How to Grow Wisteria

If you want your Wisteria to flower, start with buying a Wisteria plant in the spring in flower or with flower buds on it. That way you know it can flower. The image left shows a small newly planted Wisteria with some small flowers on it. This Wisteria was newly planted in 2007 and within 7 years had reached a height of 3.5m or around 12ft, and by 2018 had covered the entire wall space at the back of the house and is the Wisteria featured in the video above ' Wonderful Wisteria'. This is a testament to the vigorous nature of Wisteria and the need for longer (and longer) ladders to prune it. Hard to image this tiny plant grew to cover an entire wall of the house in 10 years.

 Wisteria is best purchased as a grafted plant. You are likely to have problems with any plant grown from seed, which may be cheaper, but it may take a very long time to flower, as in more than a decade. You can spot a grafted plant as there is a bulge in the stem just above soil level in the plant pot. If you view the video about summer pruning Wisteria at around 3min 40 sec you can see the base of the Wisteria and the graft bulge. 

When planting a new Wisteria, water it well and ensure that it does not dry out in the early stages. Once established, it will look after itself. Even in the drought of 2018 I did not water the wisteria and it was fine. Wisteria is fully hardy, although frost can damage the emerging flowers (racemes)(see below) which means a sheltered spot is best.  Wisteria can be grown as a standard if space is limited, which will involve careful pruning or select a smaller variety of Wisteria such as Domino’ or Wisteria brachybotrys.

Wisteria can be grown in a container but with varying degrees of success. Recently, a friend asked me for advice about growing a Wisteria in a container as the Wisteria had failed to flower. I suggested removing it from the container and replanting in a sunny spot, and the following spring it flowered beautifully. Given the problems getting Wisteria to flower, growing it in a container adds a layer of difficulty. 

 We often think Pruning Wisteria is tricky, but it's helpful to know that Wisteria is a very vigorous climbing plant and thankfully, difficult to kill by pruning. Equally, you are unlikely to stop it flowering, providing you prune at the right times, which are February for the Winter prune and July/August for the summer. The only risk when pruning a Wisteria is to cut into the hard woody main frame of the plant.

In the winter prune, you are shortening the spurs, and in the summer prune removing leafy growth; two different types of pruning. 

 In some ways, the winter prune is easier because you can see the framework of the Wisteria. Winter pruning is best done in February, on a mild day. In the winter prune you need to cut the shoots back to 3/4 buds reducing to 8/10 cms (3-4") Aim to leave the main plant framework in place and prune the shoots coming off the main frame work to encourage the formation of spurs.    

The summer pruning is just as essential, and it is best to prune hard. The purpose of the summer prune is to restrict and cut back the vigorous growth, so the plant will throw out new flower shoots in the spring. Viewing the main framework, and where you want the plant to grow, cut back and prune hard the long wippy (soft) growth to about 15cmc (6") Leave unpruned that which is needed for the framework. 

You may need to cut off a lot of the long wippy growth and also cut off all laterals which appear at the base of the plant. These are shoots being thrown out at the base and remove all.  

Thanks to Helen Yemm writing in her excellent gardening column, who remarked on the staining caused by Wisteria sap. It leaves brown marks on your clothes which nothing will shift. This makes it most important to be wearing your oldest gardening scruffs for this job. 

A final small point on the time and maintenance required by Wisteria. It drops a lot of leaves in November and December, see image left, which also takes some maintenance clearing them up.

If after trying everything, pruning twice a year for a year or so, watering and feeding it still will not flower consider abandoning it and buying another. Write it off to experience and when planting your new Wisteria, make sure it is in a sunny, sheltered spot. 

 One option if you want to grow Wisteria but do not fancy climbing up ladders to prune one solution is to train it as a standard.

It is best to start with a smaller, less vigorous variety of Wisteria. It is tempting to plant in a container, but Wisteria is more tricky to grow in a container and it is better planted in a suitably sunny spot. I have used this image because it shows the hoop framework which is used to support the Wisteria and create the shape. It is not essential to use a frame, but it helps to create support over which the Wisteria can climb and the flower plumes dangle down. Train one main stem upwards and then allow stems to spread over the framework, or fan out naturally.

Frost can occasionally cause problems. The Wisteria shown in the left image has been growing and flowering happily for 10 years with no problems. However, the Spring of 2017 had unusual weather, mostly it was drier than usual, and often warm, which advanced the growing season. The Wisteria was in full bud by mid-April when there was an unusually cold spell with both ground and air frosts in many parts of the country. The winegrowers in the south of England reported 75% damage to their crop after temperatures dropped to -5.

Frost doesn't do Wisteria any good either, as the image left shows. Some buds went on to flower, but as illustrated in the image, other buds were damaged and did not flower.  Wisteria is tough and it came the back next year. You can minimise frost damage by planting Wisteria in a sheltered spot.