Fertilizer is often part of the problem, but usually because a wisteria is getting too much nitrogen rather than too little, and excess nitrogen boosts leafy growth while reducing flowering. A vine putting out plenty of long, green shoots with few or no hanging flower clusters is showing that imbalance.

How does too much nitrogen stop wisteria from flowering?

Nitrogen drives shoot and leaf growth, so a heavy dose pushes wisteria into making more vine instead of more flowers. Wisteria generally does well without heavy fertilization, which means extra feeding in hopes of a better bloom tends to work against it.

What else keeps a wisteria from blooming?

Too little sun and too little pruning can also hold flowering back. Wisteria prefers full sun, and regular pruning in late winter or early spring encourages flowering, which matters most on a fast grower such as Japanese wisteria, a vine that can reach 30 feet.

How should a wisteria be fed so it blooms?

Lightly, in spring before bloom, with little or no fertilizer while the flowers are open. Where a quick release feed pushes long, leafy shoots, TreeHelp Premium Fertilizer: Wisteria releases its nitrogen gradually across the growing season from a single spring application.

Frequently Asked Questions

Can lawn fertilizer near the vine affect blooming?

It can. Turf fertilizers often carry a high dose of quick release nitrogen, and excess nitrogen in wisteria increases growth at the expense of flowering.

Should a wisteria be fertilized while it's flowering?

No. Fertilizer is best kept to a minimum during bloom and applied before the flowers open instead.

Is there a second time of year to feed wisteria?

For Japanese wisteria, yes. Late summer until the leaves drop is a second feeding window after the spring application.

What soil suits wisteria best?

Well drained, fertile soil that is slightly acidic to neutral, though wisteria adapts to a range of soil types.