Gardening: How do you grow a Pitmaston Pineapple?

This most British of apples, like many others, is actually two trees in one: its performance depends on the rootstock.

MABBOT'S PERMAIN, Pitmaston Pineapple, Gloucester Cross: and there are plenty more names of apples to tickle the fancy among the 2,300 different varieties growing in the national collection at Brogdale in Kent.

Spanning centuries and continents - and a cast of enigmatic characters - the names alone are almost enough to persuade you to grow the apples, but their allure does not end there. Between them they offer a cornucopia of flavour, colour, size and shape that will bewilder anyone who has not got beyond Golden Delicious, Bramley or Granny Smith. It is not that these are bad apples, just an undistinguished tip to a gastronomic iceberg.

It is pleasing to see supermarkets beginning to extend their apple horizons a little, but if you want to make the most of the munificence of Malus domestica then you really want to be growing your own.

Apples are tolerant and adaptable, although their international dominion is only made possible by careful selection of varieties to suit local conditions. Avoid early flowerers if your garden is prone to late frosts, and any that are martyrs to canker if you have a heavy, wet soil. To set good crops, most apples require cross pollination from another variety in flower at the same time.

You may not realise it, but any apple tree you buy, (and indeed plum, pear or cherry) is actually two half trees joined together by a graft, usually made just above soil level. The above-ground section, or scion, is the named variety itself which determines the fruit that the tree will bear, while the rooted lower half, the rootstock, is from another tree entirely, grown specifically for the purpose.

Grafting like this has been practised for centuries, and the benefits are considerable. Most apples if grown on their own roots will produce an extremely large tree that is slow to bear fruit. By grafting on to roots that have a stunting effect on growth, this excessive vigour can be curtailed. The resulting compact growth makes pruning and picking easier, fruit is produced earlier in the tree's life and, most significantly for the gardener, you do not need acres of space.

Even growing on identical rootstocks, some apples like the Bramley are naturally more vigorous than others such as the splendid Egremont Russet. However, the most significant factor governing how vigorously any individual apple tree grows is not the variety, but the rootstock it is grafted on to. It follows that to make a good choice for any particular situation you need to know what this is.

In Britain you are likely to encounter six different rootstocks. They are, in ascending order of vigour: M27; M9; M26; MM106; and M25. Assuming average growing conditions they will produce trees to approximate heights of 1.5m, 2m, 2.5m, 4m, 5m and 6m respectively.

M27 will first begin to fruit in its second or third year after planting, whereas with an M25 you may be waiting 10 years for a first bite. MM106 is the most widely used, and for good reason. Even under less than ideal conditions it will produce a strong, healthy tree which is unlikely to outgrow its welcome.

If you are after apples to suit "step-overs", pot culture or small cordons, then M27 or M9 are likely to be the most appropriate. Be warned, however, that these very dwarf forms will struggle to establish if given poor soils or competition from surrounding grass, and will always require staking. For less restricted forms such as a fan, espalier or a small bush, M26 is likely to be the best bet.

At the top end, should you be planning a traditional orchard with bare, trunked standard trees, then M25 and M111 are the logical choices. And one final word of advice: on poor soils, reckon on planting a rootstock a step above that recommended for average conditions.