Let’s grow some Wisteria.
To begin with, this vine is found in two basic species in garden shops.
They are W. floribunda or Japanese Wisteria and W. sinensis or Chinese Wisteria
For gardeners south of zone 7, this plant – particularly W. floribunda – is a noxious weed able to strangle unsuspecting trees at a single bound.
Mind you, it is a pretty noxious weed but still it grows quite rampantly in the warmer parts of the continent.
Those of us in colder areas can only wish.
Hardiness of Wisteria
Wisteria floribunda is the most cold tolerant, growing up into USDA zone 4 (C5) and is differentiated easily from the more tender Wisteria sinensis(USDA 5/6) because it twines around branches clockwise while W. sinensis winds itself counter-clockwise.
I grew Wisteria floribunda at my USDA zone 4 nursery garden for about 6 years before a particularly vicious winter (lots of -40F days) killed it.
W. floribunda is deliciously sweetly scented (more so than W. sinensis) and once you have it blooming, you’ll never want to be without it.
You’ll be able to find attractive colours in both Wisteria species.
How To Grow
Think of these plants as woodland edge plants. They like a semi-shaded area with full afternoon sun or even full sun. They do not like shady areas and will seldom bloom there.
Want Best Soil
They do want the best soil you can give them.
Again, think woodland edge with lots of leaf mold, a good supply of moisture, deep soil and no clay to hold the winter wetness. Give this plant your best soil or make it your best. There is little point in trying to grow it on poor soil.
Don’t Use Much Nitrogen When Feeding
Use very little nitrogen. N promotes the excessive growth of leaves rather quickly with this plant and if you’ve been feeding with one of the liquid fertilizer products, you’ve been too nice to this plant.
Several shovels of compost in the spring should suffice but if you’re really concerned and need to feed something, you can add some rock phosphate or liquid fertilizer with a ratio something like 0-15-5 or 0-15-15.
As long as the first number is 0, the second number can be higher or equal to the third.
How To Propagate Wisteria
Note – treat wisteria seed as a perennial seed for germination.
Or you can take tender tip cuttings.
You’ll get better plants if you pick named varieties rather than seedling material.
The seedlings are cheaper but do plan on looking for one of the more interesting and intense colours.
Assuming this plant is in the garden and not in some wooded area, the objective is to get it to bloom and I can safely say it is all in the pruning. It is not about whether the wisteria is a named variety or seedling, it is all about how you treat the plant. If you let any wisteria grow willy-nilly and feed it, it will take its time getting top bloom because it is busy producing leaves.
It will bloom in this unpruned state when it is good and ready to do so and then it will bloom reliably year after year.
And fragrant too!
But If You Want Faster Blooms -Prune Your Wisteria
Pruning is fairly straightforward. Identify the main leader.
- From the main leader, there will be offshoots or laterals. These laterals can either be pruned back hard to 3 or 4 main buds to keep the vine in check on a regularly sized trellis.
- Or, the laterals can be allowed to grow out for five or six feet before being tipped and stopped from growing.
These laterals will now throw shoots of their own in subsequent years.
In the larger version, it is the shoots produced by these laterals that are then pruned back hard to 3 or 4 buds. It is this hard pruning back that will produce flower buds on the growth and you’ll be able to quickly see the difference in the dormant wood between a small vine bud and a bigger flower bud.
Every year, you’ll have to prune back the shoots to 3 or 4 buds if you want to see flowers the next year.
If You Don’t Prune
But bottom line, if you don’t prune, Wisteria will take its own sweet time producing a flower. If you want fast flowers, you have to prune.
The good news about this plant is that it is really tough to kill by poor pruning. Winter might get it, a cold winter will “burn off” the flower buds but it will outgrow poor pruning. So go right to growing Wisteria.