Raspberry Canes
Planting
Raspberries need a fertile neutral soil to crop well (a pH of 6.0-6.7 is ideal) with good drainage in full sun. It is important to plant them in ground that has not grown raspberries or other Rubus (such as blackberries) before. The previous crop will have left dormant 'replant' virus in the soil that will suppress growth of subsequent plantings. This virus can remain viable for up to 30 years. The dwarf summer fruiting variety ‘Ruby Beauty’ is very suitable for container growing. A single plant can be grown in a container that is 30cm (12in) in diameter. Alternatively plant three plants in a container that is 45cm (20in) in diameter. Autumn fruiting varieties can be grown either in the ground or in a large pot. One large pot, 50cm (20in) in diameter can accommodate three canes. Use a good quality loam based compost such as John Innes No. 3 and repot every other year into the same container, replacing 25% of the compost with fresh compost.
All raspberries except very short varieties will need support. Please see ‘Training’ below.
Plant your canes as soon as possible after receipt. Should weather conditions be adverse (i.e. if the ground is frozen or too wet to plant), then the canes should be temporarily heeled in until conditions improve. Dig a hole or shallow trench, lay the canes at an oblique angle and cover the roots loosely with sufficient soil or compost so that no roots are exposed to the air.
Improve the soil structure by thorough digging before planting and if possible mix well rotted manure or compost into the top soil. If the soil is heavy or prone to waterlogging, a raised bed should be constructed.
Soak the roots in water for 1-2 hours, then plant your canes 45cm (18in) apart in the row with the roots well spread out to the depth indicated by the soil mark just above the roots on the main stem, or up to 1cm (½in) deeper. Apply rootgrow™ mycorrhizal fungi directly to the roots before planting - this will help the plants to establish quickly. Tread firmly and water-in thoroughly. If making several rows allow 1.5m (5ft) between them.
Training
All but the shortest of raspberry varieties will require support to keep the fruit up in the air and sunshine - and out of the mud. There are various ways to do this. The two most common are either to tie the canes loosely in clumps around single stakes, or to tie them to two or three horizontal wires (or between pairs of wires) erected between 75cm (2ft 6in) and 1.5m (5ft) above ground. For other more involved methods please consult one of the references mentioned below. The dwarf variety ‘Ruby Beauty’ is self-supporting and should need no additional support.
Pruning
LONG CANES - Long cane raspberries are supplied with approximately 1.2-1.6m (4-5ft) of the previous season’s cane still attached so you can plant them and harvest your first crop from July onwards in the same growing season. Long canes should be planted out as above and immediately trained up and along the supporting wires. Do NOT prune them at all when planting or the heavy crop expected in the first year will be lost. After they have produced their first crop, treat as ‘Summer Fruiting Varieties’ below
SUMMER FRUITING VARIETIES – To encourage vigorous new growth and help establishment cut all stems back to 30cm (1ft) above ground at time of planting. In future years your fruit will come on the previous season's canes which then die back to ground level. To prune therefore in August/September just cut out the canes that have just fruited and train in the new canes, tying them to the support wires from where they will produce their fruiting spurs the following summer.
AUTUMN FRUITING VARIETIES – Cut back your canes to 30cm (1ft) above ground at planting time. In future years your fruit will come in late summer and autumn on the cane that grew earlier the same year, following which it dies back. To prune therefore in winter just cut back all cane to ground level, clearing the way for the new cane to grow and fruit in the following year.
Watering & Feeding
In dry weather water the canes thoroughly once a week, especially during their first spring and summer.
If growing in the ground top-dress liberally in spring using Fruit Feed.
If growing in a pot your canes will need regular feeding during spring and early summer with a balanced (usually liquid) feed. For application rates follow the instructions on the packaging. To keep them growing healthily they will also need fresh compost to root into each year. In the early years this is best done by potting them on into progressively larger pots. Once the final pot size has been reached (we would recommend a pot that is 45-50cm/18-20in in diameter), remove the clump from the pot in late winter each year, cut or chop away about a third of the rootball from the bottom and around the edge, part fill the pot with fresh compost and re-pot. If after re-potting the compost level looks low, top up with additional fresh compost.
If you have planted Long Canes, regular watering and feeding through the first growing season is particularly important while their roots are still establishing.
Weeding & Mulching
Keep the area around the canes free of weeds, particularly during their first year. An annual mulch of well rotted compost will greatly improve moisture retention and soil structure, and help suppress unwanted weeds.
Pests & Diseases
Raspberries are generally trouble free but watch out for damage to the fruit from the raspberry beetle. If troublesome this may be controlled by installing raspberry beetle traps. Any chemicals should be used strictly as per the manufacturer's instructions.
Further Information
For further information refer to RHS Growing Fruit by Harry Baker. Useful information can also be found on the RHS website.