i would get them out.. and throw them away ...

and simply use a water soluble fertilizer in your water ... diluted to 10 % every time you water ....

they are USELESS ... and marketing gizmo .. and further.. USELESS ...

THROW THEM AWAY .. live and learn ...

ken

ps: i did mention USELESS????

pps: they are even more useless in mother earth ... how in the world do you even know if you are pounding them in near feeder roots?????

Fertilizer spikes of any kind are a bit silly. If you think about it, plant roots - those parts of a plant responsible for the uptake of necessary nutrients - are not centered in any prescribed location from the trunk or base of the plant. They radiate outward from the base and that's how fertilizers should be supplied - not as a single spike here and there but as a radiated broadcast throughout the root zone. Now if you were to grind them up and spread them uniformly over the root zone they would be of some benefit but otherwise, they are pretty much a waste of money as ken states.

The other thing is that the fertilizer dosage for trees is far too strong for other, smaller plants, especially bulbs. That's why they make different spikes for different types of plants :-) I would also recommend removing them from the pots - when they do start to disintegrate with water and release the nutrients they could very well overwhelm the bulbs and certainly damage the roots should they come into contact with them.

Bulbs generally need minimal additional fertilization if newly planted. They have all the nutrients they need for proper growth and flowering stored in the bulb. It is in subsequent seasons that fertilizing may be appropriate, especially if the bulbs were not allowed or provided correct aftercare after blooming.

Are they that bad? Oh my. The label description sounds pretty professional. They suggest to arrange the spikes in circles surrounding the trunk. The number of spikes per tree is dependent upon the thickness of the tree. There is another spike for conifers and that is deep green, in stead of light green.

They actually work very well for their intended purpose...to enlarge the billfold of the shysters why sells them to those that don't do the research before buying.

What Brandon said. Those things are useless if you're looking to fertilize something.

As described already you want your fertilizer spread out over the whole root system instead of concentrated in columns.

I would imagine that where the spikes are driven into the ground, they burn out all the feeder roots in the immediate area. One spike in a pot would be way too much. Spread out, as Ron says, is the way to go. The fertilizer covered with a light mulch or top dressing is even better. It moderates the rate at which the fertilizer is dissolved. Fert on top of the mulch breaks down the mulch at a faster rate than if it wasn't used. I want the fert to be absorbed by the roots, not the mulch.
All that aside, I haven't used fertilizer in my garden in over 30 years. I just use it sparingly in potted plants. Woodchips is my soil conditioner of choice.
Jujujojo, take the spike out, grind it up and lightly spread it about where you need it. As GardenGal says, bulbs don't initially need fertilizer.
Mike...with probably more info than is relevant to the original question.
;-)