by Halton Master Gardener, Liza Drozdov
In this issue, the first of our 4 part series on berries, we’ll focus on strawberries and raspberries. Next time, blueberries and blackberries take centre stage and the final two discuss less common berries such as gooseberries, goji berries, currants and more… Editor
What’s better than harvesting your own fresh berries for dessert or breakfast every day? It’s easy to do and won’t require much space in your garden. You will always find that the berries you grow in your home garden are more sweet, juicy and flavourful than those you buy. That’s because commercially grown berries are harvested at the half-ripened stage to allow for maximum supermarket shelf life. That means that the fruit will only contain about 1% of their maximum fragrance and flavour since aroma and flavour compounds don’t develop until just before fruit maturity. Some fruit will continue to ripen slightly after picking. You’ll see strawberries that are picked pinkish white will turn to red, but they will never reach their full flavour potential or have the full berry fragrance.
Garden varieties of berries you find for sale in local nurseries or online have been bred from berries that originally grew wild. They’ve been selected and crossed to bear larger fruit, more prolific berries, produce for longer seasons or to repeat crop. They grow in a variety of ways: on trees, on shrubs, on canes or as low-growing plants that spread by runners or underground stolons. Berries are an ideal crop for gardeners with restricted space, as they don’t need a lot and many can be successfully grown in containers. They don’t require much care, apart from annual pruning and maintenance–and regular watering of course. If you are growing berries in containers, you’ll need to carefully monitor watering. Don’t ever let them dry out–especially blueberries, as it will disrupt fruit production.
Did You Know? Thanks to very complex scientific classification and nomenclature, many fruits we call berries are not, while others, surprisingly are. Grapes are classed as true berries, as are bananas, watermelons, eggplants, tomatoes and kiwis. Even an orange is a sub-type of berry. However, raspberries, blackberries and strawberries are not true berries. They are aggregate fruits, thanks to their structure with the multiple drupes each containing seeds. But to keep things simple for us non-botanists, I’m going to refer (incorrectly) below to the fruits we commonly refer to as berries .
If you are growing them to eat, make sure you protect your bushes from birds and other wildlife or they will get to the ripe fruit before you do. There are many kinds of berries hardy to Ontario that are easy to grow, from favourites like strawberries and blueberries to more unusual ones like lingonberries and cloudberries. The top four favourite berries in North America, based on commercial production and import quantities, are strawberries, raspberries, blueberries and blackberries.
Even if you don’t plan on eating the berries yourself, grow a few shrubs as a benefit for wildlife, including pollinators and foraging birds.
Strawberries have been cultivated and crossed for millennia and all of the plants you’d purchase from a garden centre or from online suppliers are hybrids. They are self-fertile and will not need to have another type of berry planted near them to ensure pollination. They will grow from zones 4 to 8, with very little care. Like most berries, they were originally woodland plants, but your strawberry plants will produce more flavourful fruit, and a larger crop if grown in full sun. Purchase bare root plants in late spring and be sure to only purchase certified virus-free plants to avoid bringing in problems. Verticillium wilt, mildew and leaf blight are very common in strawberries. Mould is also very common in hot, humid conditions, which are typical in an Ontario summer. Plant your strawberries carefully to ensure they are not too deep or too shallow–which is easily done. Examine the plant carefully and make sure the crown is exactly at soil level. Each plant needs plenty of space to develop and deep root run, like that in a raised bed. Make sure you do not allow the strawberries to blossom in their first year. This will promote root and runner development and ensure a good crop the next summer. Strawberries need very rich moist soil, which is full of organic matter, both to feed the plants and to retain moisture in the soil. They need regular deep watering, ideally at the soil level. The soil should be well drained and in full sun. Use a potassium rich fertilizer like comfrey or molasses tonic every two weeks through the summer. Commercial strawberry fertilizers often contain too much nitrogen, which results in lots of runners and leaves at the expense of berries, and the fruit that is produced will have a crispy texture and less flavour. Enriching the soil with well-rotted manure and compost will help increase the berry crop.
