When to fertilize.

[tuffy]

Can you tell me when to fertilize my tulips and roses and iris's the tulips are about 21/2 inches high now iris's just coming up no movement on the roses. not sure what zone I'm in but I live in n/e Missouri.

 

[slownsteady]

You might find this article helpful: https://www.gardenguides.com/100545-fertilize-flowering-landscape-plants.html