MRS Martha Macdonald has had the same garden for almost 40 years and can't recall having ever had much serious trouble with spring frosts - until three or four years ago.

First it hit the trees at what she calls the bottom end of her garden where the apples lost all of their blossom, and then her beloved magnolias failed to produce their usual display of spring bloom.

A neighbour said the garden was a frost pocket but how could this be the case when the garden had not been similarly troubled in the past? She didn't even really know what a frost pocket might be and, besides, the winters recently had been comparatively mild.

She wrote to me for some answers. I can only guess that if a frost pocket is to blame, the trouble might lie in that reference to the bottom end of her garden. It seems likely that the garden is on a slope and the problem might be further down the slope, perhaps in someone else's property.

Frost tends to roll downhill and if there is an obstruction, like a wall, a hedge, perhaps a house, the downward movement of cold air is halted and layers of frost build up. That's a frost pocket. If the obstruction is within someone else's property, of course, there may be little that can be done about it.

One way to minimise the problem is to screen vulnerable plants from early morning sunshine which causes much of the damage by quickening the thawing process and shrivelling the petals. You might, of course, put up a wall or a hedge on the upward side of the slope, preventing the cold air from rolling into the fruit trees and magnolias in the first place. The effect of this could be to cause a frost pocket on the other side. The neighbours on that side might not be pleased!

Jack and Joyce Blair are proud of their garden but feel that it is a bit drab during the winter. Mrs Blair thinks that a few small trees or shrubs with interesting bark might be the answer so she wrote to ask for some ideas. Trees grown for their unusual bark as much as for flowers, foliage, or overall shape, can add a lot to the appearance of a garden, especially in winter.

Birches and acers have very striking bark and one of the most distinctive members of the birch family is betula jaquemontia, which has pinky white bark.

Another, Grayswood Ghost, has the most startling white trunk. Betula lutea has bark which peels revealing all shades of orange and brown and the river birch (betula nigra) has a shaggy coat.

Among the acers or maples, acer griseum is well known as the paperbark maple because of its peeling mahogany-coloured bark. Acer groiseri hersil is another wonderful choice for its white marble bark and crimson autumn colours too.

There's a simple answer to the query that reached me this week from a young man who has just taken over a new garden. He asks what is the best vegetable crop to grow in an area where the ground has never been cultivated.

The answer, without doubt, is potatoes as they will clear the land of weeds, partly because of their dense cover and because their strong roots will break up the soil.

If the ground was previously grassland, you can expect some trouble from wireworm, which can be a serious nuisance in new gardens, especially in wet summers. Use a soil insecticide when you plant your tubers