Question
i have lilacs that are about 5 yrs old. when i planted them they were flowering they have not since then. is there something i can feed them to make them better

Answer
Hi Barbara, High phosphorous fertilizer like 0-45-0 will help encourage flowers. I'd like to apply it late summer to early fall on lilacs.  Other things to check...
They need full sun, are they getting it?
Many are prone to powdery mildew which can destroy the flower bud, could this be happening?  Jim