Anna Pavord: Weekend Work

What to do

The Christmas rose (Helleborus niger) is not tender, but the white flowers are easily spoiled by rain splashing mud on to the petals. Either cut the flowers and bring them inside or cover the plant with a cloche.

Tender herbaceous perennials can be protected from frost with humps of chicken wire, stuffed with dry leaves, straw or bracken. Tender wall shrubs and climbers may need the same.

Continue to prune bush and standard roses. Standards should not be pruned too severely, or else the bush will produce over-vigorous shoots which will spoil the shape of the head. Remove dead or diseased wood first, then cut back the growth made this season as much as is necessary to maintain a well-balanced head.

December is an excellent month to plant trees, as long as you don't choose a day when the ground is frozen hard. In town gardens, you need to think about the eventual spread of a tree's branches. The ornamental pear, Pyrus calleryana 'Chanticleer' can get tall (15m) but has a narrow outline (it's rarely more than 6m across).

What to buy

At this time the shelves fill up with books destined for the loo, if not the dustbin. But there are certainly some laughs in Sacha Langton-Gilks's book, Red Undies and Dutchman's Trousers (Collins £8.99). The undies are actually a begonia, which appears in the author's list of naughty plants, followed by plants for a WAG's border and plants to give to people you hate. She also includes plants for a religious border - the famous dahlia bishop of course, but also a magnolia called 'Holy Grail'. Sadly there's no border for atheists.