I planted a trumpet vine seven years ago and it still hasn’t bloomed. It’s facing west and gets plenty of afternoon sun, and grows quite vigorously. How can I get this thing to produce flowers?
The Gardener’s Answer
Trumpet vine, Campsis radicans, is a fast-growing deciduous vine that can take several years to flower. This perennial vine produces flowers on new growth but it can actually take up to 10 years before you see your first blooms. There are a few reasons why older vines do not bloom, but we can rule out age and lack of sufficient sunlight in your case. Too much nitrogen fertilizer could be another possibility.
Trumpet vine does not need to be fertilized; it thrives in poor quality soil and will take up everything it needs from the existing soil. If you do fertilize, use half-strength recommendations. Do you prune your vine? If so, and you are cutting it back in the late spring, you may be removing potential flowers; the best time to prune is late winter or early spring before new growth begins.
That said, pruning can actually encourage flower production, so when early winter/spring arrives you can cut back some of the older, woodier growth to prompt blooms for next season.