Q: I have a queen palm that appeared to stop growing, and the existing fronds have drooped. The top looks fried.
B. P., Miami
A: Queen palms are very susceptible to “frizzle top,” which is a nutritional (manganese) deficiency. To correct the manganese deficiency, begin your first treatment in spring — it’s too late in the season now. Use manganese sulfate at the rate of two to four pounds per palm four times per year spread over the soil under the palm canopy. Applications can be repeated every two to three months, depending on the severity of the problem and soil type. However, an improvement in the new growth may not be seen until three to six months after applications. You will also need to apply 8-2-12 + 4 percent Mg as your routine fertilizer.
To prevent this problem, use “palm special” type fertilizer (8-2-12 + 4 percent Mg) and follow the rate on the bag. Be aware that there are other palm fertilizers so check to make sure it’s 8-2-12 + 4 percent Mg. Based on University of Florida research done in South Florida, this is the only type of fertilizer that should be used within 50 feet of landscape palms. So, if you fertilize nearby plants such as the lawn, use the palm fertilizer instead of a lawn fertilizer.
Manganese sulfate and 8-2-12 + 4 percent Mg fertilizer is available from some garden centers, and fertilizer companies and distributors in South Florida. If you need a list of these companies, call your local UF Extension office (Broward 954-357-5270, Miami-Dade 305-248-3311 x228, Monroe 305-292-4501, and Palm Beach 561-233-1700).
After treatment, it will take several months to see new growth that is healthy. If the deficiency is too advanced, the palm will probably need to be replaced.
Manganese deficiency is very common on alkaline soils, but can occur when soil temperatures are cool. Most species of palms can be affected, but queen palm, royal palm, paurotis (Everglades) palm, pygmy date palm, and African oil palm are particularly susceptible.
To learn more about palm problems, please visit this UF website: http://flrec.ifas.ufl.edu/