John is here to answer your gardening questions
More globe thistles please!
Q Our globe thistle has spread with little babies attached. Can I divide it and, if so, how do I do it?
A By all means. Ideally, wait until late March or April when the soil is warmer and temperatures are more conducive to robust growth. Then carefully remove well-rooted offsets, as new plantlets are called.
Replant them 18in/45cm apart each way (or wherever you wish them to grow) in a sunny, well-drained patch of prepared soil. Ideally, enrich it with crumbly well-rotted garden compost or a proprietary brand of composted manure to encourage plants to excel.
Augment manure with 6oz/168g per sq m of fish, blood and bone meal worked into the soil surface. Repeat the latter monthly throughout the growing season. A statuesque member of the daisy family, Asteraceae, previously named Compositae, the globe thistle (Echinops ritro) is an invaluable addition to a border. Its blooms attract bees and many other nectar and pollen-seeking insects. It’s also very drought tolerant.
Can I grow raspberries together?
QI want to plant raspberry canes in a long, large container. Will this work and can I grow early and late varieties together?
AProvided the container is about 12in/30cm wide and deep, with 1/2in/13mm drainage holes at 6in/15cm intervals, and is supported on bricks so that surplus water can freely seep away, and you fill it with peat-free potting compost, your canes should prosper.
We suggest that you opt for summerfruiting varieties, such as ‘Malling Jewel’, ‘Malling Admiral’, ‘Malling Minerva’, ‘Glen Ample’ and ‘Tulameen’ which, together, will crop from June to early August.
All are pruned after picking by cutting back fruited canes to near the base and tying in new growth to crop the following year.
Clematis trim
Q I need to prune an overgrown Clematis ‘Jackmanii’, but how should I do it?
ALike all viticella varieties, which flower from mid-summer to autumn, the best time to prune it is in early March. Choose a mild spell when frosts are not expected and shorten all shoots to about 6in/15cm of the base. Use sharp secateurs to cut just above a pair of buds. Remove completely any immature and undeveloped stems whose buds have died.
Follow pruning by feeding with a balanced granular fertiliser in April and water it in if the soil is dry.
Is my sweet box toxic to dogs?
Q I have several Sarcococca hookeriana shrubs, but I am worried that its black berries are poisonous to dogs. Our hound is very good at digging and pruning, so would she be safe around a sweet box?
A
