The request came from George Halahan, who lives with his French wife, Elisabeth, in a handsome turn-of-the-century house in St Albans, Hertfordshire. The patch that he is hoping to turn into a fruit garden runs down by the boundary hedge on the left-hand side of the garden. It's a wedge-shaped piece of ground, only about 4ft wide at the top, where it buts on to an old shed, but nearly 10ft wide at the bottom, where it runs into the greenhouse.
It faces south, and Mr Halahan says that the soil is reasonably good. He gardens on fairly stiff clay, larded through with flints. The clay would suit fruit trees. There are already two of them, set side by side at the bottom of the patch by the greenhouse, so in effect the planting space for new fruit is less than 15ft long. One of the trees is a red- flushed young perry pear, growing beautifully, but with branches rather low to the ground.
The other is what is often called a "family" tree: three sorts of apple grafted on to a single rootstock. As with most trees of this kind, Mr Halahan is finding it difficult to keep the balance between the varieties. "Greensleeves", with sharp, juicy, late-autumn fruit is more dominant than either of the other two, "George Cave" and "Egremont Russet". The russet, one of the best flavoured of all English apples, was doing the worst.
You could tell from the rest of the Halahans' garden (well laid out and planted) that they were people who would be prepared to take trouble to get things right. Mr Halahan didn't blench at the thought of the pruning and training that would be necessary if he wanted cordons and fans. "You are looking at a mathematician," said Mrs Halahan. Her husband, she assured me, is both methodical and patient. Lucky her! He specialises in computer software, writing programs for specific companies. She is a homeopath. They both work from home.
The only problem is the hedge - hawthorn, ivy, laurel, and all of it rather high. It would provide shelter from the north but would also suck the ground dry in summer, and gobble the food meant for the fruit. Big, half-standard fruit trees, on non-dwarfing rootstock, would cope with the competition. But here, the object was to cram as much as possible into a small space, and that couldn't be done without using trees grafted on to dwarfing rootstocks. These are very much fussier about the conditions they live in.
I suggested that Mr Halahan put up some supports strung with parallel wires along the back of the plot, leaving a narrow gap so that he could walk down behind the structure to hack at the hedge when necessary. He could grow cordon fruit trees, or a fan, tied in to the wires. Set out like this, a little way from the hedge, the competition for the roots would be kept as low as possible.
Then, along the front of the plot, he could put stepover apples. These are no more than 1ft high, single-arm espaliers which you can train to make a very low, productive hedge. At the top of the plot, the narrow end of the wedge, there would not be enough room between the stepovers and the fruit trees along the back to squeeze in anything else. But the plot widens on its way to the greenhouse. At the lower end, there might be room for a couple of standard gooseberries (dotty, but enchanting to have in a garden) or some compact bush blackcurrants such as the Scottish- bred "Ben Sarek". In front of the stepovers, a row of alpine strawberries could be planted. "Baron Solemacher" is the best, because it does not send out runners. But in the main, Mr Halahan is more interested in growing tree fruit than soft fruit.
Stepover apples should be planted 5ft apart, so Mr Halahan could fit in three different kinds along the front of his plot. To get the best set of fruit, he would have to choose varieties with the same (or overlapping) flowering times. I would avoid "Cox's Orange Pippin". It is a sickly, difficult fruit to grow without endless spraying. "Discovery", "Ellison's Orange", "Fiesta" or "James Grieve" would be more likely to succeed.
Stepovers are usually grafted on to M27 rootstock. This is the most dwarfing rootstock available and trees grafted on to it come into fruit when they are only two or three years old. This sounds like good news, but there is a downside. The root system is sparse and the trees succeed only in very fertile soil. It's also expensive.
When you choose fruit trees, you need to consider the style of the tree (cordon, fan, stepover etc.) hand-in-hand with the site, the cultivar and the rootstock. Mr Halahan will probably succeed with the stepovers on M27 rootstock because his soil is fertile and he is interested enough in gardening to take special care of the trees he plants.
You cannot rely on pruning alone to contain the size of a tree. If an apple has been grafted on to M25 rootstock (M25 is used for big, orchard- sized trees) you can't blame it for trying to fulfil its destiny, which is to grow into a big, beautiful prize-fighter of a tree. Heavy pruning will only make it renew its efforts to do what nature intended.
So if, like Mr Halahan, you don't have much space, you should choose cultivars that by nature are not too vigorous (and that means avoiding the cooker "Bramley's Seedling") and check that it has been put on to an appropriate rootstock. If you wanted to grow the apple "Discovery" as a cordon in a restricted situation on good soil, you might choose M9 as the rootstock. But if you had poor soil you would be better growing a cordon grafted on to MM106, which would give the tree a bit more "oomph".
Mr Halahan said he would like to put a fan-trained plum at the back of his plot. That is a possibility, as it could be splayed out against the supporting wires, with the main branches of the fan trained and tied on to supporting bamboo canes. Pixy is the most dwarfing rootstock available for plums, but even that produces trees at least 10ft high and wide. So there would be room for only one plum, which might bring problems with regard to pollination. Plums set more fruit if they are cross-pollinated with another variety that flowers at the same time.
By planting cordons rather than a fan along the back of the plot, Mr Halahan could introduce greater variety. But plums don't like growing as cordons. I suggested a selection of cordon pears instead. He already has the perry pear and a beautifully grown half-standard "Comice" pear, which he put in a few years ago on the other side of the greenhouse. They would both help with pollination.
Apple cordons can be grafted on to MM106 rootstock or the more dwarfing M9 or M27. The dwarfs can be planted 18in apart, with cordons on MM106 spaced more widely, at about 2ft 6in. Pears, though, are generally grafted on to quince stock, with Quince A being the usual choice for trained trees. There is a more dwarfing Quince C stock available, but if I were Mr Halahan I would go for cordons on the slightly more vigorous Quince A. The hedge is close, the situation not absolutely ideal - but even at a 3ft spacing, he could still fit in four cordons along the back, without tangling with the perry pear. "Beth", "Beurre Hardy", "Concorde" and "Merton Pride" would all be suitable, and should have overlapping flowering times.
And then there was the side of the shed. Perhaps a trident-shaped redcurrant, trained against the wooden boards, where the translucent fruit would hang like a display of outrageous earrings? Even in a patch only 6ft by 15ft, many things are possible.
Trained fruit trees are available from Scotts Nurseries, Merriott, Somerset TA16 5PL (tel: 01460 72306) or Highfield Nurseries, Whitminster, Gloucester GL2 7PL (tel: 01452 740266).