Category Archives: wisteria

Wisteria – Growing Tips & Maintenance

A pink Chinese wisteria covering a pergola in Bonny Doon

Wisteria season is winding down unless you have a repeat bloomer like a ‘ Cooke”s Purple’ or ‘Amethyst Falls’. I’ve heard it all: “Why doesn’t my wisteria bloom?” or “I planted a wisteria in the wrong place, how do I get rid of it?’ or “I love my wisteria but it’s taking over the porch ?” (insert garage, house, shed or other structure) Seems we either love ‘em or hate ‘em on our own property. Growing somewhere else they are always the stars of the spring garden. If any of this sounds familiar to you here are some tips on how to handle yours.

Wisteria are one of nature’s most resilient survivors. They are able to withstand and recover quickly from difficult conditions. To some they are a little too tough for their own good with a growth rate rivaling bamboo during the summer. If you dream of a wisteria-covered pergola shading your patio here are some maintenance tips that are sure to keep both gardener and vine happy.

A pink wisteria growing under a fragrant purple variety covers a gazebo.

Wisteria are so vigorous they can be pruned at any time, keeping them in bounds and clearing out unwanted or dead growth. Prune out any stems you see extending into eaves, windows or shingles. If yours has gotten away from you, you can even prune it down to the ground and start over with training although you’ll have to wait a few years for your vine to bloom again.

To their control size major pruning is done during the dormant season. Start by trimming the long tendrils that grew over the summer back to about 6 inches from the main trunk. Cutting the tendrils back in this way will initiate flower bud development, neaten the plant up, and show off the attractive trusty, gnarly character of the vines.

Whatever time you do renovation pruning remember the response of the wisteria to aggressive pruning is to literally explode with new runners. They put energy into new vegetative growth at the expense of flowering. Make sure you keep up on ongoing maintenance pruning by removing all unwanted runners right to their point of origin. Then prune back the others to 3 buds or sets of leaves. Repeated pruning of these runners is what will eventually give you spurs of wood, short laterals that in turn will provide you with flower clusters. You need to prune these runners all season long which ends up being every 3-4 weeks.

Do not fertilize your wisteria. They do not flower well if there is an over abundance of luxuriant growth. Over feeding also ends up giving them the means to become unmanageable monster. If you have trouble getting your vine to flower an application of a high phosphorus fertilizer may promote blooming.

A diligently pruned wisteria at Filoli Garden

Maintaining a wisteria requires some diligence but the reward is worth the effort. Remember this especially during winter pruning season to make summer maintenance easier. If you find that the wisteria vine has invaded a nearby bed, cut roots with a shovel below the soil line to control any that have wandered.

Which variety of wisteria should you get to cover your arbor, pergola, tree or other structure?

A Cooke’s Purple wisteria growing on a pergola in Boulder Creek.

Chinese varieties such at ‘Cooke’s Special’ have clusters of fragrant blue-purple flowers 20 inches long. This variety can re-bloom which makes it a favorite. Chinese wisteria can take up to 20 years to mature enough to produce flowers, but once it has matured, the plant is very long lived and can live up to 100 years.

Japanese wisteria like ‘Caroline’ bloom early with mauve flowers. ‘Royal Purple’. known also as ‘Black Dragon’ , has sweetly scented dark purple flowers. Japanese wisteria are most effective when grown on pergolas so their long flower cluster can hang freely.

American wisteria, native to more eastern areas of the U.S. is a smaller, less invasive species that grows ar about a third the rate of Asian wisteria. ‘Amethyst Falls’ blooms at an early age with lightly fragrant purple racemes. Use in containers for porch or patio, train up an arbor or trellis or as a small free-standing tree.

Silky varieties produce a profusion of short, 6 inch, fat clusters of strongly scented flowers that open all at once. They have velvety seed pods and bloom best in full sun.

All parts of the wisteria vine contain a toxin known as wisterin which can cause stomach upset. Growers should also be wary of pets and children eating the flowers or seed pods.

Making the Most of your Garden

Early summer is the right time for many garden activities that you don’t want to leave to chance. Keep these reminders in the back of your mind to tackle when the mood hits you.

Pink wisteria in bloom before summer pruning

Look for any pest problems so you can do something about them before they get out of hand. I’m OK with a few holes here and there but a heavy infestation should be trimmed off or sprayed with an organic insecticide.I inspect the tips of my fuchsias regularly for fuchsia mites and clip off any distorted growth. I hate to spray even organics on fuchsias due to the hummingbird activity. Lately I’ve seen rose slugs making lace out of the leaves so I crush by hand or spray with organic BT. Walk around your garden with a beverage in hand to spot problems on a regular basis.

