GARDEN GURU

Q There is a small retaining wall around my patio.

What could I grow that would trail over the top and flower? Paul Adams

A Consider Rosmarinus officinalis ‘Prostratus Group’, a cracking trailing rosemary with 20in-long stems clothed with purple-blue flowers from midspring to early summer. Or go for Glandora prostrata ‘Heavenly Blue’, an evergreen shrub with creeping stems bearing azure flowers from May to August.

Q Our garden contains several evergreen grasses, including Carex buchananii. Do they need pruning? Linda Sweet

A Evergreen grasses are usually best left to their own devices. It’s good for them to have dead or damaged leaves removed, but don’t prune them back hard. At this time of the year, all I tend to do is put on a gardening glove and comb my hand through a clump to remove any loose material or detritus.

Q I have a small courtyard garden and would like to grow an apple tree. Are there any that would suit my space? James Bishop

A Apple trees are generally the most vigorous of fruit trees, but grafting techniques have created many slow-growing, well-behaved species. Look out for apple varieties grafted on to M27, M9 or M26 rootstocks, which are fine in 15in-wide pots. Another option would be a cordon (single-stem) apple tree set against a wall or fence.