IT'S an old clich, but the longer I work with plants, and the more I learn about them, the more I realise how much there is still to learn.

A good supply of textbooks are a must for every gardener - not just the glossy, coffee table type which can be useful for inspiration but don't often have detailed information - but the sort of reference books that can be used on a day-to-day basis by the working gardener.

Top of the list for the most used book in the Brockhole gardeners' tea room is the RHS Gardeners Encyclopaedia of Plants and Flowers which has proved invaluable for refreshing our memories on plant names and for identifying unfamiliar plants brought in by visitors.

At home I also use the RHS A-Z Encyclopaedia of Garden Plants which has more detail but is set out differently; it's not so easy to look up a plant that you don't know the name of!

Hillier's Manual of Trees and Shrubs and Bean's Trees and Shrubs Hardy in the British Isles are useful volumes, with good, detailed descriptions of woody plants but, alas, few pictures.

For help with propagating techniques and timings, I have the Nursery Stock Manual by Lamb, Kelly and Bowbrick, and Plant Propagation by Hartmann and Kester.

These are not exactly bedtime reading books, but are extremely valuable for plants that are proving tricky to propagate.

We also have several practical books on growing herbs, fruit and vegetables, including two published by the RHS that I have had since I was a student (these have since been revised and reprinted).

Collins' Guide to Pests, Diseases and Disorders of Garden Plants helps us to identify and treat most of the plant illnesses that we come across, while the Forestry Commission and the DETR have produced a book called The Diagnosis of Ill Health in Trees.

This is fascinating, but rather like having a home doctor's book - we keep thinking our trees have all sorts of rare fungi and rots when they are really quite healthy.

Since gardening is about the whole environment and not only plants, to help with the identification of non-plant life in the gardens, we have copies of Collins' Guides for Butterflies and Moths, Wildflowers, Mushrooms and Toadstools, Birds and Insects.

And since gardening can also be about eating, I have recently invested in a copy of Christopher Lloyd's newest publication Gardener Cook which combines cultivation techniques with culinary tips and mouth-watering recipes.

Jobs for the gardener this week

l Give tools a treat, give them a thorough cleaning and oil any metal surfaces to discourage rusting.

They will be a pleasure to use next time the weather is fit for working outside.

l Make an early sowing of sweet peas if you have a cool greenhouse or bright windowsill to grow the plants on.

l Check the ties on climbers and wall plants; replace any that have come loose in high winds.