Wisteria has a special place in my list of favourite plants. A large, mature wisteria in full flower is really something to behold. I don’t know where my fascination for wisteria comes from, maybe it’s the magic of seeing seemingly dead wood suddenly sprout long, pendulous racemes of heavily scented flowers, before any leaves have appeared; a veritable waterfall of flowers.
There can be some mystery surrounding planting wisteria and pruning it for maximum flowering. As the wisteria we have is still young, I am still learning as I go along.
First Year (2009)
I bought a wisteria soon after I started gardening. Since wisteria needs to bake on a south-facing wall, there was only one place it could go – beneath the kitchen window in the extension.
Being in Cambridge and seeing wisteria that has been growing on the face of colleges and buildings for many tens of years, seeing how thick the trunks can get and how high it can climb, a wooden trellis is all but useless for these plants. They need heavy-duty support so we put metal eye hooks into the wall and used thick galvanised wire. Wisteria will only get heavier and heavier as it grows and the worst thing is to have its support fall from a wall under its own weight after many years.
Our wisteria was planted around April/May in the prepared border. Once it was in, all we had to do was to occasionally wrap the running shoots around the wire and ensure it was well watered to get it established quickly.
I didn’t know it at the time, but wisteria sold at garden centres will be grafted onto a rootstock. This is so that the wisteria flowers after a couple of years. You can grow wisteria from seed or buy seedlings that are a few years old but be prepared to wait up to 20 years before it will mature and flower.
Grafted wisteria can have its own problems too. The graft can fail, either spontaneously by itself or through disease setting in at the graft. Look closely at young wisteria and you should be able to see where it has been grafted (you’ll see a diagonal scar line at the join). If you’re planting wisteria, keep the graft above the soil (easy unless you bury the plant) and don’t damage it; support it well otherwise the graft could weaken and split with the movement of the plant in wind.
On my wisteria I have noticed new side shoots emerging from the main trunk below the graft level. These should be removed as these shoots are from the rootstock and is not the growth you want – you shouldn’t encourage these to grow otherwise the rootstock will end up outgrowing and replacing the wisteria that was grafted onto it.
Second Year (2010)
Having just planted the wisteria the previous year I wasn’t holding out hope of it flowering after just one year but it did produce two small flower racemes in the spring. They were close together in the place where it gets the sun for longest (not a co-incidence). You can see from the leaves that this spot is in the upper left corner where the white drain pipe runs down to the ground.
By August the wisteria had managed to go around the kitchen window. It was still looking a little threadbare along its length but this is because all the growth is concentrated at the tip of the leading shoots.
When training wisteria, keep the leading shoots growing until they reach the end of the support and when they have gone as far as you want them to, then cut off the tips. This will encourage the wisteria to bush out. It will still be a few years before our wisteria will reach the end of its support so we’re still keeping the runners growing.
Third Year (2011)
The wisteria produced several more flowers this spring but it is still a very young plant as wisterias go. We counted about 15 flower racemes and it will still be a few years before there will be too many to count.
With the recent two harsh winters the, leading shoots have died back to older wood but new side shoots have emerged close to the ends that has allowed us to continue training the wisteria along the wire.
Fourth Year (2012)
This is the year the wisteria went “floribundant”. I was absolutely over the moon to see the profusion of flowers right along the whole length of the vine. The flowers opened in a wave starting with those closest to the base and spreading right to the end of the runners. The whole show lasted the best part of two months and what the picture can’t give you is the gorgeous scent that that seemed to just cascade off the flowers. If you’re stood where I took this picture, you don’t even need to sniff the air, you can smell it by just breathing. Absolutely wonderful.