How to grow Japanese Wisteria

The plant may not flower for a year or two, and it is important during this period to establish the formal framework.
As the plant grows it will send out many whip shoots, choose the sturdiest to tie into the vertical. If the plant has to cover a high structure, concentrate on establishing this before stretching out any laterals. Otherwise, tie in appropriately places shoots to the structure, and cut off at the main stem (or two buds) laterals that do not fit the plan. Don’t worry if the end of the chosen shoot shrivels up, just cut back to a good bud and wait for another to take over the leader. A good tip when tying in the shoots of ant plant to be trained is to leave the end 30cm free. This preserves the dominance od the apical but and growth should continue in this shoot. Pulling the lead shoot horizontal removes its dominance and side shoots are encouraged to grow. This is what you want if the plant has grown to cover the space allocated but more growing is required preserve the visor of the lead shoot
Continue to tie in the framework shoots and in addition prune twice a year. The first formal pruning is mid summer, cut back all whippy growth (apart from the shoots that form the framework) to 5 buds. This will tidy the plant up and encourage more laterals, sun on the wood will ripen it and promote flower buds. The second formal pruning takes place mid winter, when the leaves have been shed and the plant is dormant. The structure is easily seen, tie in the framework branches and prune every thing else back to two buds. This encourages the production of flowering spurs on the framework branches. The wisteria flowers from mature spurs. It is quite tricky to distinguish between flower buds and leaf buds, but generally flower buds are fatter and rounder, leaf buds being slimmer and more oval and pointed. But don’t worry about cutting of flower buds, if pruning is done at the correct time of year, it will only enhance the end effect

When pruning the plant twice a year, take a few minutes to inspect the graft union. Any shoots that appear below this graft will be the root stock and must be removed or the variety will not grow. To be safe remove all shoots from the main stem up to 30 cm from the ground. Make sure that the graft is sound and dry. It must not be covered with the earth as this will encourage suckers from the root stock and will make the union prone to rot. Grafts can fail at any time in the plant’s life, and it is a common cause of plant failure. Quite often a neglected wisteria is actually the root stock in bloom rather than the desired variety as inadvertent suckers have been allowed to take over.

An easier option is to let the plant grow up a sturdy host tree. No need to prune, just let it go!

Wisteria grow readily from seed but the seedlings may not grow true to the parent plant. The seedlings are used to provide rootstock on which is grafted a stem of the desired variety
Seedlings also take a long time to reach flowering age, may be seven years or so.

Wisteria prefer a sunny spot and will also need a sturdy support, even if it is to be trained as a standard. Wisteria can be trained onto wires against a wall or a sturdy trellis or over a pergola. Do not underestimate how heavy a vigorous wisteria can be. An easy option can be just to ‘let it go’ into a tree. If it is to be trained as a standard it will need a sturdy post, at least to start with.

Plant at least 1m from the wall base or tree trunk (angling it towards the support) to avoid the rain shadow. Dig the hole two or three times as wide as the pot it was grown in and a little deeper. Loosen the soil in the bottom of the hole and add some blood fish and bone. Check that the plant when in the hole, is not so deep that the graft is covered, it needs to sit above the ground level, with the graft well clear. Back fill, water and firm in. Take the wisteria off the stick it was grown on and attach it to the support, with string.
Water well during the first growing season

Wisteria can be cut for the vase but do not last well

Seeds as well as all plant parts are toxic
Seed pods resemble pea pods and ripen during the summer, often still attached to the plant at the winter prune.
Seeds do not come true to parent plants, and take many years to flower
Wisteria can be grafted onto rootstock or layered to produce new plants true to the parent. They will also flower sooner by this method

These estimates for how long Japanese wisteria takes to sprout, grow and harvest are from real observations from real gardeners, right around the world.

Wisteria can be an invasive species in south eastern USA

Wisteria

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