TreeHelp Palm Tree Magnesium Spikes Used to treat magnesium deficiencies in your palm tree. Specially formulated to provide magnesium in a way your palm tree can easily absorb. Easy to use, high quality, slow-release spikes last for up to 12 months. Magnesium deficiency causes yellowing, withering and reduction in leaf size. The spikes can be used for established palms, newly planted palms and potted palms.