We carry 2 main types of fertilizers here at the nursery. The main one is called 12-6-8. These numbers all refer to the levels of nitrogen, phosphorus and potassium in the fertilizers. This granulated nutrient is mostly used in hedges, ornamental plants, and flowering plants. It is a very potent mix and proper care should be used when using this product.
You should wear gloves and avoid breathing in the dust. It should be placed like a ring around the entire plant on the ground about a foot away from the plant stems. It should not touch any other plants since it is so powerful, it will burn them up. This fertilizer is an above ground application and will dissolve on its own with normal watering.
The other type of fertilizer that we have is 11-4-11. This nutrient has been specially formulated for the use on palm trees. The same care should be applied when using this fertilizer as above. Both of these nutrients are commercial grade nursery professional nutrients. We have been in business for over 20 years and these are the best ones we have used.
You should really only fertilize when you see that the plant is not as healthy looking or the deep green color the plant used to have has become more light green to yellow, then thats a great sign that the plant needs food. If the plants are always a deep green color and looks great, then maybe a small amount of fertilizer once a year to keep everything looking at its best.
We carry two different size bags. A small quart size ziplock about 2.5 pounds for $4.00 and a large 50 pound bag for $45. A little amount of this fertilizer goes a long way. For example for small bushes less than 2′ is one handful going around the plant about 6″ away from the plant stems.