Palm and papaya problems may be water, fertilizer
Q: I planted 7 queen palms in decomposed granite with the help of jack hammers 20 years ago. There are rocks over the roots that have been gently cleaned with Roundup over the years. The palms have looked really good all these years. However, since last fall they have not looked too good. What do I need to do to make them lush and healthy again? Obviously water has been a problem. What about fertilizer? One palm has its fronds leaning to one side. I sprayed it with copper fungicide twice and it still looks the same. I cannot even think of replacing them. Pease advise? — Anneliese
A: Since you have been using it for years, I am going to assume that no Roundup has reached the roots of your trees. Queen palms are a tropical palm, unlike the Mexican fan palm which is a desert palm and thrives here with little water. Queens need lots of water and regular fertilizing with palm food. They require adequate amounts of nitrogen, magnesium, sulfur, iron, copper and especially manganese. No, this is not a misprint; magnesium, and manganese are not the same thing. Both are micronutrients and both are needed for the health of queen palms. The best way to get all of these nutrients at one time is to get fertilizer formulated especially for these trees. It is available in spikes that release nutrients slowly over a period of several months and should be placed around the perimeter of the tree several inches under the ground about 2 feet from the trunk of the tree.
If you are watering and fertilizing the trees and they are not responding it is possible that the PH of your soil is too high and is preventing the tree from taking up the nutrients it requires. This is a common problem in the alkaline soils in this area. It can be remedied with a commercial soil acidifier or a solution of 1 cup of pool acid (muriatic acid) to five gallons of water. It will probably take about 20 gallons to treat the entire root ball of a tree this size. If you try this, be sure to water very thoroughly the day before to guard against burning.
Q: I have two papaya plants which I originally planted in 15-inch pots last year. They did very well but seemed to outgrow the pots. I planted them in the ground and this winter the temperatures here in San Marcos got below 45 degrees a few times. They started looking very bad so I went to the local nursery and purchased insulation cloth, as suggested by them. I draped the plants at night when the temperature would be low but they seemed to really lose their leaf shape and now all I have are sticks for stems. I planted them back into pots again since they did so well before. I really want to save them. Do you have any suggestions? — Maureen
A: I do have a suggestion, Maureen, but it is just that. It may not have been the temperature that damaged your papayas. They are very susceptible to root rot and given the amount of rain we had this past winter that may be what caused the problem. They may leaf out again and if you put them in the ground again. Make sure that the soil is well drained. Good luck.
Rose Crawford is a certified garden consultant and a master composter who lives and gardens in Vista. She answers your gardening questions every other week. E-mail questions to firstname.lastname@example.org