forest manager at Arlington County’s Parks and Recreation Department. “Just make sure it’s not piled on the trunk. That can cause rotting.”

Arlington County is home to about 755,400 trees, or 45 trees per acre – within the range of what a healthy forest would have, according to a recent study. The most common species include flowering dogwood, Virginia’s state tree; red maple; and white oak.

For the most part, those trees fare well against diseases and pests, Verweij says. “If your tree is in poor health because of lack of water or because its soil is not properly maintained or in good shape, that’s usually when some of the diseases and pests come in,” he says. “Most of our native diseases and pests don’t go after healthy trees.”

One sign that a tree has reached the end of its life is if more than a third of it has died off and pruning doesn’t help. A certified arborist should make an official assessment, Verweij says. He recommends looking on, Angie’s List and the Nextdoor app for insured and bonded businesses.

Ultimately, “there’s not a whole lot you have to do for going into winter. You don’t have to put them to sleep or anything,” he says, adding that tree owners don’t have to rush into any decisions. “If your trees are showing some serious signs of distress now – brown leaves or things like that – and they didn’t show them earlier in the year, one can probably wait until the next year to see if they need to do any work on them.”

Categories: Home & Design