Gardeners who dream of planting fruit trees usually have sweet cherries right at the top of their list. The plump, glossy fruits are sweet and luscious. They ripen early in summer, when we are good and ready for a change from store-bought apples, oranges, and bananas. And cherries are so tender that really great ones are hard to get in the store.
For most of us, however, those bowls of sweet homegrown cherries have had to remain a dream because raising them has presented problems. The trees grow huge - 40 feet tall or more. Big trees are hard to pick, difficult to spray safely and impossible to net from birds. What's worse, to get cross-pollination, you needed to plant two of these giants, unless you restricted yourself to 'Stella', the only readily available self-fertile cherry variety, and even one 'Stella' tree is too big for most yards.
But suddenly, cherries have gotten a lot easier, This year there is very good news for anyone who wants to try his or her hand at sweet cherries. Finally, there is a rootstock that will keep the trees really small. "We're talking about trees that will be around 10 feet tall after 15 or 20 years," Bob Anderson, a sweet cherry breeder at the New York State Agricultural Experiment Station in Geneva, told me recently. "You'll be able to pick and prune standing on the ground for a good part of the lifetime of the tree."
The relatively new rootstock is named Damil from Belgium. It's the first in a new wave of cherry root- stocks developed in Europe in the '60s and '70s that have been tested in the U.S. and Canada for the past 10 years. Darmil (technically called GM 61/1), available to gardeners this year, bears its first appreciable crops in its fourth and fifth seasons, a year or two earlier than standard cherry rootstocks do. The Gisela (ghee-se-la) rootstocks from Germany also produce trees that can be held to 10 feet or less. These rootstocks have commercial cherry growers even more excited because they bear so heavily and so quickly - in their third and fourth seasons.
You'll probably want to consider trees with more exotic fruit quality than the standards - 'Bing' in the West and 'Hedelfingen' in the East. That's not to say that those two varieties aren't excellent fruits, but there are richer flavors available.
Among connoisseurs, 'Lambert', a western variety, is a favorite. For the East, 'Kristin' and 'Ulster' have a similar flavor. Eating cherries like these is somewhat like eating chocolates. The strong cherry flavor and the tartness that goes with it, sometimes fatigue your tongue. A dozen of these high-powered cherries can taste like a lot.
What makes a variety suitable for the East versus the West, by the way, is its tendency to crack in rainy weather. This happens when moisture enters through the skin of the fruit, not the roots. Very sensitive varieties can split in the slightest drizzle or mist. Even in the relatively dry cherry districts in British Columbia and the western states, a bit of rain sometimes ruins part of the crop. The firm- and crisp-fleshed varieties are most likely to crack; soft-fleshed varieties resist cracking. In the East, you should grow only the most crack-resistant varieties. Westerners can grow pretty nearly anything they want.
Some of the highly flavored cherries have other qualities that may help you narrow your choices. If you have room for only one dwarf tree, you'll have to choose a self-fruitful variety. 'Lapins' and 'Sweetheart', introductions from British Columbia, are considered very fine, approaching 'Lambert' for flavor. But 'Lapins' and 'Sweetheart' are prone to cracking. In the East and Midwest, plant the self-fertile 'Stella' or 'Starkrimson', which were introduced in the 1970s. Their flavor is not of highest quality, but both varieties are widely adapted. And where space is tight, either one of these is a lot better than no cherries at all! High-quality self-pollinating varieties for east of the Rockies are in the works from the research stations in Geneva, New York, and Vineland, Ontario.
Another advantage of the self-fruitful varieties is that they are all good pollinators of any other sweet cherry variety. The sweet cherry family is full of pollen incompatibility and picking two that go well together is a little like ordering from a Chinese menu. So even if you have room for two dwarf cherries, something like 'Lapins' or 'Sweetheart' may still be a good choice.
Another way to get dependable pollination is by choosing a yellow cherry. Yellow varieties are also usually bird-proof. The top choice is 'Stark Gold'. It's a pure yellow with no red blush, and red is what the birds seem to go after. In the West, gardeners could also grow 'Rainier', a very large cherry, but it's blushed with red. Either of these has very high-quality flesh and will pollinate virtually any other sweet cherry. 'Stark Gold' originated in Nebraska and is one of the most cold-hardy and latest-blooming sweet cherries.
If you grow the classic red cherries, you will certainly have to stop the birds. What can you do about them? "Try all the tricks you can find in the folklore and the scientific lore - from preventing the first bird from finding the crop to netting the tree. But how the heck do you do that," Ed Proebsting says, laughing. Proebsting, a researcher at Washington State University in Prosser, has spent his entire career looking for better methods of sweet cherry production. "We don't think much of the scare-eye balloons but use them anyway. Netting works, but there can't be the smallest hole or the birds will find it." Or you can grow mulberries; birds seem to prefer them to cherries.
Most people seem to prefer their sweet cherries large. And there are good reasons for that. Bigger cherries are much easier to pick, for one thing. But they also usually taste better. That's because cherries, as a rule, tend to set too many fruits. And when a tree oversets, the fruit stays smaller and doesn't develop as sweet or as full a flavor. Ripening is often delayed, too.
It isn't practical to thin cherries by hand the way we do larger fruits like apples or peaches. But there are two ways around the problem. You can plant very large-fruited varieties. "When cherries are very big, it's usually because the variety is somehow self-thinning, for some pollination biology reasons that we don't yet fully understand," says Geneva's Bob Anderson. 'Summit' is one of the best-flavored large varieties. It was introduced by the Summerland fruit research station in British Columbia, and, surprisingly, is somewhat crack resistant, perhaps because the flesh is a little soft. It's very popular with commercial growers in France, according to David Lane, the cherry breeder at Summerland. Another gigantic cherry is 'Royalton', released by the Geneva, New York, experiment station. 'Royalton' also has exceptionally fine flavor, though it's too new to say how widely adapted it will prove to be.
The other way to get bigger cherries is to reduce the crop load - not by thinning - by pruning. 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. Lighten the crop load by cutting out two- and three-year-old branches. In general, the best time to prune cherries is late summer. Where spring frosts are a serious threat to the cherry crop, however, a good tactic is to save some pruning for the days right after bloom - when you can assess how high the losses from the frost are - but before the trees leaf out, according to Ed Proebsting in Washington.
Sweet cherries on short trees will revolutionize home cherry growing. Commercial growers will probably plant these new cherry trees on wire trellises, and gardeners should consider doing the same. Tying the tree to a framework helps to restrict the size even more and to push the tree into early fruiting. Trellised cherries are also easier to cover with bird-proof netting.
One of the fundamentals in fruit growing is that the smaller the tree, the easier it is to grow the fruit to perfection with a minimum of spraying and time spent. Paradoxically, smaller trees always translate to bigger crops per square foot of space. So as we shrink our cherry trees, we gain not only higher yields, but the opportunity to try even more varieties. And I don't know about you, but I'm starting with the biggest, most richly flavored one I can find - flavor fatigue sounds pretty good to me!