Introduction
The cherries sold fresh in most markets are sweet cherries -- they have a thick, rich, almost plumlike texture and sweet taste. If you like your cherries cooked, then you have probably eaten tart cherries, which are juicier and slightly sour.
About sweet cherries
Tart cherries thrive in zones 4 to 6, sweet cherries in zones 5 to 7. Tart cherries are self-fertile, while sweet cherries need a compatible variety for cross-pollination. Choose sweet cherry varieties that are especially adapted to your climate and resistant to the major diseases in your area. Standard-size trees start bearing in about their fourth year, dwarf trees in about their third year. One mature, standard-size tart or sweet cherry tree will produce 30 to 50 quarts of cherries each year; a dwarf tree, about 10 to 15 quarts.
Choosing a site to grow sweet cherries
Choose a sunny site with good air circulation and deep, well-drained soil. Avoid low areas or places surrounded by buildings or shade trees, where cold air settles.
Planting Instructions
Plant cherry trees in early spring. Set bare-root trees atop a small mound of soil in the center of the planting hole, and spread the roots down and away without unduly bending them. Identify original planting depth by finding color change from dark to light as you move down the trunk towards the roots. If the tree is grafted, position the inside of the curve of the graft union away from the afternoon sun.
For container-grown trees, remove the plant from its pot and eliminate circling roots by laying the root ball on its side and cutting through the roots with shears. Don't cover the top of the root-ball with backfill because it could prevent water from entering.
Space sweet cherries on standard rootstocks 35 to 40 feet apart; dwarfs, 5 to 10 feet apart. Space tart cherries on standard root stocks 20 to 25 feet apart; dwarfs, 8 to 10 feet apart. Set trees on standard rootstocks with the graft union a few inches below the soil level. Set trees on Colt dwarfing rootstock with the graft union several inches above the soil level.
Dwarf cherry rootstocks
For home gardeners with limited space, dwarf rootstocks offer a practical solution. The Gisela rootstocks from Germany produce trees that can be held to 10 feet or less, with particularly heavy bearing in their third and fourth seasons. The Damil rootstock from Belgium (technically GM 61/1) will keep trees around 10 feet tall after 15 to 20 years and bears appreciable crops in the fourth and fifth seasons. These smaller trees are much easier to pick and prune, and can be trellised to further manage size and encourage early fruiting.
Recommended varieties by region
Sweet cherry varieties vary significantly in flavor and resistance to cracking in wet weather. In the East and Midwest, soft-fleshed varieties resist cracking better than firm-fleshed varieties. Superior-flavored eastern varieties include 'Kristin' and 'Ulster', though the hardy, widely-adapted 'Stella' and 'Starkrimson' are excellent choices if you have room for only one tree (both are self-fertile). For superior flavor in the West, 'Lambert' is a favorite among connoisseurs. Yellow cherries like 'Stark Gold' are notably bird-resistant and very cold-hardy; 'Rainier' is also high-quality but blushed with red. Large-fruited varieties 'Summit' and 'Royalton' have exceptional flavor and set larger fruits naturally. 'Lapins' and 'Sweetheart' are self-fertile introductions from British Columbia with superior flavor, though they are prone to cracking in humid regions. Interestingly, self-fertile varieties are good pollinators for any other sweet cherry variety, making them useful choices even when space allows for multiple trees.
Ongoing Care
Train dwarf tart cherry trees to a central leader. Train semi-dwarf or standard-size cherry trees to a modified leader. Prune trees every year in late winter to encourage the growth of new fruiting wood. Don't prune in the fall.
Cherries fruit on short-lived buds at the base of one-year-old wood and on long-lived spurs that develop higher up on that same wood during the second season. To improve fruit size, reduce the crop load by cutting out two- and three-year-old branches. Late summer is generally the best time to prune; however, in areas where spring frosts threaten the cherry crop, delay some pruning until just after bloom (when you can assess frost damage) but before the trees leaf out.
Fertilize each spring until trees start to bear, then fertilize only after harvest each season. Cherries are susceptible to a number of different disease and insect pests, depending on region. Contact your cooperative extension office for information on managing pests in your area.
Protecting from birds
Red and dark cherries attract birds, which can devastate a crop. Netting works effectively if there are no gaps. Yellow varieties are naturally bird-resistant. Some gardeners also plant mulberries nearby, as birds prefer them to cherries.
How to harvest sweet cherries
The sugar content of cherries rises dramatically in the last few days of ripening, so wait until they turn fully red, black, or yellow (depending on the variety) before harvesting. Harvest as the cherries ripen over the course of about a week. Pick the cherries with the stems attached, being careful not to tear off the fruit spur that will produce fruit year after year.
