Amethyst Falls American wisteria

Sun

Full sun gives the best flowering; tolerates partial shade but produces fewer flowers.

Water

Keep evenly moist while establishing. Once established, water deeply during prolonged dry spells, especially beside walls or in containers.

Soil

Moderately fertile, moist but well-drained soil; tolerates clay if it does not remain waterlogged. Strongly alkaline soil can cause yellowing leaves.

Height

10-20 ft (3-6 m), depending on support and pruning

Spread

4-6 ft (1.2-1.8 m) when trained; can spread farther if left unmanaged

Flowers

Dense, hanging clusters of lavender-purple flowers in late spring to early summer, sometimes followed by lighter repeat flowering in summer.

Foliage

Green, pinnate leaves made up of oval leaflets; leaves fall in autumn.

Growth

Moderate; slower and less vigorous than Asian wisterias

Care needed

Medium

• Pollinators
• Deer resistant
• Heat tolerant
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   2 ft (0.6 m)

2. After 1 year

   3 ft (0.9 m)

3. After 2 years

   4 ft (1.2 m)

4. After 3 years

   5 ft (1.5 m)

5. After 5 years

   6 ft (1.8 m)

   full size

About 4 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Native to

the US

Growth rate

Moderate

• Provide a strong pergola, arbor or wall-mounted wire system before planting; keep stems away from gutters and roof spaces.
• Tie young shoots loosely to the support and select a few main stems to form the permanent framework.
• Water deeply through the first growing season and during extended dry periods thereafter.
• Apply a 2-3 in (5-8 cm) organic mulch in spring, keeping it clear of the main stem.
• Avoid high-nitrogen fertilizer, which encourages leafy growth at the expense of flowers.

Pruning. After the main flowering flush, shorten unwanted side shoots to keep the plant within its allotted space, leaving some new growth if you want repeat flowers. In late winter, remove dead, damaged or crossing stems and thin crowded growth without cutting back the permanent framework unnecessarily.

Late winter

Remove dead or crossing growth and check that supports and ties can accommodate thickening stems.

Spring

Plant when the soil is workable, water thoroughly and mulch around the root zone.

Late spring

Guide new shoots onto the support and check developing flower clusters for aphids.

Early summer

After the main flowers fade, shorten unwanted shoots and remove growth heading toward gutters or nearby trees.

Summer

Water during prolonged dry spells and tie in selected replacement shoots.

Autumn

Collect fallen seedpods where children or pets could reach them, and check the stability of the support.

• Train over a sturdy garden arch to frame a path with hanging spring flowers.
• Grow on wall-mounted wires beside a sunny patio, leaving space between the stems and the building.
• Cover a modest pergola where a less vigorous alternative to Asian wisteria is needed.
• Train as a narrow flowering backdrop behind catmint, hardy geraniums or ornamental alliums.

Garden styles it suits: Cottage garden, Romantic rose garden, Traditional, Southern, Modern courtyard and Pollinator garden.

Plant it with: Catmint, Hardy geranium, Ornamental allium, Salvia and Daylily.

Wildlife: Flowers attract bees. American wisteria also supports some native moth and butterfly caterpillars in its North American range.

• Few flowers: provide more sun, stop high-nitrogen feeding and avoid repeatedly removing all new shoots; recently planted vines may need time to establish.
• Yellow leaves with green veins: alkaline soil can restrict iron uptake; check soil pH and use an appropriate chelated iron treatment if needed.
• Aphids on young shoots: rinse off small colonies with water and encourage ladybirds and other predators.
• Root rot or dieback in wet ground: improve drainage and avoid planting in a site that stays saturated.

Toxic to people, cats, dogs and horses if eaten. All parts should be treated as poisonous, especially the seeds and pods; ingestion can cause abdominal pain, vomiting and diarrhea, sometimes severe. Seek medical or veterinary advice promptly after ingestion.

• Chinese wisteria (Wisteria sinensis)

  Usually flowers before or as the leaves emerge, has longer flower clusters and produces velvety seedpods; American wisteria flowers after leafing out and has smooth pods.

• Japanese wisteria (Wisteria floribunda)

  Usually has much longer, looser flower clusters and more leaflets per leaf, although counts overlap; its seedpods are velvety rather than smooth.

Wisteria honors the American physician Caspar Wistar, while frutescens means becoming shrubby or woody.

Propagation. Propagate by layering a low shoot or taking softwood cuttings in early summer. Seed-grown plants will not reliably retain the characteristics of 'Amethyst Falls'.

Accepted botanical name

Wisteria frutescens

In the US and Canada

Native in the lower 48 states.

Native range

Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana and Maryland.

Measured

Soil pH 4 to 7. Average height 1524 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.