Question
I have 2 double robellinis around my pool with some fox & christmas palms and ever since the robellinis were planted they seemed a little on the thin side with respect to the quantity of new shoots and they also seemed to be a lighter green than some I see around town. Now I have some new shoots that are coming out 25-50% brown/dead. Not sure what they need? I have fed them a few times with palm food over the last year. I want to prevent the brown/dead shoots, produce thicker shoots with darker green color. Largo, Florida.


Answer
If your palms are located in a windy area, the leaves could be drying out; moving the plant to a more sheltered area could solve the problem. Roebelenii palms prefer a moist, but not wet soil, and a humid environment.    Water when the soil feels dry in the top inch or so. To increase humidity around the plant, mist the leaves daily or set the pot on stones in a wide saucer filled with water so that the bottom of the pot is not sitting in water.  This helps provide humidity without the risk of the container bottom sitting in standing water which could lead to root rot.

It could possibly be a nutritional deficiency although this is less likely in potted plants that are growing in a good potting soil.  There are fertilizers made especially for palms and you should be using them as directed, especially in the summer.

I am adding this from Dept of Agri in FL...
At least one of your palms is in the category

Two types of palms in Florida ?the Canary Island date palm and the Sabal palm (shown here) ?have the new disease. They suspect that plant-hopping insects feeding on the trees?nutrient-carrying tissue carry the phytoplasma. Photo Courtesy of Central Florida Palm & Cycad Society (website)
Florida抯 state tree is dying, and there抯 no cure. A disease that抯 killing sabal palms was reported in Hillsborough County on Thursday. However, University of Florida researchers who used DNA testing to confirm the deadly phytoplasma don抰 know how it is spread or how to stop it.
   
 
揑t抯 a new disease, and there are no easy answers,?said Hillsborough County forest extension agent Rob Northrop.

They do know, however, the tall, slender trees that are the source of 搒wamp cabbage??the edible hearts of palm ?are turning brown and dying.

The disease has been confirmed in sabal palms along Brandon Parkway, in Ruskin抯 E.G. Simmons Park and along U.S. 41 south of the Alafia River, Northrop said. It was found in Manatee County two weeks ago.

It抯 hard to determine how widespread the disease is because there are no field tests, and it can抰 be diagnosed by simply looking at the trees, Northrop said. Confirming the disease requires expensive DNA testing. However, the disease is probably caused by the same phytoplasma ?a bacterium without a cell wall ?that抯 killing four other palm species: the Canary Island date palm, the edible date palm, the wild date palm and the queen palm, UF researchers said.

Because each tree can cost thousands of dollars, Northrop suggests that people stop planting palms until more is known about the disease. For now, homeowners who find withering palms in their yard should not immediately remove the tree, Northrop said. Instead, disinfect pruning shears between trimming each palm and consider hiring an arborist to inject an antibiotic. The antibiotic, called TreeSaver, is inexpensive, but Northrop suggests hiring an arborist to inject it correctly. That could cost a couple hundred dollars and should be done three to four times a year.

The antibiotic isn抰 practical on a large scale, said Monica Elliott, a UF plant pathology professor based in Fort Lauderdale, so there抯 no real solution yet for stopping the disease.