Frequently Asked Questions about Sweet Cherries
Ants have taken over my netted cherry tree and the leaves are curling. What do I do?
The ants are a symptom. Unroll one of the curled leaves and you will almost certainly find aphids on the inside surface. Aphids feed by sucking sap, which distorts young leaves into those tight curls, and they excrete a sugary waste called honeydew as they go. Ants harvest that honeydew, and they will tend, defend, and even relocate an aphid colony to keep the supply coming. Deal with the aphids and the ants lose their reason to be up there.
Start with plain water. A strong jet from a hose knocks aphids off the leaves, and dislodged aphids largely fail to get back. Repeat every few days while the population is building. On a small tree this alone often ends it, especially once lady beetles, lacewings, and hoverfly larvae find the colony, which usually takes a week or two.
Insecticidal soap is the next step up, and it works only where it lands, so the spray has to reach the inside of curled leaves and the undersides where the aphids sit. That is the practical difficulty on a tree of any size, and it is why thorough coverage on a mature cherry is often beyond what a hand sprayer can manage. Before spraying anything on a tree carrying fruit you intend to eat, read the current label on the container you own and confirm two things: that the label names cherry or fruit trees, and what interval it requires between the last spray and harvest. Follow that interval, the stated rate, and any protective equipment the label calls for. On fruit that is nearly ripe the honest answer is often that there is no useful window left, in which case wash the fruit, pick it, and treat the aphids as next spring's job.
For the ants themselves, a sticky barrier around the trunk keeps them from climbing. Do not put sticky material straight onto the bark, which damages it. Wrap a band of heavy paper or fabric tree wrap around the trunk first and apply the barrier to that. Check it every few days, because once enough insects are stuck in the band the ones behind them simply walk over the top, and the band needs replacing when it fills. Remember that anything touching the tree becomes a bridge, so keep netting, low branches, stakes, and nearby shrubs from bypassing your band.
A word about the netting, since it is part of this story. Bird netting draped loosely on a tree makes a sheltered pocket that suits ants and aphids and keeps predators out, and loose netting also entangles birds and snakes. Support it clear of the foliage on a frame or poles and secure it at the bottom rather than letting it lie on the branches.
For next year, aphid pressure is greatly reduced by not pushing soft growth. Skip heavy nitrogen fertilizer around the tree, since lush new shoots are exactly what aphids colonize, and check the tips of new growth in early spring when the colonies are small and a jet of water still solves everything.
There are three different insects on my cherry leaves. Which ones are actually a problem?
This is the most useful question a fruit grower can ask, because a tree in June commonly hosts more helpful insects than harmful ones. Three common finds:
A small pale spider, often white or cream with a stripe down each side and roughly the size of a pencil eraser, sitting out in the open rather than in a web, is a crab spider. It hunts by ambush and eats a steady supply of small insects. Leave it alone. Spiders on a fruit tree are working for you.
Small soft-bodied insects clustered on shoot tips and on the underside of curled leaves, in black, green, or gray depending on species, are aphids. The black bean aphid is a frequent one on cherry. These are the actual pest of the three, and the answer above covers them.
A dark, tapered, slightly bristly creature about the length of an ant, often patterned with orange or cream markings, moving about among the aphids is a lady beetle larva. It looks alarming and is one of the best things that can happen to your tree, since a single larva eats aphids continuously through its development. Learn this one and you will stop killing your own allies.
The blackish coating you may notice on leaves under an aphid colony is sooty mold, a fungus that grows on the honeydew rather than on the leaf. It does not infect the tree, it disappears once the aphids are gone, and a rinse takes it off.
Where a real balance has established itself, with predators present and the tree still growing, the right action is often none. A broad spectrum insecticide at that point kills the crab spiders and lady beetle larvae along with the aphids, and aphid populations rebound faster than their predators do, so spraying frequently makes the second half of the season worse than doing nothing.
There are worms in my cherries. Can I tell from a sample, and how do I stop it next year?
Those are fly maggots rather than worms, and in North America two different flies are responsible.
The traditional one is the cherry fruit fly. The adult lays an egg just under the skin of a developing cherry, the maggot feeds inside, and when mature it leaves through a small exit hole and drops to the ground, where it pupates in the soil and waits for the following season. Some individuals stay in the soil more than one winter, so a bad year can echo for two or three seasons even after you improve your sanitation.
