Shade, crowding can take bloom off irises

Shade and crowding can keep irises from flowering.

Shade and crowding can keep irises from flowering.

Dear Neil: I have several iris plants (not bearded iris, but types with long leaves) that produce lovely foliage, but they don’t bloom. What can I do to get flowers?

A: They may need more light. While most Louisiana iris (and others of the many numbers of types of iris) will tolerate a good bit of shade and still bloom, flowering will be best if they get sun at least three-fourths of the day. If they’ve been where they are for many years, you might try digging and spacing them to lessen the crowding. Don’t trim their foliage unless it’s brown.

Dear Neil: Where in Texas can bougainvilleas be planted outdoors and have a good chance of surviving the winter?

A: Bougainvilleas can be damaged by more than just freezing weather. They’re not too happy with temperatures below 45, especially for prolonged periods. However, to answer your question, anywhere along the Gulf Coast, including warmer spots in Houston, San Antonio and southward. In the borderline areas where they’re marginally hardy, they’ll make it through some winters, but not others. Containers are always safe, as long as you have room for them inside or in a greenhouse. They get quite large as they age.

Dear Neil: I have a Lady Banksia rose that is about twice as big as the space I have for it. Can I cut it back? How do I know where to make the cuts?

A: Climbing roses including Lady Banksia are pruned immediately after they finish flowering each spring, so your timing is good. Start by removing any of the extremely long and straight stalks that always develop on this plant. Next, trim the more normal shoots that are not so straight back by as much as half. As a warning, however, the more you cut the plant the stronger the regrowth will be. That can come at the expense of flower production next spring. Lady Banksia roses are tall plants by their nature, so you really don’t want to try to maintain them at less than 8 or 10 feet tall.

Dear Neil: How should I handle my lamb’s ear once it finishes flowering? Do I cut it back to encourage new growth or just leave it alone?

A: You really don’t want lambs ear to flower at all. The blooms aren’t especially pretty, and they really drag the plants’ natural vigor down in the process. Snap them off as soon as you see the bud stalks, just as you do for coleus and caladiums.

Dear Neil: I heard a recommendation to mow my lawn at 3 inches the other day as a means of conserving water. Is that good advice? I have Bermuda grass.

A: Common Bermuda should be mowed at 1 to 1½ inches. To let it grow to 3 inches would cause it to become lanky and weak. The next thing you would see is weed invasion. It is much better to mow it at the recommended height, but to cut back on the frequency of watering and water more deeply when you do water. That will encourage deeper root penetration, and that is good for the long-term vigor of the turf. “Smart” controllers are getting better and better, and they’re good ways of saving water. We also need to make sure that our hoses, sprinklers, valves and fittings are all in perfect working condition. Those are more important means of conserving water than raising the mower height.

Dear Neil: What is the best time to divide hardy amaryllis?

A: Also called St. Joseph’s lilies, hardy amaryllis can be transplanted in the fall, or they can be dug and divided in spring, immediately after they finish flowering. If you choose the latter, don’t try to break them completely down to individual bulbs, but divide them into small clumps instead. Replant them at once, and water them thoroughly. You might also want to trim the green leaves back by half to cut down on their water demands for a few weeks.

Dear Neil: Our live oak has been covered with little balls stuck on every limb. What are these, and what can we do?

A: Oaks are subject to hundreds of types of galls. They are caused by insects that sting the plants’ tissues as they deposit their eggs. The good news is that they’re harmless. The bad news is, there is no chemical control for them. You have what is called woolly oak galls on your live oak. They are the result of wasp-like insects that swarm around the trees at certain times of the year. Curiously, not all live oaks are bothered by them. Other types of galls that you will see are large, puffy green galls on red oaks and woolly, small balls on the backs of your live oak leaves.

If you’d like Neil’s help with your plant question, drop him a note to Gardener’s Mailbag, PO Box 864, McKinney, TX 75070 or email your questions to


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