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Ask Dr. Hort: Fungus diseases cause similar problems with St. Augustine grass

Philodendron growths are aboveground roots

Q: We have three philodendrons with erect trunks that keep growing taller (they are now 3 feet), with long tubelike growths that look like roots growing from the trunk to the ground. Am I supposed to trim off these tubes? These plants are about 12 years old. Thanks. Gerri

A: It sounds to me like you have self-heading philodendron, Philodendron bipinnatifidum, previously named Philodendron selloum. The tubes growing out of the trunk are called aerial roots because they appear aboveground. Don't cut them off. Being a rainforest plant, it prefers broken shade for best appearance, but will grow in full sun with slightly smaller leaves more yellow in color. Use a palm fertilizer to keep it lush and green, as it loves magnesium and potassium. Keep it evenly moist. It will grow horizontally unless you stake it. In its native habitat it creeps along until it finds a tree, and hangs on with its aerial roots as it shoots to the canopy.

Fighting fungus diseases in St. Augustine grass

Q: We have used a lawn service for 15 years. In the last three years we have been troubled by "brown patch" in a sunny area. We have called the lawn service several times and they apply potash to the affected area. It has never totally been resolved and we have resodded the area with Floratam twice. Now the brown patch is back — and spreading.

We were told to be restrictive when watering this area, but so far nothing has helped. Do you have any suggestions? Gigi Bressie, Tarpon Springs

A: Are you sure that you have brown patch? There is another culprit called "take all root rot," which looks similar. Both are fungus diseases that cause St. Augustine to yellow and then turn brown. The difference: Brown patch results in the death of the leaves. The blades turn black where they join the stolon, or runner. "Take all" causes the death of roots. The roots become black and brown with few healthy white roots.

Irrigate sparingly, use only slow-release fertilizers with micronutrients such as iron and manganese and mow as high as possible. Then, if needed, treat with fungicides containing myclobutanil, such as Spectracide Immunox, Fertilome F-Stop and Green Light Fung-Away. These products help control both diseases, but if it is "take all," professional products such as Heritage or Bayleton may be necessary. They are very expensive. With any of these products, timing is everything and following label directions is a must. You might be better off hiring a professional pest control company to get a positive identification. If all else fails, perhaps it would be a beautiful spot for a butterfly garden or, better yet, a vegetable garden.

Christmas berry plant pretty, but an invasive

Q: We just bought a parcel of land where there had been a nursery. There are many escapees of various plants and remnants of what must have been gorgeous gardens, but there is one plant I can't identify.

The shrubby plant doesn't seem to mind cold, grows in heavy shade as well as a fair amount of sunlight, and has thick, shiny evergreen leaves and brilliant clusters of red berries that hold all winter.

They are gorgeous, tough plants, but I'd love to know what they are. Thanks for your expertise. Denise

A: The plant in your photo is coral ardisia, sometimes called Christmas berry, Ardisia crenata. There's good news and bad news. It is indeed beautiful and grows to 6 feet. But the Florida Exotic Pest Plant Council has placed coral ardisia on its Category I list of invasive plants, those "altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives." Its ability to do so is precisely because of the reasons you noted: It thrives from sun to shade, it withstands cold and has abundant seed production. Coral ardisia's scope is primarily within hardwood hammocks in North Florida. Other beautiful but invasive plants include Brazilian pepper and water hyacinth. Learn more at fleppc.org.

Need help? Dr. Hort (Greg Charles) answers questions about garden problems. E-mail him at drhort@tampabay.rr.com or mail questions to HomeLink, Features Department, St. Petersburg Times, P.O. Box 1121, St. Petersburg, FL 33731. Describe problem in full, and include your name, city of residence and contact information. If possible, include a good-quality photo. Fuzzy ones won't do. Photos cannot be returned.

Ask Dr. Hort: Fungus diseases cause similar problems with St. Augustine grass 05/07/11 [Last modified: Saturday, May 7, 2011 5:30am]
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