A potted apple tree on a sunny patio can crop for twenty years or more, but only if you treat pruning and root care as one job rather than two. The tree has a fixed patch of soil, so every cut you make above ground needs to be matched by a little attention below it. Get that balance right and you will have blossom, fruit and a pleasing shape in a space no bigger than a doorstep.

Pick a tree that wants to stay small

Start with the rootstock, because nothing else you do will shrink a naturally vigorous tree. Apples on M27 or M9 will settle happily into a container and fruit young. Pears are best on quince C, plums on Pixy, and sweet cherries on a genuinely dwarfing rootstock such as Gisela 5. If you are buying bare-root in winter, ask for a one- or two-year-old maiden with a clean trunk and a good set of roots — it will establish faster than a bigger, older tree.

Choose spur-bearing varieties for restricted shapes. Tip-bearers such as 'Discovery' or 'Worcester Pearmain' carry most of their fruit at the ends of last year's shoots, so hard spur pruning simply removes your crop. For a pot, a spur-bearer like 'James Grieve', 'Katy' or a self-fertile 'Sunset' is far more forgiving.

Plant into a pot at least 35–40cm across, moving up to 45–60cm as the tree grows. Use a loam-based compost rather than a light multipurpose mix; it holds nutrients and water, and gives the roots something to grip.

Building the framework in the first winters

Prune in winter while the tree is dormant, ideally between November and February when there is no hard frost in the forecast. The aim over the first two or three winters is a clear trunk of 45–60cm, then three to five well-spaced branches spreading evenly around it. Shorten the new leaders by about a third, cutting to an outward-facing bud so the centre of the tree stays open and airy. Rub out or cut away anything crossing, rubbing or growing straight inward.

Make every cut clean and just above a bud, sloping slightly away from it. Use sharp secateurs — a ragged cut on a small tree is an open door for canker. Plums and cherries are the exception to winter pruning: leave them until June, when the sap is rising, to avoid silverleaf infection.

Summer pruning and the art of the fruiting spur

This is the technique that keeps a potted tree compact and productive. In late July to mid-August, once shoots have stopped extending but the wood is still pliable, take the current season's side shoots on established spur-bearing apples and pears back to three to five leaves above the older wood. Leave the leading shoot alone to extend the shape.

Those shortened stubs ripen, set fruit buds, and over a few seasons swell into the knobbly spurs that crop year after year. If they regrow the following spring, shorten them again the next late summer. The results are a tidy tree, better light into the fruit, and far less winter work.

Training shapes for tight spaces

• Cordon: a single stem trained at about 45 degrees, spur-pruned each summer. Space them 60–75cm apart along a wall, fence or balcony rail and they will crop from the second or third year.
• Espalier or fan: ideal against a sunny south- or west-facing wall. Tie in shoots with soft twine, loosening the tie as the branch thickens.
• Bush or half-standard: a short leg with an open head of branches — the simplest shape for a freestanding pot on a patio.
• Column or minarette: a narrow vertical form that suits the smallest balconies, where every square foot of growing space counts.

Check ties every year. A tie left tight will strangle a branch long before the tree looks troubled, so always leave a finger's width of room.

Keeping roots healthy in restricted quarters

Roots will circle the inside of a pot within a season or two, and once they are matted the tree stops taking up water properly. Every two to three years, in late winter before growth restarts, tip the tree out, tease the outer roots apart, and trim back roughly a third of the root ball with clean secateurs. Repot into the same container with fresh loam-based compost, or move up one size if you have the space.

Stand pots on feet so water drains freely, and never leave them sitting in a saucer of water over winter. From June, switch to a high-potassium liquid feed to encourage fruit rather than leafy growth, and top-dress each spring with well-rotted compost, keeping it clear of the trunk. Wrap pots in hessian or bubble wrap in cold snaps, or move them against a sheltered wall, because frozen compost does more damage than frozen air.

A simple yearly rhythm

• November to February: winter prune the framework, and root prune if it is due.
• May: thin heavy fruit sets to one or two per cluster so branches are not overloaded.
• June: prune plums and cherries, begin summer feeding.
• Late July to August: summer prune apples and pears into spur systems.
• Any time: water generously — daily, sometimes twice, in hot spells.

Do a little each year and the tree stays in scale, the roots stay lively, and the pot keeps earning its place on the patio.