UK gardening help and assistance


from Tom Cole's Monthly Gardening Corner

August 2000

Wisteria

One of the most common questions asker of me when at college is, 'Why does my Wisteria not flower?' - all it seems to do is send out loads and loads of lush green shoots, but not a single flower?' Many reasons can be attributed to lack of flowers, but the most common reason is probably due to quality of plant at propagation. Wisteria are grafted; that is to say two plants are physically joined together in order that the rootstock controls height and spread of the plant and also potentially bringing the plant into flower much earlier than it would on it's own rootstock. In fact the majority of the plants that are purchased from the garden centres have gone through a process of grafting - for more information why not send for the Fact Sheet on Grafting.

Another reason why Wisteria may be reluctant to sprout flowers could have something to do with the fact 'we', as gardeners, do not prune the plant correctly; a great deal of growers and eminent gardeners feel this to be true.

Always, when pruning any plant, remember the 3 golden rules of pruning:

  • Those plants that flower before July should not be pruned until flowering has finished (they flower on previous years wood),
  • Those plants that flower after June/ July flower on current seasons growth and should be pruned hard at the beginning of the year,
  • Notice where the flowers arise from; one year, two year or more, and then adapt your pruning techniques accordingly.

Follow this Step-by-Step guide to Wisteria pruning:

  • Restrict the growth of vigorous, leafy shoots to encourage more new buds for next year,
  • Cut back all long shoots produced this year, leaving 4-6 leaves. It is often advisable to cut well clear of the last bud, since these buds are easily damaged,
  • With over vigorous varieties, often this form of pruning can be repeated once every 2 weeks from late July through until late August.
  • Don't forget to feed the plant at he beginning of the year with a general purpose fertilizer such as Growmore, Osmocote or Fish, Blood and Bone at a typical rate of 50g/ m�
  • And who knows, next year there may be a bloom or two hanging tantalizing on your prized Wisteria. If the plant is within 5 years of age, allow for 1-2 more years of growing in order that a framework is established which could support flowers - good luck!
The information on this page was originally published on the web however, it was defunct at December 2008.