There are many species but the two most popular are Wisteria sinensis and Wisteria floribunda. Wisteria sinensis grows in an anticlockwise direction and Wisteria floribunda clockwise.
Wisteria has incredibly strong and woody stems and in time the trunks can be as thick as small tree trunks – it’s not a plant for a delicate trellis. Wisteria also offer valuable autumn colour and attractive pea-like seed pods.
With stunning pendants of scented flowers in May or June, a mature plant can completely transform a property.
Where to plant wisteria
Wisteria is a strong plant that lives for many, many years. The ideal support is a solid wall with strong galvanised wires to guide the plant. Plants are almost impossible to move once settled, so make sure you can provide plants with the space and support they require. All of the cultivars require a position of full sun or semi-shade. A moist, well-drained soil is ideal.
The best time to plant is in spring or autumn. Before planting, improve the soil by digging in well-rotted organic matter. Ideally, plant wisteria against a wall and run galvanised wires across it in order to train the plant. Don’t try and grow plants up a pergola, unless it is very strong, as plants will twist and break weak structures. Plant at the same level as it was in the original pot and water in well. Train new growth along the galvanised wires. Wisteria can be grown in containers but they will never be as successful as those planted in the garden. Ideally, only plant in a container if the plant is being trained as a standard. Choose the largest container you can find and use a good tree and shrub compost. Water well and feed in spring.
Few gardeners propagate wisteria as the wait for flowers is too long. However, if you have the yearning, then take softwood cuttings in mid spring. Cut lengths of new stem of about 15cm long, removing from the parent plant above a leaf joint. Cut the material back to about 10cm, just below a leaf joint. Remove the lower leaves, leaving about four at the top of each cutting. Fill pots with cutting compost, level and firm the compost and then water. Insert the cuttings into the pots so the leaves don’t touch and cover with a clear plastic bag. Place the cuttings in a well-lit room and ensure they don’t dry out. When signs of growth are evident remove the bag and pot on.
Wisteria: problem solving
Why has my wisteria not flowered? is a frequently asked question. Plants take time to flower; expecting flowers before the plant is four years old may be unrealistic. Plants that are grown from seed can take up to 20 years to flower but these are rarely, if ever, sold. To encourage flowers prune twice a year (see below) and be a little patient. If there are late frosts, the flowers can be damaged. There is very little that can be done about this if plants are mature and too large to be covered with a fleece.
Caring for wisteria
In spring plants will benefit from a high potash feed to encourage flowers.
How and when to prune wisteria
Prune wisteria twice a year, in August and February. If you fail to prune plants won’t flower well and plants will become vast. For the first few years give your attention to training the plant into the support. This involves pruning very low branches out, training in strong side shoots and cutting back side shoots to five buds in early August. Throughout the life of the wisteria cut back any shoots that appear below the graft union right back to the main stem. When pruning wisteria in August, prune mature plants by cutting back the shoots of the current season’s growth to five leaves. The long wispy growth is very evident at this time and if not removed will become a nuisance. When pruning wisteria in February cut back the very same shoots but back to three buds. Mature plants are hard to kill, so don’t worry if you get it wrong.
Buying a wisteria
When buying a wisteria ensure that you buy a plant that has been raised by grafting. Buy one grown from seed and you will be waiting for up to 20 years for flowers. You can spot the grafted plants as they have a bulge at the base of the stem. Grafted plants can take up to five years to flower. Most nurseries only offer grafted plants.
Great wisteria varieties to grow
Wisteria sinensis – blue flowers in May or June before the foliage. Very fragrant. Reaches a height of 9m.
Wisteria floribunda‘Multijuga’ (pictured) – of all the wisterias this has the longest pendants of flowers. Lilac flowers that appear with the leaves in June. Reaches a height of 9m
Wisteria floribunda ‘Kuchi-beni’ – mauve-pink flowers in June with the foliage. Floribunda types are not as vigorous as others. Reaches 8m in height
Wisteria floribunda ‘Domino’ – suitable where space is limited. Blue flowers in May or June with the foliage. Reaches a height of 6m
Wisteria sinensis ‘Alba’ – white flowers, often before the foliage. Reaches a height of 9m