Growing fruit - your questions answered

Cultivating (and eating) your own home-grown fruit is a deeply satisfying endeavour. But sometimes things can go wrong, and sometimes a handy tip in the right direction makes all the difference.

Here are the answers to some of your fruit questions - and we hope they provide useful answers for you.

My raspberry canes are overgrown with couch grass and weeds. Is it best to dig them up and transplant them?

Digging up your raspberry plants would certainly be the quickest way to tackle the problem, if the couch grass and weeds are growing at the base of your plants.

This should ideally be carried out between September and November. Spreading grasses like couch grass are very difficult to eradicate. If you dig up your raspberries, make sure to carefully pick out any weeds entwined with the raspberry roots.

Make sure you remove the weed roots thoroughly as they can quickly regenerate from these. Regular hoeing in future will keep weed growth in check.

Alternatively, you could use a systemic weed killer containing glyphosate, such as Doff Weedkiller, although these solutions are not selective and will kill your raspberries too if allowed to get on the leaves and stems. Use a cover while spraying the weeds to prevent spray drifting on to your raspberry plants.

How should I look after strawberry plants in winter?

Strawberries are perfectly hardy, and actually benefit from subjected to a bit of cold weather, as it helps to kill off any pests and diseases lurking around. Leave them outside in the ground without cover and they'll be fine. Make sure the soil is well-drained, as sitting in wet soil can encourage the crown to rot.

If your strawberries are in containers, there's a risk of root damage due to compost freezing. Consider moving containers to a sheltered spot by a fence or wall to give them a bit of protection.

Should I remove the runners from my raspberry plants? If I transplant them, will they stay true to the parent plant?

It's a good idea to remove raspberry suckers to keep the plants within their allotted space. When you remove the suckers, try to dig down a little and get some roots as well.

They can easily be repotted at the same depth they were growing in the ground to use elsewhere or share with friends, and will be true to the parent plant.

My cranberry plant is three years old - why hasn't it fruited?

Most fruiting plants will take a few years to mature before producing fruit and cranberries are no exception. It's often a matter of patiently waiting until they surprise you one year with a bumper crop! But in the meantime it is worth reviewing the growing conditions to make sure that you are giving it the best possible chance of fruiting:

• Cranberry plants require moist but well drained, acid soil in a sunny or semi shaded position.

• If you don’t have acid soil then they are best grown in patio containers using a mix of ericaceous compost and John Innes No. 3.

• If possible, cranberry bushes should be watered with rainwater because the lime contained in tap water will reduce the acidity in the soil over time.

Cranberries are self fertile so you won’t need a pollination partner for your plant. When fruits finally begin to develop, you will need to cover the plants with netting to protect the berries from birds.

Should I cut back all my raspberry canes, or just the ones that have fruited?

It depends on the variety you are growing. If you're growing a summer fruiting variety then you only cut back the canes that fruited this year. February is a good time to do this. Leave any young shoots that have appeared from the base of the plant this summer and tie them in to the supporting wires. These will become the fruiting canes for next year.

However if you're growing an autumn fruiting variety (which will just start to be ripening about now) then you can cut all of the canes back to ground level in February, as these will fruit on new canes produced in the spring.

For more information about growing raspberries, take a look at our ‘How to grow raspberries’ article.

Is it possible to grow edible passion flowers in the UK?

It would be difficult to grow the edible Passion Flower (Passiflora edulis) successfully in the UK. This tropical climber originates from Brazil and would need to be grown in a heated greenhouse all year as it doesn’t tolerate frost. Even under cover they may produce a very reduced crop if the weather is dull and cool for long periods, as is often the way with British summers!

How far apart should I plant gooseberry bushes?

Plant gooseberries at a distance of around 1.5m (5') apart in a sunny position in well-drained soil. Do make sure the soil is well-fed with compost or rotted manure, and remove any dormant buds or shoots from the base of the plant to avoid unwanted suckers later on.

I have planted strawberry runners in pots and they have now rooted. Where on the runner do I cut away from the main plant?

Cut the runner close to the base of the parent plant and also at the base of the offspring, with clean secateurs. Provided that the baby plants are well rooted, then they should be grow on happily without the need for the parent plant. Over time the runners will eventually shrivel and die back by themselves, although you’ll probably want to plant them before then!

This is a fantastic way to increase stock of your favourite strawberry plants.

Which strawberry varieties are good to grow from seed for fruiting all summer long?

If you grow strawberries from seed, you'll need to exercise a little patience, as they won't provide a crop until at least their second year. An everbearer like Strawberry 'Florian' or Strawberry 'Sarian' will fruit throughout the summer.

