Some plants that just won't play ball. Joe Canon has been trying and repeatedly failing to propagate a friend's shrub from cuttings and wonders if there is a knack. The shrub is Bupleurum fruticosum - a shrub he has had no luck in finding in any of his local nurseries.

This is a subject close to my heart - I love this shrub, a slightly tender, greenish-flowered, leaden-leafed shrubby cow parsley relative. Cuttings are notoriously hard to get going, so I suggest Joe grovels around in his friend's garden looking for seedlings.

Young plants seem to resent disturbance, however, and should be dug up with a great chunk of soil so they don't even notice they have been moved. A final home in a warm, well-drained sheltered place (preferably against a building) is a must.

Catherine Bird asks if the anthracite ash from the many fires she has had this winter can be used on the garden. I understand not. It is of no value to plants and may even contain elements that are harmful to them.

Andrew Robinson asks how to use newspaper in the garden. Thickly laid, newspapers can be used as paths between beds on clay-soil allotments. Ripped and scrunched up a certain amount, they can be added to compost heaps, bins and wormeries.

And I find a thick stack of motoring supplements makes a satisfying seat when winkling plantains out of my lawn or wrestling with a pruning saw and the undercarriage of large shrubs.

Allan Kelly asks how he can remove ''green mould'' from his planted-up terracotta pots and stop it reappearing. Spores of various algae are both air and waterborne, so if growing conditions suit (airborne spores like damp shade and porous surfaces) there is not much you can do to eradicate a certain amount of ''greening'' in the garden, particularly over winter.

Allan could scrub his pots with Biotal Algae and Mould Cleaner, a plant-friendly product that will clean off and inhibit the growth of algae on all sorts of garden surfaces (biotal.co.uk) I actually rather like the green algae that takes the new ''edge'' off terracotta and stone, but each to his own.