Many plants, both vegetable and ornamental, are bothered by aphids and other sucking insects as well as foliage and flower eating bugs. From cucumber beetles, flea beetles, stink bugs, weevils, curculios to borers , the list of trouble makers is endless.

To help deter them mix up some pepper spray in your kitchen.

  • 1 tablespoon hot pepper sauce or 1 teaspoon cayenne pepper
  • 6 cloves garlic, crushed
  • 1 quart warm tap water

Let stand I hour, strain and spray plants either in the morning or evening.

If you battle dandelions and don’t want to use chemical weed killers around pets and children, get out the white vinegar from the cupboard. On a hot sunny day spray straight white vinegar directly on the weed. This method will kill whatever it touches so direct the spray carefully. If the dandelion is in the lawn, wait a week, pour some water on the dead spot to dilute any lasting effects of the vinegar. Then poke some holes and drop in grass seed. Sprinkle a bit of fertilizer where the seed is planted and keep the area moist. In three weeks you won’t remember where the dead spot was and the dandelion will be long gone.

Another garden to-do this month includes summer pruning of wisteria. To increase flowering next spring and keep these vines under control cut new growth back to within 6″ of the main branch. If you want to extend the height or length of the vine, select some of the new streamer-like stems and tie them to a support in the direction you wish to train the plant.

Twist off spent rhododendron flower trusses

While I have the pruners out I’ll be shearing back early flowering perennials to encourage another round of blooms. The season has just started and you’ll be enjoying lots more flowers in the months to come if you deadhead regularly. Perennials and shrubs that benefit from trimming an inch or two below the spent blooms are erysimum, lavender and Pink breath of heaven which will keep them compact.

Twist off spent rhododendron flower trusses and fertilize them.

Apply the second fertilizer application for the year to your citrus and fruit trees. The last one should be immediately after harvest. Apply the fertilizer to the soil around the drip line of the tree where feeder roots are located and scratch into the surface. Water in well. As with all fertilizers, make sure the trees are moist before you fertilize. Young trees in their first, second or third growing season should receive half the rate of established trees.

How to Live in Peace with a Wisteria

A wisteria is one of those plants that you either love or dread. One of nature’s most resilient survivors they are able to withstand and recover quickly from difficult conditions. To some they are a little too tough for their own good with a growth rate rivaling bamboo during the summer. If you dream of a wisteria-covered pergola shading your patio here are some maintenance tips that are sure to keep both gardener and vine happy.

Wisteria at Filoli Gardens in Woodside

Wisteria are so vigorous they can be pruned at any time, keeping them in bounds and to clear out unwanted or dead growth. Prune out any stems you see extending into eaves, windows or shingles. If yours has gotten away from you, you can even prune it down to the ground and start over with training although you’ll have to wait a few years for your vine to bloom again.

To their control size major pruning is done during the dormant season. Start by trimming the long tendrils that grew over the summer back to about 6 inches from the main trunk. Cutting the tendrils back in this way will initiate flower bud development, neaten the plant up, and show off the attractive trusty, gnarly character of the vines.

Pruning during the dormant season will also give you a fighting chance of keep your wisteria from getting into mischief. As you know if you have a wisteria, those long tendrils are capable of growing another 25 feet during the summer.

Wisteria shading a patio

Whatever time you do renovation pruning remember the response of the wisteria to aggressive pruning is to literally explode with new runners. They put energy into new vegetative growth at the expense of flowering. Make sure you keep up on ongoing maintenance pruning by removing all unwanted runners right to their point of origin. Then prune back the others to 3 buds or sets of leaves. Repeated pruning of these runners is what will eventually give you spurs of wood, short laterals that in turn will provide you with flower clusters. You need to prune these runners all season long which ends up being every 3-4 weeks.

Do not fertilize your wisteria. They do not flower well is there is an over abundance or luxuriant growth. Over feeding also ends up giving them the means to become un unmanageable monster. If you find the wisteria vine has invaded a nearby bed, cut roots with a shovel below the soil line to control any that have wandered.

Maintaining a wisteria requires some diligence but the reward is worth the effort. Remember this especially during winter pruning season to make summer maintenance easier.

Cooke’s Purple wisteria

Which variety of wisteria should you get to cover your arbor, pergola, tree or other structure?

Chinese varieties such at ‘Cooke’s Special’ has clusters of fragrant blue-purple flowers 20 inches long. This variety can re-bloom which makes it a favorite.

Japanese wisteria ‘Caroline’ blooms early with mauve flowers. ‘Royal Purple’ (also known as ‘Black Dragon’) has sweetly scented dark purple flowers. Japanese wisteria are most effective when grown on pergolas so the long flower cluster can hang freely.

Silky varieties produce a profusion of short, 6 inch, fat clusters of strongly scented flowers that open all at once. They have velvety seed pods and bloom best in full sun.