Life's a bowl of cherries

You love eating cherries, but they are enormous trees that need acres of space and are difficult to harvest, right? Well that may have been true once, but certainly isn't the case now if you look to modern varieties grafted onto dwarfing rootstocks or trees trained as fans. Coupled with this and with a little forethought, that other perennial problem - birds - can also be kept under control.

I spent a few wonderful hours eating cherries at the national fruit collection which is situated at Brogdale Farm in Kent and was soon convinced that at least one of the new trees I have been intending to plant this winter should be a cherry. But what conditions do they need, how do we grow them and what are the varieties to look for?

Sweet or sour?
Until relatively recently sweet cherries were considered too large and vigorous to grow in an ordinary garden and the more compact acid varieties such as 'Morello' were more common although they still made large trees.

Now new varieties and rootstocks have widened the choice and it is perfectly possible to grow sweet varieties in even a small garden; which you choose really comes down to personal taste - whether you prefer your cherries bitter sweet or just plain sweet.

Rootstocks
Colt is a popular rootstock and will produce a mature tree of about 5m (about 16ft) in height. However, because more dwarfing types have since come along, Colt is more commonly used for the less vigorous acid cherries and Gisela 5 and Tabel are now more popular with some suppliers. These are naturally more dwarfing than Colt and you can expect a tree grafted onto these to reach about 2.4m (8ft) in height. If growing more than one tree, allow about 1.5m (5ft) between each when grown on Gisela 5 or Tabel.

As an alternative to Gisela 5 or Tabel, some suppliers 'double work' their trees - grafting a second height-restricting variety between the Colt rootstock and the fruiting variety and trees grown in this way commonly reach a mature height of about 3m (9ft).

Fan-trained trees are usually grafted onto Colt rootstocks.

Site and soil
The other great bonus of growing cherries is of course the beautiful spring blossom so if growing your tree in the garden, try to find a spot for it where it can be seen from the house for some early colour. However, because they flower early in the season (early April in the south, late April in the north) trees do require shelter from frost and cold winds - in exposed gardens this makes the growing of a fan against a sunny south or west-facing wall the best bet.

The soil needs to be free draining, but moisture retentive and reasonably deep and fertile. Dig in plenty of well-rotted compost or manure prior to planting and also some grit if the soil is heavy and poorly drained.

It is especially important to improve the moisture-holding qualities of the soil when planting a fan close to a wall or fence where it is likely to be much drier. Keeping the moisture content reasonably even is important since if cherries receive lots of water when the fruit is developing, it may split.

The compact cherries are ideal for growing in pots and this allows the trees to be moved under cover when flowering and fruiting, but kept outside at other times such as in the autumn and winter to give them the cold spell they need to initiate fruit production.

Grow your tree in the largest container you can accommodate (and move), preferably using John Innes compost no 2 or 3 as this adds stability to the pot and is better for long-term planting. In pots it is even more important to check watering regularly to maintain growth and to prevent fruit splitting as the crop ripens.

Each year remove the top 2.5cm (1in) of soil and replace with fresh together with a sprinkling of controlled-release fertiliser such as Osmocote or use bonemeal if you prefer to garden organically.

Pruning and training
Sweet cherries grown as bushes in the garden should be pruned as little as possible and always in spring and summer when growth is in full swing. This reduces the likelihood of bacterial canker and silver leaf diseases entering pruning cuts.

In the case of bushes, simply remove dead, diseased or damaged growth as it is seen. It is also important to keep the middle of the tree open to allow air and light to enter, so excessive growth can be removed here.

As mentioned acid cherries are more vigorous so require a little more pruning. Here one or two older branches can be removed or shortened on established trees each year to encourage new shoots to form and cut back up to a quarter of the fruited shoots to a new bud or sideshoot near the base after picking.

Fans do require more pruning to maintain the shape. This is again done in early summer and involves tying in young shoots to fill in any gaps in the framework and cutting back all but the leading shoots to eight or 12 leaves from the base. Once the crop is picked, shorten these shoots further to leave three leaves. Leading shoots can be cut back once they have filled their allotted space.

Pests and diseases
Birds present the biggest problem; net the tree even before the fruit is properly ripe. Alternatively move miniature trees into the protection of a greenhouse or polytunnel or protect low-growing bunches on large trees by hanging some crop protection netting or old nylon curtains over them.

Bacterial canker is a real threat and can greatly affect the cropping potential of the tree and even, given time, kill it altogether. The bacteria can enter the tree through any tiny wound including pruning cuts. Restricting pruning to the spring and summer when the sap is rising helps by pushing the spores out of the cuts rather than drawing them in. Disease spread can be restricted by pruning back affected shoots (look for the knobbly cankers on the stem which may bleed a thick amber liquid) well beyond the point of infection.

Silver leaf may also kill the tree, but is often restricted at least at first to one branch or side of the plant. Symptoms include silvering of the leaves and a brown staining within the tissue of the branch when cut with secateurs. Prune out affected branches as they are seen beyond the point of staining.

Drought followed by heavy rain can cause the fruit to split. Improve the soil and water during dry spells.

Six of the best
Literally hundreds of cherry varieties have been produced over the years and the magnificent national collection held at Brogdale in Faversham, Kent, holds no less than 320 of them. As regular readers will have seen, we paid the collection a visit back in July during the Cherry Festival and while there asked the experts for their selection of the best for garden growing. Here are their recommendations, all of which are self fertile and should be freely available from specialists such as those listed below:

• 'Sunburst' - Near black fruit ripen in mid-July and can be stored for a few days after picking
• 'Stella' - One of the first self-fertile varieties. Dark red fruit maturing in late July and a good pollinator for many other varieties.
• 'Sweetheart' - One of the latest to crop, producing near black fruit.
• 'Celeste' - Compact tree producing large red fruits from mid-July. Ideal for pots.
• 'Lapins (aka Cherokee) - Crops in mid-July producing red fruits. Resistant to splitting and heavy yielding.
• Brogdale also recommends 'Penny'. This is not self fertile but a really good late cherry and will be pollinated by any of the self fertile varieties listed. 'Penny' produces dark red fruit, ripening to black in late-July. It is British bred so well-suited to our conditions.

To see the Life's a bowl of cherries gallery, click here.