The Plant Doctor: Plant gladiolus bulbs in March or early April for colorful May blooms
Question: I would like to plant gladiolus for garden color and cut flowers. When do they grow best in Central Florida?
Answer: Most garden guides suggest gladiolus bulbs can be planted year-round throughout the state. If planted during the colder month, the bulbs are likely to remain dormant until warmer weather arrives. Talking from experience, March or early April planting appears best. The bulbs sprout quickly and flower by the end of May. They also avoid some of the common pests and diseases. You could plant a few bulbs every two weeks for a month or more for good flower displays to enjoy in the garden or cut for arrangements. When the tops of the plants decline, gladiolus bulbs can be left in the ground to eventually regrow or dug and stored until the next planting time
Q. My gardenia blooms are opening, but I find little black things inside. What are they, and how can they be controlled?
A. Flower thrips have invaded your gardenia blooms. These are common pests that mar the beauty of blooms, causing them to brown and decline faster than normal. Once in the blooms, thrips are often so numerous it is hard to shake or float them out. It is best to plan for these pests, and before the blooms begin to open, apply either insecticidal soap or natural spinosad containing insecticide. Repeat applications are likely to be needed following label instructions.
Q. Our landscape company applied mulch around yaupon hollies, and it is up to the base of the plants. How far back from the base should the mulch be added?
A. Rake the mulch back four to six inches from the base of all shrubs. Heavy mulch at the base of plants keeps the stems moist and could lead to rot problems. Too thick can also keep water and air from entering the ground. A mulch layer of about two inches over the root system of trees and shrubs is all you need to help maintain a uniform soil temperature and moisture level.
Q. There are a few bare spots in my St. Augustine lawn. Can I use the runners forming throughout the lawn to fill these areas?
A. Sprigs or runners of St. Augustinegrass can be used to fill the voids but get ones with roots starting to form. The secret to success is to cover the runners and roots a little and keep them moist. Another, and maybe more successful way to add turf to the bare areas, is with plugs or strips of grass. These can be cut from the good lawn areas. Often St. Augustine starts to run into flower and shrub beds, and strips two-to-four inches wide can be cut and added where turf is needed. Set the strips or plugs at normal turf level and keep them moist to be successful.
Q. When I prune crape myrtles, I use a sealer on the fresh cuts but the new growth continues to come out. What else can I do?
A. Trimming a crape myrtle branch stops the growth but does not prevent new shoots from developing along the stems. At this time of the year, the new shoots can quickly reform the removed portions. If you are considering keeping a plant contained, better trim each shoot back well beyond where you want the growth. Also, very few pruning paints or sealers are used today. They have been found of limited value and are not marketed to stop growth.
Q. We have lots of grass clippings and plant portions to turn into compost. I know you can purchase drums and bins to make compost, but is there another way?
A. Good old fashion compost piles were just heaps of organic matter left to decompose. This technique is cheap and still works today. You can go high-tech with various units that may make the process a bit easier, but a big pile of organic matter will still create a quality compost. Many like to keep the compost in wire, concrete block or wood-enclosed bins to keep it neat. Often two or more bins are made to turn the organic matter from one to the other over time, which speeds up the process. Plans are available from your local University of Florida Extension Office. Good compost is made by forming a foot layer of organic matter, then a thin layer of soil topped with manure or scattering of fertilizer. Make as many layers as your wish on top of each other. Then if you want to speed the process along, keep it moist but not wet and turn the pile every few weeks. Some gardeners turn the piles from one bin to another to have compost in varying degrees of decomposition.
Q. After a rose has bloomed and the petals drop, can I remove the star-shaped portion that remains? Will this affect the growth?
A. Snipping off the old flowers or rose hips helps promote more growth and flower buds, but there is a preferred method of removing these portions. Try to remove the spent blooms back along the stems to below the second set of five leaflets and just above the next set of leaflets. There is a new bud at the base of each leaflet ready to grow a new rose shoot, usually with a flower bud. Shrub roses are treated a little differently, and the old blooms are snipped off without much regard to the area of removal along the stems.
Tom MacCubbin is an urban horticulturist emeritus with the University of Florida Cooperative Extension Service. Write him: Orlando Sentinel, P.O. Box 2833, Orlando, FL. 32802. Email: TomMac1996@aol.com. Blog with Tom at OrlandoSentinel.com/tomdigs.
