AnswerThe key with a magnolia tree is the amount of fertilizer you are using. If you planted a tree in an area that is surrounded by grass, the fertilizer from your lawn is more than adequate for the tree. The run off from the yard will assist the tree and the tree will not needs its own application of fertilizer. If it is in a rocky area not surrounded by grass, it would be a good idea to use an organic fertilizer.

AnswerTree Fertilizer spikes might would give it a boost but you can also try fertilizers that are more rich in nutrients for the plants. They carry a wide variety of fertilizers at Lowes.

AnswerIf your palm tree will not grow, there are a few steps you should take before you should look into a different fertilizer. The first step would have to be, are you planting it deep enough? Second, would be, is the palm tree getting enough sunlight? Thirdly, it would be is the palm tree receiving enough water? And to answer your original question, there are specific fertilizers you can use. I would suggest going to your local gardening shop and see what they might suggest as the area might need different nutrients in the soil.