You pound these spikes in the ground near your woody plants and they provide food for a full year. They certainly made my shrubs happier!
I have terrible, terrible west Michigan sandy soil. Let me rephrase that. I have beach sand with a tiny bit of clay and humic material in it. Growing things is a real challenge. Yet I keep hoping for some flowering shrubs to border my yard, when I can keep the rabbits and deer from eating them.
These spikes have made a definite difference in a sand cherry, forsythia, flowering quince, and a white birch tree. I’m not saying that they don’t work on other things, but those are the places I have used it.
The spikes are 16-8-8, blended specially for deciduous woody plants, and are supposed to be particularly good for flowering shrubs. I think this is true, because mine rarely bloomed until I started using these. They are a compressed “tablet” with a pointed end. Sort of like a huge pill.
Once a year, either spring or late fall, you water the ground around the plant very thoroughly so it is soft. Then you put the provided plastic cap over the end of a spike and hammer it into the ground (no closer than 30 inches or you will burn the roots). When it is pounded in to ground level, remove the cap and pound it down another 2 inches. Now the fertilizer is in the root zone (not on the surface of the ground), and will release slowly over the following months.
Once you open the box you do need to use the spikes soon or they begin to lose their potency. So only buy what you are going to use at any one time.
Drawbacks are few- I have had a spike break in the box, but this isn’t a real problem. Sometimes I can just re-stack the broken pieces and pound them in as one, or pound them in separately.
This package happens to be Jumbo size. If you have very small shrubs that are just starting, look for the regular size.