Jobes evergreen spikes contain fertilizer that is slowly released into the soil around the evergreen. These fertilizer spikes last around 3 months before you will need to replace them. The benefits of slow-release, spike fertilizers are two-fold. You lower the risk of burning your evergreen through too much fertilizer applied at once, and you save yourself some time and effort--when you use these fertilizer spikes, you do not have to mix fertilizer and pour it around the plant.
Estimate the evergreen's trunk diameter. If using these for a tree, you will need one fertilizer spike for every inch of trunk diameter, according to Gardenharvestsupply.com. If you are using these spikes for an evergreen shrub, use one spike per 3 feet of height.
Place the spikes at equal lengths apart around the tree. You'll be inserting the spikes at the drip line (where water runs off the outer leaves) of the tree and not near the trunk. If using these on a shrub, use a ruler to measure out 4 to 5 inches from the trunk/stem.
Place the spike point down and gently hammer it into the soil ( when you finish, the top of the spike should be below the top of the soil) with a mallet or hammer. If the ground is hard and dry, you may need to create a starter hole using a small hand spade.
Water around the tree or shrub, after inserting the spikes, to give the fertilizer a good start.