How Often Does Wisteria Bloom? A Guide to This Gorgeous Flowering Vine

Wisteria is one of the most stunning flowering vines you can grow. When it erupts into bloom in springtime, cascading flowers in shades of purple, pink, blue, or white create a spectacular floral display. However, many gardeners get frustrated when their wisteria refuses to bloom or only blooms sparsely. Understanding wisteria’s blooming habits is key to getting the most out of this vine.

When to Expect Wisteria Blooms

Wisteria is a woody, deciduous vine that only blooms on new growth. This means it forms flower buds during the previous growing season for the next year’s bloom. So you need to have a basic understanding of when wisteria blooms naturally based on the species:

• Japanese wisteria (Wisteria floribunda) blooms in spring before the leaves emerge, usually in April.
• Chinese wisteria (Wisteria sinensis) also blooms in spring before leaves form, typically April to May.
• American wisteria (Wisteria frutescens) blooms later in early to mid summer, usually June to August.
• Kentucky wisteria (Wisteria macrostachya) hits peak bloom in early to mid summer as well, around June to July.

Within these general time frames bloom time can vary by cultivar and your specific climate. For example, the cultivar ‘Amethyst Falls’ may start blooming as much as a month earlier than the straight species. Tracking your individual plant’s habits will give you the most accurate sense of when to expect flowers.

Bloom Frequency

• Most wisteria varieties bloom just once a year on growth from the previous season. However, some cultivars of American and Kentucky wisteria are repeat bloomers, with a second flush of flowers in summer on new growth.

• The cultivars ‘Blue Moon’ and ‘Aunt Dee’ can bloom up to three times in a single growing season if pruned correctly.

• Young wisteria vines typically take 2-3 years after planting before they begin blooming. However, starting wisteria from seed can take up to 15 years for the first blooms!

Why Wisteria Won’t Bloom

There are a few key reasons why an established wisteria vine may not bloom:

Insufficient Sunlight

• Wisteria needs full sun to promote flowering, at least 6 hours of direct sun per day. Too much shade will reduce blooms.

Immature Vine

• Patience is required with young vines. Don’t expect blooms until 2-3 years after planting.

Excess Fertilizer

• High nitrogen fertilizers stimulate leafy growth but inhibit flowering. Go easy on fertilizer to encourage more blooms.

Incorrect Pruning

• Wisteria needs pruning to stimulate flower buds. Improper pruning usually means too little pruning, but excessive pruning can also limit blooms.

Water Stress

• Drought conditions will cause wisteria to drop flower buds. Make sure vines get weekly deep watering for best bloom.

Age

• Very old, dense vines may bloom less even with good care. Thinning congested growth can help revive an aging plant.

How to Get Wisteria to Bloom More

Follow these tips to coax more flowers out of your wisteria:

Site in Full Sun

Wisteria thrives on sunshine. Aim for at least 6 hours of direct sun, the more the better. Morning sun is ideal.

Use a Support Structure

Give wisteria a strong trellis, pergola, or arbor to climb. This allows better air circulation and light penetration for improved blooming.

Water Weekly

Give wisteria a thorough, deep watering once per week in summer. More mature vines may need more frequent watering.

Plant in Well-Draining Soil

Wisteria prefers evenly moist but well-drained soil. Wet feet will cause root rot and poor flowering.

Avoid High Nitrogen Fertilizer

Go easy on fertilizer, which stimulates leafy growth at the expense of flowers. Opt for low nitrogen, high potassium formulas.

Prune Properly

Prune twice a year to maximize blooms – in summer to control rampant growth and again in winter to stimulate flower buds.

Allow Time to Mature

Have realistic expectations and be patient with young vines. Prune to shape the first 3 years while waiting for blooms.

Consider Repeat Blooming Cultivars

Select varieties known to bloom more than once like ‘Blue Moon’, ‘Aunt Dee’, or ‘Amethyst Falls’ for the longest flower display.

When and How to Prune Wisteria for More Flowers

Proper pruning is vital for keeping wisteria vines under control and encouraging prolific blooms. Follow this pruning schedule:

Summer Pruning

In early summer, after spring bloom finishes, prune back new shoots to 6 leaves or 6-12 inches long. This controls rampant growth while allowing some extension. Repeat throughout summer as needed to keep growth under control.

Winter Pruning

In late winter, prune summer shoots back to just two or three buds. Also thin congested vines by removing at least a third of the oldest, thickest stems at ground level. This stimulates new growth and flower buds.

First 3 Years

Prune only to shape the vine and direct growth the first three seasons. Allow vines time to mature before heavier pruning to maximize flowering.

Growing Tips for Success with Wisteria

Follow some basic growing guidelines to help your wisteria thrive:

• Plant in spring after the last frost once the ground warms up.
• Space vines at least 10-15 feet apart to prevent crowding and competition.
• Water newly planted vines regularly until established, then weekly during summer.
• Add trellises, pergolas, or other sturdy structures for wisteria to climb.
• Insert vine support posts at least 2 feet deep into the ground for stability.
• Fertilize lightly in spring with a low nitrogen, high phosphorus formula.
• Thin congested vines every few years to open up light and air flow.
• Prune frequently to control rampant growth and stimulate blooming.
• North and east facing walls provide ideal cool, sunny sites for wisteria.
• Consider planting wisteria in containers on patios and decks to control spread.

Gorgeous But Can Be Aggressive

One word of caution about wisteria – it can be a bit aggressive in the right growing conditions. Follow these tips to prevent problems:

• Carefully site vines at least 15-20 feet from structures, trees, and power lines.
• Monitor growth and prune frequently to keep rampant vines under control.
• Consider planting grafted, non-invasive wisteria cultivars like ‘Amethyst Falls’.
• Grow wisteria on a sturdy trellis or arbor so it doesn’t strangle trees and damage structures.
• Plant in containers or in spaces bounded by pavement to restrict spread of roots and runners.

Wisteria certainly earns its reputation as a high maintenance vine. But the glorious springtime cascade of flowers makes the effort worthwhile! Follow the tips in this guide to encourage your wisteria to Bloom as long and as profusely as possible.