The other, and now often the dominant one, is spotted wing drosophila, a vinegar fly that arrived in North American fruit growing regions after most older cherry advice was written. It differs in a way that matters: it attacks sound, ripening fruit rather than damaged or overripe fruit, its populations build very quickly late in the season, and it hits soft fruit of all kinds. If your cherries look fine on the tree and are full of small maggots by the time they are ripe, this is the likely culprit.
A clean handful does not tell you much, because eggs are laid individually and infestation is patchy through a tree. The only reliable check is to look at each fruit for the small entry or exit blemish, or to cut it open. A quicker screen for a bowl of fruit is to submerge it in salted water, about a quarter cup of salt to a gallon, for fifteen minutes or so; maggots leave the fruit and float. Infested fruit is unappetizing rather than dangerous, and cherries that pass the check are perfectly good to eat.
For control, understand that once you can see the damage the season is decided. Everything useful happens either before egg laying or after harvest.
Sanitation is the foundation and it is genuinely effective. Pick the tree clean, including fruit you do not want, and gather every dropped cherry off the ground rather than leaving it. Do this through the season, not just at the end, since fallen fruit is where the next generation comes from. Rake up fallen leaves and mummified fruit when the season closes. Put the collected fruit in the household trash or seal it in a bag in the sun rather than tossing it on the compost heap, where the maggots complete their development happily.
Covering the ground under the tree helps against the soil-pupating cherry fruit fly. Landscape fabric topped with bark, laid out before the fruit ripens and left down through the drop period, blocks maggots from reaching soil and blocks emerging adults from getting out. It does nothing against spotted wing drosophila, which does not depend on that pathway in the same way, so treat it as one measure rather than the answer.
Two more things worth knowing. Fine mesh insect netting, the kind with openings small enough to exclude a vinegar fly rather than ordinary bird netting, put on before the fruit begins to color and sealed at the bottom, is the most reliable non-chemical protection for a small tree. And picking promptly and often once fruit starts to ripen, rather than letting it hang to full softness, cuts spotted wing damage sharply, because the window it exploits is the last few days on the tree.
If you decide to spray, this is a food crop and the label is the whole of the law. Use only a current product whose label names cherry and the specific fly, follow its rate, its protective equipment and its reentry interval, and pay particular attention to the days-to-harvest figure, which is the number that keeps the fruit safe to eat. Timing has to be set by local adult emergence rather than by the calendar, and your Cooperative Extension office can tell you when the traps in your area are catching. Store any product away from children and pets. Older recommendations naming specific chemicals for backyard cherries have not aged well, since a number of them are no longer registered for home fruit use, so shop from the label in front of you rather than from an old list.
Are Nanking and Hansen bush cherries the same as the cherries described above?
No. Everything above is written for tree cherries, the sweet and tart types grown as standard, semi-dwarf or dwarf trees. Bush cherries are a separate group of shrubby species, and the differences change how you plant, prune and pick them.
Nanking cherry (Prunus tomentosa) is a dense, twiggy shrub with softly hairy leaves that commonly reaches 6 to 10 feet unless kept shorter by pruning. It flowers very early, white to pale pink, and carries small bright red fruit. Hansen's bush cherry, sold under that name and as western sandcherry (Prunus besseyi), is lower, roughly 3 to 5 feet, and native to the Great Plains, with blue black fruit. Both are far hardier than the tree cherries above, holding up well into the coldest parts of the country, and both begin cropping in their second or third season rather than the third to fourth year a dwarf or standard tree needs.
The fruit is small and quite tart. It is at its best cooked, which is what the pie and preserve reputation rests on, and it makes good juice and jelly.
One correction is worth making, because it is repeated often and it costs people fruit. Bush cherries are widely described as self fertile. In practice both species set far heavier crops when two or more genetically different plants grow near each other, and Nanking cherry in particular is generally poorly self fruitful. Since most bush cherries are grown from seed, any two plants bought as seedlings will differ genetically, so the practical advice is simply to plant more than one.
Prune them as shrubs, not as trees. The central leader and modified leader training described in Ongoing Care applies to tree cherries. On a bush cherry, take out the oldest, thickest stems at ground level after fruiting and let younger stems replace them, which keeps the plant productive and stops the middle turning into bare wood. That renewal habit is also what makes them useful as an informal hedge, screen or windbreak.
Birds are as keen on these as on tree cherries, and the netting advice above applies. The one advantage is practical: a shrub you can keep at head height is far easier to net completely than a tree, and gaps are what let birds in.
As with every plant in this genus, the fruit is the edible part. The pits and the foliage contain cyanogenic compounds, so do not eat or crush the pits, and keep wilted prunings away from grazing animals.
