READER’S QUESTION

WE HAVE a yellow Banksia rose in full flower on our house wall. We love the plant, but it’s out of control. When is the best time to prune it? T. Ellis, Canterbury. THE creamy yellow, button flowers of Rosa

banksiae Lutea come in profusion — but only in spring. Its growth rate is astonishingly fast, with ‘fishing-rod’ stems growing 20ft in a matter of weeks.

Prune as hard as you like, immediately after flowering. In particular, remove the older, many branched stems.

Spare as many of the young basal shoots as you need and tie those in for next year’s show.

In summer, further shoots will appear. Tie these to the support, too, after removing those you do not need.