I have a common lilac bush that has not flowered in 2+ years. It is in full sun. It is growing tall (about 4 feet) with lots of green at the top of the bush with long woody stems. How do I prune this so it gets that rounded shape with more blooms and green lower down? I understand you need to prune after it blooms, but is hasn't so where do I start?
May I offer my experience with a lilac hedge around a large corner-lot residential street property in Nova Scotia I used to own: It was a well-established hedge when we moved in, although not extremely groomed or anything, and bloomed at the top, then about 6 feet high. I had small children, then teenagers, plus a library job, and was too busy to garden, so it just got left on its own. Then, I noticed about 3 years before we moved for retirement to Saanich BC that the hedge was about 8 feet tall, rather top heavy with scraggly feet and not that full of bloom. So I asked around, and our lawn-cutter said to prune it off to about 3 feet off the ground. I did so, what a mess. My neighbours were cross with me. I fertilized it and added some compost around it. It stayed alive, but looked very sad. Then, about 4 years after this operation, one year after we moved, what did the lilac hedge do? It bloomed like crazy. I have learned that all this work with shrubs requires a long-term view: what you do today, or tomorrow, you will reap in 3 or 4 years' time. Same thing with two standard-sized variegated pink-flowering Weigelas I planted about 3 years before deciding to move: they were small and scraggly but carefully fertilized and watered, etc., until we moved, then the year after it flourished and the neighbours were so impressed they all told me about it, and the person who bought the house moved them up to their patio from their original location street-side to enjoy them more.