How can I move some immature fruit trees in my garden without damaging or killing them?

There's always an element of risk involved when moving trees, but the younger they are, the greater the chances of successful re-establishment.

It's best to move deciduous trees and shrubs while they are dormant from November to February so you will need to get on with this as soon as possible. Give the roots a wide enough berth and they'll certainly have a fighting chance!

Prepare the tree by pruning out any thin branches and reducing the remainder to create a balanced framework. Make sure that you water well in the days before the move. Prepare the new planting hole before you begin lifting the tree from its current position.

Choose a still, cool day to prevent the roots from drying out during the move. Give the main stem a wide berth and aim to lift a potential root ball diameter of about a third of the tree's height. Dig a trench around the tree and gradually work around the rootball with a fork, easing soil away from the roots a little at a time. Finally, undercut the tree with a spade. Large roots that can't be lifted should be cleanly cut with a knife or saw. Wrap the root ball in a damp hessian sack to hold it together and retain moisture, before moving it to its new home.

Replant your tree immediately. Mix plenty of organic matter (well rotted manure or garden compost) with the soil from the planting hole, and insert a sturdy stake to prevent the plant rocking during windy weather. Gently position the root ball into the hole so that it sits at the same level in the ground as it did in its previous site.

Backfill the planting hole, firm the rootball in, and fasten to the stake with a tree tie. Water well and spread a deep mulch (20cm, 4"") to help conserve moisture at the roots. During the first year after moving you will need to water your tree frequently, especially in dry periods. You may well notice that it experiences a check in its growth this year, but be patient as your tree will need time to re-establish.

My patio apricot tree has produced no fruit, but it has flowered in my greenhouse. On taking it out of the greenhouse, it deteriorated, with leaves curling, discolouring and falling off. What's the problem here?

There are two major reasons why your apricot tree might not have fruited. Firstly, it may simply not be mature enough. Like all fruit trees, apricots are unlikely to produce fruit for at least 3 years but may take longer depending on the growing conditions and variety.

The other possible reason is that the flowers were not pollinated. This can be a problem in a greenhouse where there a fewer pollinating insects but you can improve the chances of pollination by simply opening the greenhouse door each day. You can also try hand pollinating by gently tickling the centre of each flower with a small paintbrush.

The leaf damage that you describe could be Peach Leaf Curl - a common fungal infection of prunus species including apricots. Red blistering on the leaves and die back of branches would confirm the diagnosis. The fungal spores of peach leaf curl require moisture to germinate, so this infection occurs particularly during wet spring weather.

Once the symptoms of peach leaf curl are spotted in spring it becomes very difficult to treat the problem, so most treatments for peach leaf curl are preventative rather than curative.

One solution is to spray your apricot in autumn and again in February with a copper based fungicide. Follow up your February spray with a second application about 2 weeks later. Keep your apricot under cover from late winter to May to keep the spring rains off, thereby preventing the spores from germinating, but make sure that you ventilate your greenhouse as the days warm up in spring. There's more information in our 'peach leaf curl' article to help with this kind of problem.

What's the most reliable form of grafting on fruit trees?

It really depends on what you are trying to achieve and what kind of plant material (age, size etc.) that you are working with.

One of the most commonly seen methods is the whip graft which is used when grafting root stocks and scions together. This basically joins a selected variety onto a rootstock with specific attributes such as improved vigour, dwarfism etc. It is most effective when the plant material used (both scion and rootstock) are no more than ½ inch in diameter.

Many young grafted plants that you buy will have been grafted in this manner, although sometimes a modified cleft graft is used. If you are top working a mature fruit tree to add a new variety to the crown then it is preferable to use a cleft graft. This is better suited to branches no larger than 2 inches in diameter.

Budding is another method to consider. This is particularly useful for plum, cherry, apricots, and peach which are not so easily whip grafted or cleft grafted. If you are hoping to have a go at grafting then the spring is the time to do it, just as the buds of the rootstock are beginning to open.

My apricot tree oozes sap, but produces no leaves or blossom. Is it dead?

This sounds as though it could be one of two problems. Apricots are particularly prone to ‘gumming’ in which the stems exude beads of sticky sap. This is usually caused by a lack of nutrients, or poor soil conditions, and often the tree appears to lack vigour. Gumming can usually be rectified by feeding the tree and improving the soil. Keep the tree well watered, particularly in hot, dry periods and apply a mulch around the base of the plant to help conserve moisture in the soil.

