“Now that all the other many-hued flowers have scattered without a trace, the dead white heads of the miscanthus remains alone in the fields until the end of winter. As it stands there so gracefully, not realising that it has entered its dotage, and bending its head as if in memory of past glories, it looks exactly like a very old person, and one cannot help feeling sorry for it.”
Sei Shonagon , The Pillow Book of Sei Shonagon (tenth century),
translated by Ivan Morris (1967)
Winter is the pruning time for many plants, but none more so than wisteria. The most common reason for their failure to flower in spring is savage pruning. Don’t cut them off at ground level because they flower from last year’s growth so you will be cutting off all the potential flower buds which form on the spurs. Think of them like an apple tree. Find the main stems which give the framework or shape to the plant. Shorten all the other whippy growths to between 3 or 4 leaf buds from the main stems. Thin out the ones at the base by cutting them back flush to the trunk. You don’t want the growths which sneak along at ground level because they will put down roots and your one plant can become many.
At the same time, deal to borer where you spot it. You will find the borer holes in the older wood. I tend to reach for the CRC or cooking oil to spray down the holes. It smothers them. Or you can use fly spray. None of these seem to harm the plant whereas the borer can ruin entire sections over time. It pays to keep replacement leaders coming through in case your main stems get too badly damaged.
Wisteria whips are very flexible when first cut and can be used for weaving in a similar way to basket willow.
Step by step instructions for pruning (with photos) here.
First published in the Waikato Times and reprinted here with their permission.