GARDENER'S MAILBAG

Training shrubs as trees proves difficult

By Neil Sperry | Published Wednesday, August 29, 2018

Share this page...

Dear Neil: I have a vitex that is trained to be a tree. I have continually cut the limb sprouts off but more keep coming back. I’d like to start another one, but not for all that work. Any suggestions?

When we try to take a plant that is normally a shrub, such as a yaupon holly, crape myrtle or vitex and train it tree form, we’re at the mercy of that plant’s genetics. Vitex trunks don’t grow in straight lines so it’s hard to get them to develop in single-trunk form. They’re also very determined to stay as shrubs with generous supplies of side branches. What works best is to prune them very close to the surviving trunk so that none of the buds are left to send out new shoots. I prefer to train vitex to three or five trunks so that I don’t have to worry about trying to have a straight one. They still make attractive small tree-form plants, just not in lollipop form.

Dear Neil: I understand that fruitless mulberries are fast-growing trees. How fast do they grow, and are they suitable for our area?

As tree growth speed goes, they’re near the top, exceeded by willows, cottonwoods and a few other speed-burners. Like the others, they have short life expectancies and have many issues. They’re prone to borers and cotton root rot. They cast very heavy shade that will choke out your turfgrass, which becomes a problem when they thin and die out after 15 or 25 years. You’d be much better off choosing a tree such as a Shumard red oak or Chinquapin oak that grows two-thirds as fast but lives 25 or 20 times longer with far fewer problems.

Dear Neil: I bought two rose plants in a grocery store this spring. I’ve already tossed one, and the other one just sits there after producing four blooms last spring. Why would that be? Should I wait until fall to buy more roses at a nursery?

The plants you bought may have been really weak from their time at the grocery or they might have been spring-only bloomers. Some of the older varieties only bloomed one time a year. If you’re buying at a full-time retail garden center, fall would be a great time. Most nurseries close out most of their rose collections by Mother’s Day. You’ll find a bigger selection come spring.

Dear Neil: Why would small tree branches and twigs be falling? Leaves are attached and still green.

That’s probably the work of squirrels or birds. If you had told me the twigs were dead, I would have said twig girdler beetles. None are of any particular concern.

Dear Neil: Even though I have fertilized my St. Augustine and applied insecticide, portions of it are yellowed. What causes that?

It’s probably gray leaf spot, a fungal disease that is exacerbated by applications of nitrogen during the hot weather. You’ll see washes of yellowish grass within the lawn. On closer inspection, you’ll also see diamond-shaped gray-brown lesions on the blades and occasionally on the runners. You can probably find a fungicide that is labeled for leaf spots in turfgrass. Avoiding applications of nitrogen from mid-June through early September is your best way of stopping it.

Dear Neil: I planted a Japanese maple a few years ago. At that time it was in the shade of a hackberry tree, but a major branch of the hackberry broke and now the maple is in full sunlight. It has scorched badly this summer. Is there any way of helping it survive the sunlight?

Not really. Keeping it moist and avoiding high-nitrogen fertilizers are essential, but it’s still going to burn in our intense sun and high temperatures. If there’s any way you can transplant it this winter, you should move it into a shady location. Perhaps you can plant a large specimen of a better quality shade tree nearby to fill in the void left by the broken hackberry.

Have a question you’d like Neil to consider? Mail it to him in care of the Wise County Messenger, P.O. Box 149, Decatur, TX 76234 or email him at mailbag@sperrygardens.com. Neil regrets that he cannot reply to questions individually.

Leave a Reply. Note: As of March 24, 2011, all posted comments will include the users full name.

WCMessenger.com News and Blog Comment Guidelines

You must be logged in to post a comment.