Hackberry trees best left in nature; in back yards, they can cause weeds


We are looking for a fast growing shade tree to provide shade on the southwest corner of our house. Will a hackberry tree work for that purpose?

The hackberry tree (Celtis occidentalis) has some very good qualities and will work for that purpose, however it has several shortcomings. The hackberry is a native tree that appears similar to the American elm tree. It is a fast grower and maintains a vase shape that is ideal for providing shade around homes. It is also a strong tree that is not prone to breakage.

On the other hand, small galls often disfigure hackberry leaves. While the galls cause no permanent damage, they cause trees to begin shedding their leaves in late summer or early fall. Also, hackberry trees provide an abundance of black fruits that are great food for wildlife, however they can also cause a significant weed problem in home gardens. The hackberry is a great tree, but I think it is best used in natural areas and parks. While there is no perfect shade tree, I would consider planting one of these trees: red oak, willow oak, sugar maple, red maple, Zelkova tree, or sweet gum (select a non-fruiting cultivar).

I have a large overgrown clump of bearded iris that need to be divided. Should I divide them now or wait until fall?

Irises are very tough plants. I have transplanted them in early April with success and also transplanted them in late October with success. How-ever, these are not the ideal times to divide iris. Most experts suggest dividing and transplanting the rhizomes (swollen roots) between mid summer and early fall (July- September).

If you delay transplanting until the summer, you can enjoy their spring blooms, and meanwhile you give the plants a chance to store food reserves in their rhizomes. The plants will use these food reserves to re-establish themselves after planting.

By planting between July and September, you also give plants a chance to get rooted before winter sets in. This will prevent the plants from being heaved during the winter months and will allow them to flourish the following spring.


1. Do not delay cutting back large overgrown plants. Plants that are pruned hard now will have an opportunity to re-grow before the hot summer months begin.

2. Take advantage of any dry weather to turn over beds and prepare your soil for planting. Wet soil should not be dug or tilled.

3. Pull winter annual weeds such as chickweed and henbit before they produce flowers and seeds. This will prevent them from returning next year.

Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site www.hgic. umd.edu.

Copyright © 2020, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad