Shrub · Fabaceae
Wisteria
Wisteria sinensis
Give it full sun, a strong support, and two hard prunings a year, and wisteria will drape itself in flowers each spring.
Full sun
Every 5–10 days
1095–2555 days
USDA 5–9
Overview
Few climbers reward you quite like a wisteria in full bloom, when long racemes of blue-violet flowers hang in soft curtains over an arbor. It is a woody, twining member of the pea family, and the very vigor that makes the show so lush is the same vigor that keeps you on your toes. A grown vine has more in common with a small tree than with a dainty climber, and that is nothing to fear once you know it.
Two Asian species fill most gardens. Chinese wisteria twines counterclockwise and opens nearly all its flowers at once, while Japanese wisteria twines the other way and unrolls its racemes slowly from base to tip. Both are lovely but invasive across much of the eastern US, which is exactly why the gentler native American and Kentucky wisterias deserve a close look.
Wisteria really asks for two things, patience and a firm hand, and both are well within reach. A young plant may sulk for a few years before it flowers, and once it settles in it will happily climb trees and gutters if nobody stops it. Give it full sun, a sturdy support of its own, and a hard pruning twice a year, and it will thank you with decades of bloom.
Care
The short version: give wisteria full sun, a very strong support set well away from trees and the house, and lean soil with little or no feeding. Water it deeply while it settles in, then prune hard in both summer and winter to keep it in bounds and coax out the flowers.
Light
Wisteria flowers best in full sun, and a spot that catches direct light all day is what fills the vine with bloom. It will put up with partial shade, but shade is one of the main reasons a healthy-looking plant simply never flowers, so give it the sunniest place you can.
Water
Keep the soil moist but well drained while your plant is settling in, watering deeply whenever a dry spell sets in. Once it is established it handles drought fairly well, so let the top inch or so dry between waterings rather than keeping it wet.
Soil
Wisteria is easygoing about soil and takes clay, loam, or sand and either wet or dry ground in stride. Aim for moist, well-drained loam with a pH between 6.0 and 7.0 and it will happily do the rest.
Temperature
This is a tough, cold-hardy vine that copes with a wide swing, roughly -20°F to 100°F (-29°C to 38°C). The one weather worry is a late spring frost, which can nip the flower buds just before they open, so mind the forecast in early spring.
Humidity
Ordinary outdoor humidity suits wisteria just fine, so there is nothing to fuss over here. What counts far more is air and light reaching the vine, which simply means thinning its rampant growth now and then.
Feeding
Go very light, or skip feeding altogether and let the plant get on with it. Wisteria wants little, and too much nitrogen pushes out leaves instead of flowers, so reach only for a low-nitrogen feed in spring if you feed at all.
Pruning
Prune hard twice a year to keep the vine in check and encourage bloom, and it is more forgiving than it sounds. In summer cut the long whippy shoots back to five or six leaves, then in winter shorten those same shoots to two or three buds, trimming away anything girdling its support.
Repotting
Wisteria belongs in the ground rather than a pot, so it is not really repotted. On an established plant, root pruning can nudge a stubborn vine into flowering, and few or no blooms despite plenty of leafy growth is your cue that it might help.
Size & spacing
Give wisteria plenty of room, because it climbs 10 to 25 feet (3 to 7.5 m) tall and spreads anywhere from 4 to 30 feet (1.2 to 9 m) wide. Set it on its own strong support, well clear of trees, walls, and neighboring plants, and everyone will be happier for it.
When to plant
Wisteria is a long-lived woody vine, so the timing to think about is planting rather than a yearly sowing. Set new plants out in spring or fall, then let them take their time, because the flowers can be a few years coming and, once they do, they arrive in mid-to-late spring.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Mid-to-late spring (April-May)
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Most wisteria worries boil down to a plant that will not bloom or one that grows a little too well for its own good, and both are fixable. Read the symptom, look at the plant's age and where it sits, then step in before the vine gets ahead of you. The three issues below are the ones gardeners meet most.
Strong stems that can strangle trees and bend structures
It helps to know upfront that wisteria is a heavy woody twiner that can climb over 60 feet and quickly outgrow whatever you offer it. When it is left alone it winds tight around tree trunks and slowly chokes them, and its weight can bow or break trellises, gutters, and downspouts. You will save yourself trouble by giving it a sturdy dedicated arbor set well away from the house, pruning hard twice a year, and freeing anything it starts to climb that you did not mean it to.
Fix:
- Provide a very strong, sturdy dedicated support (heavy arbor or metal structure)
- Prune hard twice a year and cut away any stems twining around trees, gutters, or downspouts
- Remove the plant entirely if it is engulfing trees or buildings
Vines slipping into the woods and harming native trees
The Asian species are invasive across the eastern and southeastern US, and they spread by seed, by runners, and by stems that root wherever they touch the soil. Once they get loose they build dense thickets and shade out or drag down native trees. Cut escaped vines back to the root and keep after the resprouts, and where wild areas sit nearby, reach for native American wisteria instead so you can enjoy the flowers with an easy mind.
