Kim Wilde answers your gardening questions.
I have moss and plants growing in my stonework and pavings. How can I get rid of them in a way that is safe for animals?
Moss is a particular hazard in pavings, because it's slippery, and weeds can be unsightly. Bio Organic is a fatty acid-based organic product that comes ready to use, but it will be less effective than non-organic products such as Roundup. There are also some organic vinegar-based products around; I've not tried any, but they sound promising. We use a power jet hose, which does an excellent (though temporary) job of dislodging moss and weed, supplemented by a weed burner (rather like those chefs use on crme brle), which we had custom-made. You can buy small ones from garden centres for around 20, or mail order from CJ Industries, 01239 615300. A scorched box ball somewhat shook my husband's confidence early on, which prompted him to use it only at dusk, when he could see the flame! Alternatively, why not make a virtue out of growing plants in the crevices, with the added bonus that they will help nudge out the weeds. Erigeron karvinskianus is a pretty daisy that self-seeds happily in pavings. Another winner is tough-as-old-boots thyme, which is a pleasure to walk on, its aroma being released as it is crushed underfoot.
I have a 20-year-old rambling rose that has developed black spot. Apart from spraying it, what can I do?
This sounds like a rambler in need of a good overhaul. Some air movement among the over-crowded stems will improve things - strong plants are better able to resist disease. Take out old stems, plus any damaged or diseased wood, straight after flowering. Dispose of leaves as they fall this year, but don't put them on the compost heap: the airborne spores can survive the winter to re-infect. However, this is prevention rather than cure. The only way to get rid of black spot properly is to spray with a fungicide, such as Systhane, from the end of September, covering the stems and ground. If you don't treat black spot? Well, your rose won't die, but it will look a straggly mess.