Neil Sperry

Neil Sperry: A warning against popular shade trees

Purple plums have the shortest life expectancy of all shade trees. They can live about 5 years, and are susceptible to peach tree borers, bacterial stem canker and weak roots.
Purple plums have the shortest life expectancy of all shade trees. They can live about 5 years, and are susceptible to peach tree borers, bacterial stem canker and weak roots. Special to the Star-Telegram

I collect garden questions. I do it for a living, and just about everywhere I go, the second most common question I’m asked is, “What’s the best fast-growing shade tree?”

I used to flinch when that call came in on my radio program. I feared my answer wouldn’t appease my fellow gardeners — and I was usually right. But I’ve stayed steadfast in my beliefs and, through the years, have tried to plead my case.

A more accurate phrasing might be that I’ve become a character witness on this topic, and I’m here today to testify to how these “characters” have behaved during the four-and-a-half decades that I’ve been taking this question from North Texans seeking shade in their yards.

To the extent of my training and experience, I swear to tell the whole truth and nothing but the truth, so help me God.

As I imagine the conversation going, the prosecutor begins: “Mr. Sperry, you’ve been growing, observing and advising about North Texas trees since 1970. Is that correct?”

“Yes, sir,” I answer. (I know to be brief and direct.)

He points with a scowl to the other side of the courtroom, saying, “And this person says all he wants is a good, fast-growing shade tree. Is that what you’ve heard?”

“Yes, sir,” I repeat.

“But I’ve seen you write and heard you say, Mr. Sperry, that there is no such thing as a good, fast-growing shade tree. Have you said that?”

“Yes, sir,” I concur, once again.

“We have here your list of about 20 fast-growing trees. I’d like you to tell us why you don’t consider these to be good shade trees. And while you’re at it, please tell us how long, on average, each of these is likely to live.”

Now I’m in familiar territory. Dutifully, I run down my list of fast-growing shade trees and the problems they have:

Purple plums: average life expectancy of 5 years; peach tree borers, bacterial stem canker, weak roots.

Willows: 6-8 years; cottonwood borers.

Flowering peaches: 6-8 years; peach tree borers.

Ornamental pears: 10-20 years; cotton root rot, extremely weak branching/breakage.

Leyland cypress: 10-20 years; extreme susceptibility to fatal vascular bacterium, growth splays out and is difficult to control.

Arizona ash: 10-20 years; ash tree borers.

Siberian (Chinese) elm: 15-20 years; cotton root rot, elm leaf beetle, wetwood.

Eldarica (Afghan) pine: 15-20 years; intolerant of waterlogged soils (It’s from a part of the world that gets 10 percent as much rain as we’ve had here this year.), incurable vascular disease.

Mimosa: 15-20 years; mimosa root rot, cotton root rot, mimosa wilt, mimosa leafroller.

Fruitless mulberry: 15-25 years; cotton root rot, borers, high water needs, vascular diseases.

Chinese tallow: 15-25 years; freeze damage or dieback, iron deficiency, invasiveness.

Silver maple: 20-30 years; extreme iron deficiency, high water needs, cotton root rot, leaf and vascular diseases.

Catalpa: 20-40 years; catalpa worms strip foliage, leaf scorch, great deal of litter.

Varnish tree: 20-40 years; excessive litter, cotton root rot.

Green ash: 20-40 years; emerald ash and other borers, aphids, cotton root rot.

Lacebark elm: 20-40 years; cotton root rot, weak roots, other leaf diseases.

Fruiting mulberry: 25-35 years; leaf diseases, extremely messy with wet fruit litter, extremely invasive.

Sycamore: 30-60 years; anthracnose vascular disease, high water needs, leaf scorch, extreme litter.

Hackberry: 30-60 years; extremely brittle wood breaks in wind, ice storms (not especially attractive either)

Cottonwood: 30-60 years; cottonwood borers, cotton root rot, leaf scorch, high water needs, very shallow roots.

The prosecutor continues, “So, Mr. Sperry, this list makes it clear that you’ve disparaged just about all of the fast-growing shade trees. Do you have a list of types that may not grow quite that quickly, but that would offer superior tree quality?”

“I do, sir,” I answer quickly.

Happily, I offer my short list of trees that grow almost as rapidly as the “trash trees,” but which can be expected to live 10 or 20 times longer — and with far fewer problems. This list is the most important part of my “testimony.”

Here’s the summary: live oak, Shumard red oak, chinquapin oak, bur oak, cedar elm, pecan (best: Caddo variety) and Chinese pistachio.

“If people are willing to drop back another few miles per hour in growth rate,” I add, “male (non-fruiting) gingkoes and magnolias are great, too, although somewhat slower to reach maturity.”

Thinking I’ve concluded my shade tree testimony, I start packing up to leave, but the judge has a final inquiry: “Mr. Sperry, you said this was your second most commonly asked question. What, pray tell, is the first?”

“That’s easy, your honor,” I answer. “It’s, ‘What can I do to get grass to grow beneath my trees?’ 

In the interest of time, I tell him that the answer to this mystery can be found on my Facebook page, in the FAQ section of neilsperry.com and in every book that I’ve written.

“I see,” says the judge. “Court dismissed.”

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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