Fix:
- Cut vines close to the root and repeatedly remove resprouts through the season
- Apply an appropriate systemic herbicide to cut stems in spring or summer where permitted
- Replace with a native, non-invasive alternative such as American wisteria (Wisteria frutescens)
Plenty of leaves but no flowers yet
Try not to worry if your wisteria climbs beautifully but holds back its flowers, because the usual reason is simply that it is still too young. A seedling can need 3 to 7 years or more before those first racemes arrive. Heavy feeding, too much shade, or a late frost on the buds can delay things too, so gently move it into full sun, ease off the fertilizer, and prune twice a year to help it build the spurs that carry bloom.
Fix:
- Be patient and let the plant mature; grafted or already-blooming nursery plants flower sooner than seedlings
- Stop applying nitrogen fertilizer
- Move or train the vine into a full-sun position
- Prune correctly twice a year (summer and winter) to build flowering spurs
Toxicity
Every part of wisteria is toxic, and the velvety seed pods and bean-like seeds are the most dangerous of all. They hold a lectin called wisterin along with toxic glycosides, and because the pods look so much like edible beans they have poisoned children more than once. Keep the seeds and pods away from pets, livestock, and kids, and clear any fallen pods from the ground.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Moderate
If a cat gnaws on the pods or seeds, expect vomiting that can carry a little blood, followed by diarrhea, a droopy lack of energy, and dehydration. The seeds and pods are almost always the trigger, so those are the parts to keep out of reach.
Dogs Moderate
Dogs find the bean-like pods tempting and often regret it, with hard bouts of vomiting that may show blood, loose stools, drooling, and a flat, subdued mood. Keep an eye out for dehydration if the tummy trouble lingers.
Horses Moderate
A horse that eats any part tends to go off its feed and turn dull, with vomiting, diarrhea, and drooling. The toxin sits in the whole plant, not only the seeds, so no part is a safe nibble.
Rabbits Toxic
Wisterin and the plant's glycosides make every part unsafe for rabbits. Even a small taste can bring drooling, a sore belly, and runny droppings, so it is kindest to keep them away from it completely.
Livestock Toxic
Cattle, goats, and sheep that graze the leaves, pods, or seeds can end up with severe stomach upset, drooling, and dehydration. Fencing the plant well off from any pasture keeps them safe.
Birds Toxic
The seeds and pods are toxic to birds, and the pods look so much like the beans a bird would normally peck that mistakes happen. Watch for vomiting, weakness, and dehydration if any is swallowed.
People Caution
The velvety pods look like edible bean pods and have poisoned children who tried the seeds. Even a couple of seeds can bring on severe vomiting, belly pain, bloody diarrhea, drooling, and dehydration, so keep little ones well clear of them.
The pods resemble edible beans and have poisoned children; keep seeds and pods away from kids and pets.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Choosing a wisteria really comes down to the showy but invasive Asian species or the better-behaved natives, and either way you get those draping flowers. These four cover the plants you are most likely to find.
Wisteria sinensis (Chinese wisteria)
You can spot this one by its counterclockwise twining and its fragrant blue-violet to purple, pink, or white racemes 6 to 12 inches long, which open almost all at once before the leaves come, though it is invasive across the eastern US.
Wisteria floribunda 'Macrobotrys' (Japanese wisteria)
This one twines clockwise and hangs exceptionally long red-violet racemes, said to reach 2 to 4 feet, that open slowly from base to tip, and while it is happily cold hardy it is also invasive in the eastern US.
Wisteria frutescens 'Amethyst Falls' (American wisteria)
A gentle, far less aggressive native with tidy 4 to 6 inch lavender-purple racemes in May that form on new wood, which is why it often rewards you with flowers while still young.
Wisteria macrostachya 'Blue Moon' (Kentucky wisteria)
A very cold-hardy native whose silvery-blue racemes can rebloom through the season, a reassuring non-invasive choice for northern gardens.
How to propagate
You can raise more wisteria from a pegged stem, a summer cutting, or seed, though only the first two hand you a plant that flowers just like its parent.
LayeringEasy
Spring to summer · Several months to a year to root
Layering is the kindest and most dependable way to copy a wisteria you love. Gently peg a low, bendy stem down into the soil in spring or summer and be patient, since it can take several months to a full year to root. The young plant carries the exact flowering traits of its parent, so you know just what you are getting.
Stem cuttingsModerate
Summer (softwood/semi-ripe) · Several weeks to root
Softwood or semi-ripe cuttings taken from this season's growth in summer will root for you in a few weeks. This path also holds onto the cultivar, so the plant you raise blooms just like the one it came from.
SeedModerate
Spring · Many years to first bloom
Seed sprouts easily in spring, but it asks for real patience, since seedlings vary and often need 7 or more years to flower. The seeds are also toxic, so handle them with care and keep them away from children and pets.
Myths
Feeding wisteria plenty of fertilizer makes it bloom.
Piling on high-nitrogen fertilizer actually works against you, coaxing out leaves instead of flowers, and most wisteria blooms better when it is simply left unfed. Full sun, correct twice-yearly pruning, and a little maturity are what truly bring the flowers.
All wisterias are invasive, so none are worth planting.
Only the Asian species, W. sinensis and W. floribunda, run wild in the eastern US. Native American wisteria (W. frutescens) and Kentucky wisteria (W. macrostachya) are far better behaved, and they give you the same draping flowers without putting nearby woodland at risk.