How To Care For An Old Or Established Wisteria.
Caring for an older or established wisteria – As wisteria become old they also become more robust and able to withstand changes to growing conditions and short-term climate changes.
How to care for an older or established wisteria
Pruning – with an older wisteria pruning need to be carried out twice a year. Firstly in the winter months to maintain the framework of the plant and tie in new stems to help the wisteria spread and secondly in the summer after the wisteria has flowered remove the long water shoots the plant produces after flowering. These shoots are non-flowering and seem to twist in mid-air looking for places to cling onto and wrap around. Ideally, the second pruning should take place after any nesting birds have left the wisteria.
Feeding – often people overfeed wisteria which has the effect of causing non-flowering. A general feed once a year with Growmore or other basic fertilizer with be fine followed by a couple of liquid feed applications using a feed high in potash such as liquid tomato feed in the summer months.
Pest and diseases – Mature wisteria are not affected by too many diseases but a few are scale insect which in extreme cases can be treated with an insecticide such as Provado or an organic method, the GardenAdvice Team have been trying to feed the gardens Blue Tits in the wisteria and whilst the birds are using the wisteria as a food station they make short work of any aphid or scale insects attacking the wisteria.
Another disease is dieback and canker in older stems. Firstly with correct pruning, it should be possible to prune to encourage new stems to grow from the base of the plant to replace the older stems.
Other factors that can affect your wisteria – with a large extensive root system often larger than most other plants wisteria can be affected by changes in soil conditions especially changes to soil pH. Ideally, wisteria needs a soil pH slightly on the acid side and often the soil pH can be changed by building works which import lime into the soil with builders’ sand or other building materials So if you have or are having some building work carried out it’s worth carrying out a soil sample test after the work to check the soil pH