Fertilizing Cherries

Control grass or other competing vegetation around the tree for the first few years. A heavy mulch from the tree trunk to the tree's dripline helps conserve soil moisture and control weeds. Fertilize each spring until trees start to bear. Once bearing, cherries need little irrigation or fertilizer in most areas.

If you apply nitrogen to bearing trees, wait until after the fruit has been harvested, but apply it no later than midsummer. This will give the tree a boost toward producing plenty of sugars in its leaves to ripen next year's crop. To prepare the tree for winter, it's a good idea to paint tree trunks white or wrap them with white plastic tree guards. Pull mulch away from the trunk and be sure to harden the tree off.

Be on the lookout for problems with pests and diseases. In the southern parts of the tart cherry-growing area, the only worm to infest the fruit is the larva of the plum curculio, which also attacks sweet cherries. The cherry fruit fly may infest sweet cherries and tart cherries are susceptible to black cherry fruit flies. The apple maggot and peach tree borer may also cause problems.

Brown rot and cherry leaf spot affect both tart and sweet cherries. Black knot and powdery mildew are potential problems for some areas.

Prevent birds from decimating your crop with netting, scare tactics, or barrier-type controls.

Harvesting

One mature, standard-size tart or sweet cherry tree will produce 30 to 50 quarts of cherries a year; a dwarf tree, about 10 to 15 quarts. Wait until the cherries turn fully red to harvest them; the sugar content rises dramatically in the last few days of ripening. You'll need to go over the tree every other day for about a week. Pick the fruit with stems attached, but be careful not to tear off the woody fruit spur, which will continue to produce fruit year after year. If you're using a mechanical cherry pitter, pick the cherries by leaving the stems on the trees. Use these cherries up soon after you pick them because they'll leak juice and may spoil if left out. Using a hand-cranked cherry pitter, you can pit a quart of cherries in 10 minutes.

This fungal disease annually poses the greatest disease risk for fruit loss. Environmental conditions during the 2 to 3 week period prior to harvest can determine whether fruit brown rot will be a problem. Occurrence and severity of brown rot is very dependent on stage of fruit ripeness, time of occurrence of moisture, temperature, and a source of inoculum. As the sugar content increases in the fruit, susceptibility to the brown rot fungus increases. Wet, warm conditions with inoculum sources in or near the orchard during this period create a high risk. In contrast, dry, hot weather during this period greatly reduces the risk even if some inoculum is present. The preharvest/harvest period is the time when the DMI fungicides are very effective when used properly.

The sweets are subdivided into the 'black' and 'white' varieties. All fruiting cherries are hardy in the British Isles, though the blossom may be damaged by spring frosts. Named varieties are propagated on to rootstocks by budding in July and August, or by grafting in March, which would be rather unusual. Seedling Gean Mazzard and the clonal Malling F 12/1 rootstocks are used. Unfortunately, as yet, a dwarfing rootstock is not available and a mature sweet cherry tree may be up to 10m (30ft) tall with a corresponding spread-too large for the average modern garden. Bush Morello (sour) trees rarely exceed a height of 5m (15ft). Sour cherries do well in almost any situation and are particularly valuable for training as fan trees against a north-facing wall unsuited to other fruits. Although sweet cherries can also be grown as fans, they dislike hard pruning and are happiest as standards or half standards given minimum pruning. Plant standards 10m (30ft) apart, half standards 8m (25ft), bush and fan trees 5m (15ft).

Plant firmly and stake securely. Shorten the previous season's growth on the leading branches by half, and side shoots to 8cm (3in). In the spring, mulch the soil surface over the root area with composted vegetable refuse or decayed straw. Do not let weeds encroach for the first few years.

Sweet cherries fruit chiefly on the spurs formed freely on the older wood. Pruning consists in maintaining the tree to an open habit with an evenly balanced head, together with the removal of dead, crossing and rubbing branches. This minimal pruning should be confined to the spring and early summer when infection from silver leaf disease is least likely. Sour cherries fruit on shoots formed the previous season. After the basic fan of branches has been built up by shortening the leaders annually as for sweet cherries, annually replaced side growths are tied in parallel to the permanent branches. The replacement shoots are selected during May to August-one near the base of a fruiting shoot and another at its tip to draw sap to the fruit; all others are pinched out when quite small.

Morello cherries are self-fertile and will pollinate any sweet cherry flowering concurrently. Most sweet cherries are infertile with their own pollen and often with certain other varieties also. The John Innes Institute has classified the sweets into a number of groups but not with their companions (see table above). It is important to select varieties for interplanting whose blossom period coincides or overlaps. A few varieties called universal donors are compatible with all groups flowering at the same time. The dessert cherry season extends from mid-June to mid-August; culinary kinds are used throughout the year for cooking, bottling and making into jam or cherry ale.

Cultivation

Young trees, not exceeding five years old, transplant best. Planting can be carried out at any time from mid October to mid-March, whenever the soil is sufficiently friable to be worked between the roots.

After the cherries have been gathered, the fruited shoots are pruned back at their junction with the selected replacement shoots. The latter are then tied in neatly as before.

Cherries appreciate a spring mulch of farmyard manure at the rate of 51kg (1cwt) to 10 sq. m (10 sq. yd), or 56-84g (2-3oz) per sq. m (sq. yd) of Nitro-chalk if manure is unobtainable, plus an autumn application of 28-56g (1-2oz) per sq. m (sq. yd) of sulphate of potash. Trees on walls respond to being fed with liquid manure.

Protecting the fruit from bird damage is necessary, using fish nets or rayon spider's web material on trees of a suitable size, or by bird scaring where trees are too large to net.