However, if the tree shows signs of die back then the problem may be bacterial canker, which is more serious. Scrape a few bits of bark back on some twigs and branches with your thumbnail to see whether they are still alive. If they are brown underneath the bark then these parts of the branches have died. If they are green, then these twigs are still alive. Check for sunken areas of dead bark where the sap is oozing.

Bacterial canker particularly affects stone fruit trees. The bacteria enters wounds caused by pruning, natural causes and even leaf scars that occur during leaf fall in autumn. This normally happens during wet and windy weather in autumn and spring.

Infection can be controlled by pruning during the summer months only when the wounds will heal quickly. Apricot trees should be sprayed in autumn to help control peach leaf curl, and this will also help to prevent bacterial canker. However, young trees that have become infected are usually best replaced.

How do I prune an apple tree? What's the best time of year to do this?

Apple trees are best pruned during the winter months. Start by removing any dead, diseased or misplaced branches entirely.

If your tree produces fruits only at the tips, it's probably a tip bearer, so you only need to shorten the main branches by a quarter of the previous season's growth. Leave the laterals unpruned.

If your apple tree produces fruit from spurs further down the branch, again, shorten the main branches by a quarter of the previous season's growth. Prune the laterals back to five buds from where they join the main branches.

How do I look after my olive tree?

Olive trees are hardier than many people think, and mature trees can tolerate cold periods of up to -7 degrees C for short periods. In mild areas, you can plant an olive tree in neutral to alkaline, free-draining soil. A few layers of horticultural fleece is enough to protect them.

If you have a potted olive tree, bring it inside or into the greenhouse over winter, and in spring, move it outside to the sunniest part of the garden. Feed and water regularly during summer months.

If necessary, prune in late spring or early summer, removing misplaced growth to encourage new shoots.

How should I overwinter my peach tree?

Peach trees should be perfectly hardy, and a sheltered position outdoors is fine during winter. If the area's covered that's even better, as emerging stems and foliage will be protected from late winter and spring rainfull, reducing the risk of peach leaf curl infections.

Do remember to water them throughout the winter, though, if they're not exposed to any rainfall.

Will young citrus fruit trees grown from pips survive outside in winter?

Citrus seedlings are unlikely to survive even brief frosts, and should be overwintered in a frost-free greenhouse or bright indoor winddowsill.

However, mature citrus trees are capable of surviving brief periods of exposure to below-freezing temperatures.

Are there any evergreen fruit trees?

There are no evergreen fruit trees that will survive outdoors in the UK, but you can grow a small citrus tree in a heated greenhouse or conservatory. Olive trees are evergreen and reasonably hardy, but may not survive a harsh winter. They need a sunny aspect, preferably near a south-facing wall.

Evergreen fruit trees like mango, papaya and guava won't tolerate cool growing conditions, and it'll be impossible to cultivate healthy, fruiting plants in the UK.

Does my hazel nut shrub need a pollinator of a different variety to fruit?

Hazels do crop better if they're pollinated by another variety. If there are hazels growing in nearby hedgerows then these should be able to do the job, but if there are no other hazels nearby, then you'll need a pollinator to get a good crop.

If you decide to invest in another hazel but you're unsure which variety you have, choose one that's distinctly different, such as purple leaved or contorted hazel.

If you do have pollinated catkins on your tree then you'll need to net it, as you'll have stiff competition for the hazelnuts from the local squirrels!

When is the best time to plant out miniature patio fruit trees into pots?

It's fine to plant these out at any time - they're perfectly hardy.

Patio fruit trees are ideal for containers, but it's worht investing in good quality compost from the start, as they'll live in these containers for many years. John Innes No. 3 is perfect.

Can I grow watermelon in a polytunnel?

Watermelons are tropical or subtropical plants so they should thrive in a polytunnel.

Melons are most successfully grown in rich, fertile soil. A liberal application of well-rotted manure or garden compost should be dug into the soil before planting. Watermelons are extremely vigorous (can spread 3-4 metres) so give them plenty of space – plant them about 1m apart. After planting, keep them well watered but they must not sit in wet soil for long periods as this will cause them to rot. Feed with a balanced fertiliser every two weeks until the fruit begins to develop.

Pinch out the growing point on each plant when they are about 2m long, to encourage laterals to form. When the flowers form, choose five female blooms per plant (female flowers have a small bump underneath them). Using a fine paintbrush and the pollen from the male flowers, you can begin to hand pollinate your chosen female blooms. As the fruits begin to set, remove any further flowers and feed with a high potash feed. Be extra careful with watering as the fruits develop - overwatering as the fruit develops can make the melons watery and tasteless.

Regularly ventilate the polytunnel to prevent pests and diseases.

Banner image: Image: agrofruti / Shutterstock

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