Gadenin日本語Get the appPlant while the canes are dormant
Bare-root canes go in during the dormant season, any time the ground is neither frozen nor waterlogged. Early in the dormant season is better than late: the roots make some growth whenever the soil is above about 45F (7C), so canes planted early are already anchored when growth starts. Canes planted right at the end of dormancy often make a weak first summer because the top starts before the roots do.
Container-grown canes can go in at almost any time of year, but they still establish best in the dormant season and they still need watering through their first summer. If you have to plant one in leaf, keep the rootball intact, water it in hard, and accept that it will be a season behind a dormant cane planted properly.
Bare-root canes arrive with the roots exposed and they will not forgive drying out. Heel them into spare soil or a bucket of damp compost the day they arrive if the bed is not ready, and plant within a week.
The row has to be in the right place from the start
Raspberries spread underground. Every plant sends out roots that push up new canes, called suckers, well away from where you planted it, and after three or four years those suckers are in the path, in the lawn and in the bed next door. Nothing you do later is as effective as choosing the site properly and installing a barrier at planting time.
Pick a spot in full sun with shelter from strong wind, and keep the row clear of anything you will not want raspberries in. Do not plant where potatoes, tomatoes, peppers, aubergines or strawberries have grown in the last four years: those crops leave verticillium wilt in the soil and raspberries are badly affected by it. Avoid ground that stands wet in winter, because root rot kills more raspberries in gardens than any pest does.
| Site factor | What raspberries want | What goes wrong otherwise |
|---|---|---|
| Light | Full sun, six hours or more | Thin canes, small crumbly fruit, more gray mold |
| Drainage | Soil that never stands wet | Root rot, canes wilting in midsummer with fruit on |
| Soil pH | 6.0 to 6.5, slightly acid | Yellow leaves with green veins on chalky ground |
| Previous crop | Not after potato family or strawberry | Verticillium wilt; canes die one side at a time |
| Wind | Sheltered, but with air moving | Canes snap at the tie, fruit is blown off |
Spacing, and why wider is better
Space canes 18 inches (45 cm) apart along the row and leave 6 feet (1.8 m) between rows. That looks absurdly generous when you are handling six bare sticks in the dormant season, but each of those sticks turns into a stool throwing six to eight new canes every year, and the row closes up on its own by the second summer.
Crowding is the root of most raspberry problems. A dense row holds humid air, and cane blight, spur blight and gray mold all follow humidity. It also shades the base of the canes so the lower fruiting laterals never crop. Keep the fruiting row no more than 18 inches (45 cm) wide and pull out anything that comes up outside that strip.
| Layout | Cane spacing | Row spacing | Notes |
|---|---|---|---|
| Single row against a fence | 18 in (45 cm) | One row only | Easiest to pick from both sides if the fence is open |
| Two or more rows | 18 in (45 cm) | 6 ft (1.8 m) | Less than this and you cannot get a barrow between them |
| Autumn-fruiting block | 15 in (38 cm) | 4 ft (1.2 m) | Cut to the ground each year, so a tighter block works |
| Large container | One cane per 12 in (30 cm) pot | Not applicable | Three canes in a 18 in (45 cm) tub at most |
Planting depth and the first cut
Raspberry roots are shallow and horizontal, not deep. Set the cane so the old soil mark on the stem is level with the surface, which usually means the roots sit only 2 to 3 inches (5 to 8 cm) down. Planted deep the crown sits wet and the buds that should make next year's canes rot before they emerge.
Then cut the cane you just planted down to about 10 inches (25 cm) above the ground. This is the step people skip, and it costs them. The stub is there only to mark the row and to feed the roots for a few weeks; the canes that will actually crop come up from below ground later in the season. Leave the whole cane on and the plant tries to fruit on it, exhausts itself and produces fewer new canes.
- Dig a shallow trench, not a hole Take out a trench a spade wide and about 4 inches (10 cm) deep along the marked line. Spreading the roots sideways in a trench beats cramming them into a round hole, because that is the direction they grow anyway.
- Work compost into the bottom Fork a bucket of well-rotted compost or leaf mold per yard of trench into the base. Do not put fresh manure or a heavy dose of general fertilizer directly against the roots; it scorches them and pushes soft growth.
- Spread the roots and set the depth Lay each cane in with the roots fanned out and check the soil mark on the stem. Backfill so that mark ends up level with the bed surface, and firm with the ball of your foot rather than stamping.
- Water in, then mulch Water thoroughly enough to settle soil into every gap between the roots. Mulch 2 to 3 inches (5 to 8 cm) deep with compost or bark, keeping the mulch an inch clear of the stems.
- Cut the cane back to 10 inches (25 cm) Make the cut just above a bud. If the cane pushes leaves from the stub, fine; if it does nothing at all and new shoots come out of the soil instead, that is exactly what you want.
Autumn-fruiting canes get the same treatment, but you can cut them right down to soil level instead of leaving a 10 inch stub, because they will crop on the new canes in their first summer.
Stopping the suckers before they start
The cheapest insurance you will ever buy for a raspberry bed is a root barrier put in at planting. Sink a physical barrier along both sides of the row before the canes go in, and the suckering stays inside a strip you can manage in ten minutes a year instead of spreading across the garden.
Where a barrier is not practical, mow or hoe the ground either side of the row. Suckers that appear in mown grass simply do not survive regular cutting. In beds, pull suckers rather than cutting them: a sucker pulled sharply comes away with the piece of root that produced it, while one cut at ground level branches underground and comes back as three.
| Method | How deep | How well it holds |
|---|---|---|
| Rigid root barrier or paving slabs on edge | 12 to 18 in (30 to 45 cm) | Very good; roots are shallow so this contains most of them |
| Mown grass either side | Not applicable | Good, as long as you never stop mowing |
| Pulling suckers by hand | Not applicable | Good if done twice a season, in late spring and late summer |
| Growing in a large container | Container depth | Total, but you must water daily in summer and repot every third year |
Write down the planting date and the exact position of the row, and sketch which end you started from. Three years on, when you are deciding whether a cane in the path is a wanted sucker or an escapee, that sketch is the only thing that answers the question.