Raspberries are delicious and incredibly sweet, the soft delicate fruits are produced on tall, vertical growing stems or ‘canes’. Raspberries can be easy to grow if you have the right conditions. With a little pruning to encourage new stems and some general care and attention plants can remain productive for many years. There are varieties that produce fruit in autumn as well as earlier, summer fruiting varieties that tend to be more popular in gardens. Raspberries are best grow in cooler parts of the country with cold winter temperatures to stimulate production of flower buds and hot dry summers to ripen fruit. There are varieties available that can handle warmer winters and humid summers typical of parts of the north island. In our gardens we generally restrain raspberries by training them against a wall or fence or growing them in front of tight training wires strung between posts. The berries are delicious raw or made into jam, high in antioxidants they are a ‘must’ if you have room for a plant or two. Raspberry plants grow to around head height.
Companions Dill, cornflower – plant nearby but not directly beneath shallow rooted raspberries.
Quantity 2 plants per person.
Traditional red raspberries are these days joined by black and golden yellow varieties.
Aspiring a good raspberry variety with large, rich red fruits that are produced in summer and autumn. Self-fertile.
Summer Suprise produces large red berries in summer. Self fertile.
Ebony a black raspberry that produces well-formed berries over a comparatively long period from December to February. Summer ripening, self-fertile.
Waiau summer fruiting and strong growing plants with good, firm fruit. Self fertile.
Autumns Bliss produces high yields of large, tasty red berries in early autumn on short sturdy canes. Self fertile.
Ivory a yellow form of red raspberry. Fruit are a golden colour and they taste just as good. Autumn ripening, self-fertile.
The best time to plant raspberries is either side of winter in autumn or early spring when plants are dormant and the ground is not frozen.
Plant raspberries in full sun or partial shade with protection from cold prevailing winds that can damage tender new growth and blossom in spring. Good for growing countrywide, they can handle winter frosts down to -10degrees centigrade. They are often trained against trellis or fences or grown individually up a pole. This makes them tidy and productive plants.
Raspberries like a rich, moisture-retentive soil with lots of organic material in it - nothing too soggy though. If your soil is sandy or slightly sticky then you’ll need to add well-rotted compost at the time of planting and continue to mulch with rich compost as your plants get established. You can always grow a raspberry plant in a container or raised bed filled with sterilized topsoil and well-rotted organic compost if you have a sticky clay soil.
Plants should be spaced two per stride in rows that are two strides apart. Soak plants in water before planting them.
Prepare the planting area. Soil should be weed-free and well dug through to at least a full spade’s depth. Add well-rotted compost and if necessary and mix with surrounding garden soil. Carefully remove raspberry plant from container by turning it upside down and holding the plant across the base of its stem with a spread hand. Tap the bottom of the container until the plant and its delicate root ball come loose. If it is in a plastic plant bag simply slit it down the side whilst the plant is standing in the planting hole, you can then slip the plastic bag from underneath. Handle plants by the root ball to prevent damage to stems and shallow roots. Place raspberry plant in a hole that is just larger than the container it came in. The soil level on your plant should be at the same level or just lower than that of garden soil level. Back fill around root ball making sure there are no air pockets. Water well and mulch with a finger-thick layer of pine needles, old straw, shredded bark or untreated sawdust.
If planting in a container ensure it is large enough. Half barrels look good with raspberries and they are the right size too. Use a rich compost with plenty of organic material. And a few spades full of grit or pumice mixed into it to ensure good drainage. Add slow release granules or sheep pellets before planting. When raspberries are grown in containers they should be constantly monitored to ensure soil is moist – particularly in dry weather. Plants are often placed against a wall with trellis on it to which they can be attached or with a metal training pyramid or cylinder standing above the pot.
Keep plants weed free and maintain constant moisture levels – this is especially important during spring and summer when plants are growing and crucial once plants have formed fruit. Always water at the base of plants – avoid splashing foliage as this can spread fungal diseases to which raspberries are susceptible.
Feed: Maintain a nutrient rich layer of mulch around their base through winter. In spring, sprinkle blood and bone meal around the base of plants in spring. Alternatively spread a fresh layer of rich, well-rotted compost beneath plants – not too much though or you’ll end up with lots of soft leafy growth that will attract aphids and make plants vulnerable to fungal diseases. Depending on how well you have composted the ground you might want to give plants an extra boost with some liquid seaweed or worm juice every 6 weeks during the growing season in spring and summer.
Flowering: Raspberries flower in spring and summer, many varieties are self-fertile but growing more than one plant will improve pollination and yields. The flowers are a useful source of nectar for bees that in return help to pollinate them.
Care: Tie stems to training wires or trellis as they grow. Keep plants open and ensure good airflow – especially in warmer areas where humidity can result in fungal diseases like mildew. Raspberry roots are shallow so keep a good layer of mulch around the base of plants and hand weed only around your plants. Raspberry plants tend to produce suckers from their shallow roots, these are removed by following them down below ground and cutting them off at their base.
Raspberries are ripe when their colour deepens and intensifies. Pick them in the morning if you can before the hot sun softens them and they become vulnerable to bruising. There is a skill in picking a raspberry, use thumb and forefinger and gently pinch and pull at the bottom of the cone-shaped fruit. If ripe, the berry will slide off its central white calyx and leave the stem behind. Taste is, of course, the ultimate test of readiness – raspberries have a rich, sweet, rounded flavour. Don’t wash fruit as this causes them to deteriorate quickly.
Storage: Raspberries keep in the fridge for up to a week as long as they are not piled high in a bowl. To freeze, pop freshly-picked, unwashed berries onto a plate or tray in the freezer. When they are frozen add them to a bag. Repeat this process over a period of time until you have frozen and stored all you want. When they are defrosted they will collapse due to excess moisture and are best used in puddings and jams where they are cooked.
Summer fruiting varieties are pruned in autumn when all old canes that have produced fruit are cut back to ground level. Any damaged, spindly or weak canes are also removed. Select the six strongest remaining stems on each plant and tie them onto training wires. Remove all other canes by cutting out at the base of the plant. The young, fresh canes left on the plant will grow to produce the next season’s crop,
Autumn fruiting varieties produce fruit on stems that grow from spring. To prune, simply cut the entire plant back to ground level in late winter. As new shoots are produced in spring these are tied onto training wires. If plants get over crowded in summer reduce canes to about 6 or 8 per plant.
If grown in the right soil and the right location and kept weed-free plants should be less susceptible to diseases such as mildew, botrytis and rust. Aphids, passion vine hopper and scale insects can crowd the soft growing tips and cause them to be deformed. Treat with Garlic spray or Neem oil in spring as soon as you see them. Birds are an issue as soon as fruit start to ripen so protect your plants with mesh or grow them in a fruit cage.