Plant Doctor Archive

Unhealthy roses

I AM new to gardening. We recently bought our first home and have inherited some old rose bushes. They appear to have black spot. What should I be doing at this time of the year to tidy the plants up and get them looking healthy again for spring? Can I prune them now?

ROSES can be a real joy, but do need some work. You shouldn't get too much Black Spot in New Plymouth, as it is not as humid as other regions. However, to combat it you can use Yates Shield or Super Shield. Alternate with other fungicides like Bravo. You can do a light prune now to get the plants under control. Prune about one third off at once, or as you pick flowers. Take out any dead or badly diseased wood, and prune good shoots back to an outward pointing bud. Throughout the winter use a winter spray programme of Yates Champion Copper and Conqueror Oil until the spring growth shows. Some very old rose bushes can be encouraged to put out growth if you scrape off some of the old bark at the base with a wire brush.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.