Getting it to bloom

Why won't my Kentucky wisteria bloom? (and how to make it flower)

Also called Kentucky wisteria (Wisteria macrostachya).

More about kentucky wisteria

About Kentucky wisteria

Wisteria macrostachya · also called Kentucky wisteria · flowering

The hardiest wisteria in cultivation, native to the central-southern United States, tolerating temperatures to -40°C/-40°F and reliably hardy in USDA zones 3–9. Bears mildly fragrant, blue-lilac to purple flower racemes of 8–15 cm in late spring to early summer, often re-blooming later in the season. More compact and better-mannered than Asian wisteria; ideal for cold-climate gardeners.

Plant type: flowering

Watch for — Failure to flower in early years: Grafted cultivars such as 'Blue Moon' flower in two to three years; seedlings may take up to ten years. Ensure full sun, avoid nitrogen-rich soil, and consider root pruning in late winter to stress-trigger flowering in reluctant mature plants. Re-blooming cultivars need good sun and twice-yearly pruning to rebloom reliably.

The reasons kentucky wisteria isn't blooming

Almost every non-blooming kentucky wisteria traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding kentucky wisteria a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get kentucky wisteria to flower

Maximise sun. Give kentucky wisteria the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for kentucky wisteria and get the feeding right with the kentucky wisteria fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Kentucky wisteria flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full kentucky wisteria care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Kentucky wisteria blooming — frequently asked questions

Why won't my kentucky wisteria flower?

Kentucky wisteria blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make kentucky wisteria bloom?

Give kentucky wisteria the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does kentucky wisteria normally bloom?