Pruning Raspberries: Summer-Fruiting and Autumn-Fruiting Are Cut Completely Differently

Two kinds of cane, one decision

A raspberry plant produces new canes from the ground every year. A cane in its first year is a primocane; the same cane the following year is a floricane. Everything about pruning comes down to which of those two carries your fruit, and that depends entirely on which type you are growing.

Summer-fruiting raspberries crop on floricanes. The cane grows all through one season, overwinters, fruits in early to midsummer of its second year, and then dies. Autumn-fruiting raspberries crop on primocanes: the cane comes up in spring and fruits at its own tip from late summer into autumn, in the same year.

So the pruning rule follows directly. On a summer-fruiting plant you must keep the year-old canes standing through winter, because they are the crop. On an autumn-fruiting plant you can cut absolutely everything to the ground in winter and still get a full crop, because the crop grows from scratch each spring.

If you cut a summer-fruiting raspberry to the ground in winter, it will grow strongly and produce no fruit at all that year. That is the single most common raspberry mistake, and the plant gives you no warning until midsummer.

Working out which type you have

Plenty of gardens come with raspberries already in them and no label. You can identify the type in one season without knowing anything else, simply by watching where the fruit appears, and until you know, do nothing drastic in winter.

Look at a fruiting cane in the middle of the season. If the fruit is hanging from short side shoots along a woody, brown, tough cane that clearly grew before this year, it is summer-fruiting. If the fruit is at the top third of a green or pale cane that came out of the ground this spring, and it is ripening late in the season, it is autumn-fruiting.

There is a hybrid case worth knowing about. Autumn-fruiting plants, if you leave the canes standing over winter instead of cutting them, will fruit again lower down the same cane in early summer before the new canes crop in autumn. That gives two smaller crops instead of one good one, and the early crop is often poor. It is a legitimate technique but not the default.

Pruning summer-fruiting raspberries

The work happens right after picking finishes, not in winter. As soon as the last fruit is off, the canes that carried it are finished; they will never fruit again and they start harboring disease immediately. Cut them out and the new canes get the light and air they need to ripen wood for next year.

Telling the two apart at that moment is easy. Fruited canes are brown, dry, often with gray flaking bark and the dead remains of fruit stalks. New canes are green or pale, flexible, and have no fruit stalks anywhere on them.

1. Cut fruited canes to ground level Take them right down to the soil surface. Leaving a 6 inch (15 cm) stub gives cane blight and spur blight somewhere to overwinter, and the stub is a hazard when you kneel to weed. Cut flush, and take the prunings out of the bed rather than leaving them on the mulch.
2. Thin the new canes to six or eight per plant A vigorous stool throws far more than it can support. Keep the thickest, straightest canes and remove the thin, whippy ones and anything damaged, aiming for roughly one cane every 4 inches (10 cm) along the row.
3. Remove anything outside the row Suckers that came up more than 9 inches (23 cm) either side of the row line go, however good they look. Pull rather than cut so the piece of root comes with them.
4. Tie the keepers in as you go Space the retained canes along the wires and tie each one individually. Canes tied in while still flexible in late summer bend into position; left until midwinter they snap.
5. Tip the canes in late winter Just before growth starts, cut each cane back to about 6 inches (15 cm) above the top wire, or to the first strong bud below any winter-damaged tip. This stops them whipping about and pushes the plant into producing fruiting laterals lower down.

Do not shorten the new canes in late summer when you tie them in. Their tips are still ripening wood and the length is next year's fruiting area. Tipping is a late-winter job.

Pruning autumn-fruiting raspberries

This is the simplest pruning job in the whole garden. In late winter, before any new growth shows, cut every cane in the bed down to ground level. No selection, no judgement, no thinning: everything goes. New canes come up in spring and fruit the same year.

Do it late rather than early. Canes left standing through winter shelter the crown from frost and give you something to see when you are working around the bed, and cutting in late winter rather than autumn means the plant has finished moving reserves down into the roots. Anywhere the ground stays frozen for long spells, waiting also avoids exposing the crown to hard freezing.

Once the new canes are up, the only job is thinning. Aim for canes about 4 inches (10 cm) apart in the row and pull out the rest while they are still short and soft, in late spring. Thinning early gives you fewer, thicker canes that stand up on their own and ripen fruit before the weather turns.

Cuts that people regret

Most bad raspberry years come from three or four repeatable mistakes rather than from anything exotic. Knowing them is worth more than any technique, because each one costs a whole season and none of them is obvious at the time you make the cut.

Keep a note of which type each row is and the date you last pruned it. Written down once, it stops the argument every winter, and it makes the difference between a bed you manage and a thicket you fight.

1. Cutting a summer-fruiting row to the ground in winter It removes the entire crop. If you have already done it, do not do anything else; the canes that grow this year will fruit next summer and the bed recovers fully in one season.
2. Leaving fruited canes standing all winter They are dead wood carrying spur blight and cane blight into the next season, and they shade the new canes. Cut them out as soon as picking ends.
3. Keeping too many canes Twelve canes on a stool is not twice the crop of six; it is the same crop, smaller, later and moldier.
4. Shortening new canes in summer On summer-fruiting types this removes fruiting wood. On autumn types it delays the crop past the first frosts. Cut the tips only in late winter, and only on summer-fruiting canes.
5. Pruning with blunt or dirty tools A crushed cut on a hollow cane invites cane blight straight in. Use sharp pruners, clean them between rows, and cut flush at ground level rather than leaving ragged stubs.