You’ll often see terracotta strawberry jars and towers for sale in garden centres, but they are really not a very good idea. They provide very little room for the required root run, and since the containers are above ground they get hot and dry out too quickly. Strawberries can be grown in containers, providing they are large and deep and they get plenty of water regularly.
Plants should be mulched with straw in order to keep the fruit clean. This should be done after the first green berries appear to prevent and reduce pests, especially slugs that will hide in the mulch. This will also help reduce mould –one of the main diseases of strawberries especially in heavy soil. Black plastic sheeting is another good idea (though it doesn’t look very attractive) as it will keep the fruit clean and warm the soil. Also if drip irrigation is run under the sheeting, it will ensure no excess water stays off the leaves, so mildew becomes less of an issue.
Birds and rodents love to steal berries so you should net them or you won’t get any for yourself.
Do not let them flower/crop the first year after planting. Pinch off any flowers–though it will be heartbreaking to do! They need to develop roots and build up strength for following year.
Do not allow all the runners to remain on the plant as they will definitely reduce your fruit yield. Thin them to just a few, which you can grow on to replace the mother plant in time. After three or four years the plants will become less productive and should be removed and replaced as needed, with newly purchased plants or runners that have been allowed to grow on to fruiting size. You don’t want to replace them all at once or you’ll have no crop that year. Be sure to stagger the plant replacement.
Types of Strawberries:
June Bearing – The most popular strawberry, grown for commercial use. They produce one heavy crop a year, in June/July. Fruit only for 2 to 3 weeks, per variety. You can increase the time your berries will provide fruit by planting several different cultivars.
Ever bearing and Day Neutral – These will fruit less heavily, but do so all season long, from June to frost.
Alpine and Wild – These plants, which must be grown from seed, are quite easy to grow. They don’t form runners so older plants must be replaced by new seedlings as needed. The fruits are smaller, but are very fragrant and sweet. These varieties are also hardier and are less susceptible to pests and diseases.
These are one of the easiest berries to grow, and they crop heavily. If you plant several different varieties you can extend your harvest all summer long. There are red, black and yellow varieties, all readily available in garden centres and online. Raspberries grow on lax, flexible canes that absolutely need to be supported on trellises or post and wire structures. This makes them easy to prune and to pick. If they are not tied in and controlled, the berry patch quickly becomes an unmanageable mess and wading through an overgrown raspberry patch doesn’t make harvesting berries very easy or pleasant to do. They can grow from three to ten feet tall, depending on the variety and their canes are thorny and bristly. Raspberries are vigorous runners that will sucker and spread happily through your garden, so you’ll need to pull out any that pop up where they aren’t wanted. All raspberries produce small white flowers that are very attractive to bees. And, birds will steal the fruit so they need to be protected by netting. Raspberries are hardy from zone 4 through zone 8 and are adaptable to various soils, though they prefer a slightly acidic soil with lots of compost and organic material. They need moisture and will resent drying out or drought. They have shallow fibrous roots, so you must be careful when cultivating or weeding around the plants.
Heavy mulch is a good idea to help preserve moisture. Raspberries will tolerate a lot of shade and still produce fruit, but will do better in full sun. In spring, feed them with a high-potash fertilizer to encourage fruiting. You could grow raspberries in containers, providing they are large enough and you make sure you water frequently. There are some viruses that may attack raspberries. If that occurs, you must remove and destroy the plants. Do not compost them or you will risk spreading the disease.
Types of Raspberries
Summer fruiting: These raspberries fruit on second year canes. The first year the cane will emerge and grow, and at that point they will need to be tied in for next year’s crop. The second year those canes will flower and bear fruit. The next year all of the canes that have borne fruit must be removed at the base. They will not bloom or fruit again and will just help create a thicket of thorn. Select young shoots and tie them in so they can produce next year’s fruit.
Autumn fruiting: These varieties bloom later in the year, on new wood. They are shorter plants and won’t need supports, which makes maintenance much simpler. After they’ve finished fruiting in late autumn, cut all the canes down to the ground.
Be sure to check upcoming issues of Cross-Pollination for more on berries in the home garden!