John is here to answer your gardening questions
Should I lift my dahlias?
Q I never know whether I should lift my dahlias or leave them in the ground. My soil usually drains well but we do get heavy frosts here. What is the best advice?
A If you can be sure that puddles don’t linger long after heavy rain, which indicates that drainage is good and your dahlia roots won’t be waterlogged, leave your plants in situ. Do though protect tubers from penetrating frost by mulching stem bases with straw or composted manure.
If, however, water is seen lying on the surface for a day or more after a drenching rain, lift your plants and store them in a cool but frost- free place, such as a garden shed or garage.
Ideally, before lifting them, shorten stems to around 9in/23 cm and label them. If you can’t guarantee frost-free storage conditions, nestle plants into pots or boxes of potting compost that comfortably accommodate the root system… and pack newspaper, wood wool or chipped bark between your charges to protect them from low temperatures.
Cutting back a curry plant
Q My Helichrysum italicum curry plant has grown very large. It’s fabulous, but should I cut it back?
A A wonderfully aromatic sub-shrub from southern Europe, it is not fully hardy. By all means prune it to rejuvenate it, but not now when we are liable to have sub-zero temperatures and hard frost.
The best time to tackle pruning – shortening shoots to within 2-3in/5-7cm of older wood – is from late spring to early summer when frosts have finished. If strong shoots have formed and you wish to enjoy more of this plant, you could use prunings as cuttings.
Simply shorten them to 4in/10cm, removing any leaves which might be buried. Encourage rapid rooting by inserting shoots to half their length in proprietary cutting compost or an equal parts mix, by volume, of Perlite or grit and peat-free seed compost
Using old compost
Q Can I reuse growbag compost on the garden?
A You certainly can. Packed with organic goodness which decomposes into material that worms and the soil’s microfauna can ‘eat’ and convert into life-giving humus, it can be used to mulch border perennials and shrubs.
Alternatively, improve your lawn with it. After using a garden fork or proprietary aerator to make holes in the turf, shovel it over the lawn and work it in with wire or plastic-tined lawn rake.
We also recommend it for potting up overgrown perennials that have been divided and which need a temporary home before planting them where you wish them to flower.
Planting a rose
Q I have been given a rose in a pot. Is now a good time to plant it?
A Though
