General Advice for Growing Raspberries
If you’ve not grown raspberries before then the autumn fruiting varieties are easier to manage than the summer fruiting varieties. Autumn fruiting raspberries also have a longer cropping season, starting in late summer and lasting until the frosts.
Raspberries like rich soil with good drainage. You will need to keep them well watered. Feed with a general purpose fertilizer in the spring. Applying a mulch of well rotted manure in the spring helps feed the plants and keep them moist.
They suffer from iron and magnesium deficiencies in alkaline soils. If you have chalky soil either treat your raspberries with a chelated/sequestered iron and magnesium preparation or grow autumn fruiting varieties in pots in a neutral or ericaceous compost. For the same reason do not water raspberries with tap water in hard water areas.
Raspberries are often sold as dormant canes (raspberry stems are known as canes) with bare roots. These are sold for planting in autumn or early winter. Try to plant them to the same depth as the soil mark on the cane.
Container grown plants can be planted at any time as long as the soil isn’t frozen. The variety you choose to grow will often depend on how much room you have and how much effort you wish to put in. Lazy gardeners should choose an autumn fruiting variety.
Autumn Fruiting Raspberries
Autumn fruiting raspberries produce fruit on the current season’s canes. This makes them more compact and better suited to growing in pots or smaller spaces.They are often sold as container grown plants so you can enjoy fruit in the first growing season. Simply plant to the same level as the soil in the container and keep well watered. You can provide some support by tying the stems to garden canes if necessary.
Cutting canes back to ground level as soon as they have finished fruiting helps prolong the fruiting season. Cut all remaining canes down to ground level at the end of the season. You will also need to remove suckers (shoots that appear more than about 20cm from the main plant). Autumn Bliss is a reliable and widely available variety.
Summer Fruiting Raspberries
Summer fruiting raspberries produce fruit on 2 year old canes. Once the canes have finished cropping they should be cut down to ground level. For the best crop, survey the newly grown canes and select the strongest looking 8 new canes per plant and cut the rest back to the ground.
Summer fruiting raspberries require training and so are usually grown in rows with support wires. There are several different arrangements of posts and support wires that you can use, but the basic principle is the same. You want to support the raspberry canes allowing air and light in. Good training also makes harvesting and pruning easier too. Many gardeners will train all the first years growth to one side of the plant and the second years growth to the other. Once the canes have fruited they are cut down to ground level leaving space for new growth to be tied in next year.
In the spring trim the canes to about 1.2m, removing any frost damaged wood in the process. Make sure the canes are securely tied in to the supporting wires.
You will also need to remove suckers (shoots that appear more than about 20cm from the row) as they appear to avoid ending up with a weak and straggly mess of canes.