PROBLEMS SOLVED
Why won’t camellias flower outside? Do I cut back pelargoniums? Read on
SHRUBS
A Popularbecause of its sweet perfume, ‘Zéphirine Drouhin’ is prone to disease and your rose is infected with blackspot. The new growth probably is or has been infested with greenfly, which have naturally been controlled by ladybirds, but the distorted growth remains. Don’t worry about the new growth this late in the season, but roses vulnerable to blackspot and rust should be controlled by spraying early in the season. Then, if aphids are seen, rub them off by hand.
Q Will boiler vent affect which shrub we can plant?
A Any shrub commonly grown as a wall shrub could be planted in this spot and shouldn’t be affected by the boiler vent, nor pose a structural problem. I assume there’s a least some shade here. Add some horizontal supports and you could train a winter jasmine or chaenomeles, which will cover the area well and provide colour in spring or winter. Both tolerate some shade.
Q When might pineapple guava produce flowers?
A Your pineapple guava (Acca or Feijoa sellowiana) is very ‘tight’ in its pot and is probably drying out too much between waterings. This plant likes full sun, warmth and good drainage, but would grow better if potted on into a larger pot. Keep it moist in winter and repot in spring, using John Innes No 3 compost. Also try pruning back some of the long stems because flowers are produced on the fresh regrowth.
Q Why do camellias only open in water?
A It’s strange that your camellias produce buds that open when cut and brought into the home, but refuse to open outdoors. Perhaps the plants are in a very exposed or cold site so the buds are frosted. It is also possible, though not likely, that the plants are dry in spring – especially if they are in pots or against a wall or in a raised bed. However, it really is still a bit of a mystery!
Q Do I need to cut back 15cm-tall red pelargonium cuttings before overwintering?
A Keep them frost free over winter, in a cool greenhouse, at about 5C or on a sunny windowsill. They should be quite dry. Wait until spring to cut them back, repot and start them into growth again.
BULBS
Q Which spring bulbs suit windowboxes?
A The light only comes from one side in a windowbox, so any bulbs are prone to ‘stretch’ to reach the light and will be taller and floppier than in the garden.
