Getting it to bloom

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

Also called American wisteria, Atlantic wisteria (Wisteria frutescens).

More about american wisteria

About American wisteria

Wisteria frutescens · also called American wisteria, Atlantic wisteria · flowering

A vigorous but far less invasive native wisteria from the eastern United States, producing dense, fragrant, lilac-purple flower racemes up to 15 cm long in late spring to early summer. More restrained and better-mannered than Asian species; suitable for smaller gardens. Hardy to USDA zone 5. Thrives in full sun with moist, well-drained soil and benefits from twice-yearly pruning.

Plant type: flowering

Watch for — Failure to flower: The most common complaint. Causes include insufficient sun (needs 6+ hours), overly rich or high-nitrogen soil, root disturbance, or youth (grafted plants may take 2–3 years; seed-grown 10+). Root pruning (driving a spade 30 cm into soil in a ring around the base) can stress-trigger flowering.

The reasons american wisteria isn't blooming

Almost every non-blooming american 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 american 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 american wisteria to flower

Maximise sun. Give american 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 american wisteria and get the feeding right with the american 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

American 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 american wisteria care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

American wisteria blooming — frequently asked questions

Why won't my american wisteria flower?

American 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 american wisteria bloom?

Give american 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 american wisteria normally bloom?