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Last updated on January 22nd, 2020
Why is my Wisteria not flowering
Wisteria is a climbing plant that produce masses of long petulant, sweetly scented flowers, usually lilac-blue, blue or white in colour. They lend themselves to many a situation and look fantastic when grown in a prominent position in pots or in the ground.
Wisteria can be affected by a few problems including sudden die back and root rot. The most common and frustrating problem is that they can be known for not flowering as much as they are known for the spectacular scented flower.
Choose an ideal plant to reduce the risk poor flowering
The first thing to consider if you do not already have a Wisteria or plan to replace one, is that Wisteria usually take around 5 years to flower. A Wisteria that is grown from seed can take up to 20 years to flower, and as such you should choose a Wisteria that has either been grown from a cutting or is a graphed plant. Most garden centres and nurseries sell graphed plants which is perfect and most are a specific cultivar. Graphed plants as easy to spot as they have a large bulge where the plant has been graphed onto a root stock at the bottom of the main stem.
Reasons Wisteria don’t flower
There are a few reasons why wisteria don’t flower once planted so lets look into them. Firstly, if you have just planted your wisteria and it has been planted for less than two years then give it time. Wisteria take up to 5 years to flower as previously mentioned.
Wisteria need to be planted in full sun and if planted in shade this will cause poor flowering, if not no flowers at all. Choose a location where they get at least 5 or 6 hours of sun.
Wisteria can usually flower poorly if the soil is not suitable for them, incorrect levels of potassium in the soil is common and can be corrected by applying sulphate of potash in spring at the level recommended on the box. High levels of nitrogen can also cause a Wisteria not to flower, the reason for this is nitrogen promotes foliage growth in plants which can affect the plant from producing flowers as they put all their energy into promoting new leaves. One of the ways to combat this is to feed with a phosphate fertilizer which is used to promote flowers and not foliage growth.
The buds on Wisteria form in Summer of the previous year growth and as such can be affected by dry conditions that cause the buds to distort or fail. Keep an eye on the ground conditions during July to September whilst the buds are forming by watering the plant sparingly during dry conditions during those important months.
Pruning wisteria incorrectly can cause them not to flower
Wisteria pruned incorrectly can cause them not to flower, and it is important to know when to prune. Wisteria grow well if not pruned yearly but if pruned every year, twice a year, this will encourage more flowers and better plants.
Prune twice a year, once a couple of months after flowering has finished when new growth is shortened to about 5-6 leaves. This helps control the growth and help promote more flower buds rather than new growth. Prune again for a second time in mid-winter around January – February to shorten the same growth again. Prune back to 3 buds, this is done as the flowers are produced on new growth so if you cut in spring you will be cutting the flower buds off and there fore reducing the amount of flowers produced.
Reasons Wisteria is not flowering summary
- Dry conditions during July – September when buds are forming. Water regularly to keep soil moist
- Wisteria need full sun. Plant in a sunny location where plant gets 5-6 hours of sun if possible
- Feed in Autumn with sulphate of potash to combat high levels of potassium
- Prune twice a year correctly to promote more flowers. Do not prune in spring