Giant ginger panache, a surprise

Question: We moved into an older house and found this flower opening on a plant with large green leaves. What is the plant and the care required?

Answer: What a wonderful surprise to find the giant plume of ginger in flower. It belongs to the genus Cucurma and has a relative often called the hidden ginger. Your species flowers early and produces stems with foliage up to eight feet tall. Hidden ginger grows much more slowly. None of these gingers are edible. Keep your planting moist and filtered in full sun. Eventually, the plant cluster will spread and require containment. This might be a good plant to share with friends. Fertilize occasionally with a slow-release product in early October. The plants die back in late fall and winter and resume growth in early spring when they begin to flower. The flowers last for several weeks then diminish.

Q. I have several southern magnolias that grow large with branches all the way to the ground. If I cut off some lower branches, what can I plant under the trees?

A. Reconsider removing lower limbs as southern magnolias are very attractive with branches close to the ground. In addition, the root system is so dense that it is difficult to grow plants under the branches. If you decide to remove some branches, simply adding mulch would be a good idea. Otherwise, some tough, long-lasting plants that could compete with tree roots include bromeliads, dwarf Trinette schefflera, or Asian jasmine. All of these need or can tolerate shade from magnolia foliage. Start these plants a few feet from the trunk where the roots are a little less crowded. Adding shade-tolerant plants to containers would be another option.

Q. Several of my spathiphyllum fill their containers. Should I give them something bigger or divide the plants to make more?

A. Most spathiphyllum, also known as peace lilies, are now in bloom, so you can wait a month or more to decide how to manage the plants. If you select a container about two inches larger in diameter, the plants should have enough room to grow another year and remain attractive. Dividing the plants gives you two or more of each spathiphyllum, but they will need time to recover. Maybe you divide a plant or two and move the others to larger containers. Dividing the plants is not easy because they grow in cluttered clusters of stems. Use a serrated knife to divide the plants into two or more sections. You will cut off certain portions of plants that can be thrown away. Then give each new plant a container about two inches larger and fill it with potting soil. Keep it moist and your new plants should resume growth. Fertilize with a slow-release product for container plantings during warm months, following label directions.

The Plant Doctor: Unwelcome garden visitors are back again

Q. The leaves of our corn plantations are shredded by an insect. What is it and necessary control?

A. Look in the center of corn foliage whorls and you might find fall armyworms. No matter what its name indicates, this insect can be present all year round. They appear to hide during the day and feed at night by chewing leaves which can make them appear shredded. Some natural controls may be at work, especially if you can't find these larval stages of a butterfly. Wasps often fly to extract the larvae and stuff them into their nests. If no larvae are found, no control is necessary. If you find a few Legionnaires, they could be controlled by eliminating them manually. Alternatively, when spraying is necessary, use a natural insecticide such as a product containing Thurcide BT or spinosad found at local independent garden centers. Follow the following instructions on the label.

Q. I have a beautiful gardenia bush that has green leaves and flower buds but none have opened. What should I do to help the plant flower?

A. Wait a little longer and your gardenia should be in full bloom. Although the shrub is full of fleshy buds, the main flowering season doesn't begin until late April or May. The best displays can last a month or more, then many varieties open sporadic flowers throughout the summer season. Gardenias are high-maintenance plants that like to be moist, have mulch over their root system and need three to four feedings per year. If the leaves turn yellow even with this good care, try feeding with Epsom salts following the label directions. They are susceptible to mealybugs and thrips which can be controlled with natural sprays available at your local garden center.

Q. A friend just told me that newspaper can be used as mulch. How to best use it in the landscape?

A. Actually, only the gardening section works – well, maybe that's not entirely true. Many gardeners use all portions of the newspaper to prevent weed growth and conserve moisture. It may be best to only use a few layers or drill more holes every few feet. Thick layers could prevent water from penetrating the soil and reaching the roots of your plants. Newspaper decomposes quickly, so you may need to replenish this mulch or add a layer of other mulches on top.

Q. I have a crepe myrtle tree about 20 feet tall and lots of new leaves. Will I damage the tree if I cut it back heavily now and will it still flower?

A. Go ahead and relax. You won't stop the crepe myrtle from growing or opening flowers for the summer. Flowering may be delayed by late pruning, but the plants are resilient and should produce lots of color from the many shoots. Could we talk about lighter pruning which would only remove the ends of the branches full of pods? Or perhaps you could selectively remove branches toward branch corners or trunks to more naturally reduce tree height. Such conservative pruning helps maintain the natural shape and beauty of crepe myrtle trees and shrubs.

Tom MacCubbin is a Distinguished Urban Horticulturist with the University of Florida Cooperative Extension Service. Write to him: Orlando Sentinel, PO Box 2833, Orlando, FL. 32802. Email: [email protected].