Whatever variety you select, it will likely be grafted to a rootstock that determines its vigor and thus tree size. Sour cherries on seedling rootstock mature at a manageable 10 to 14 feet high, but sweets can reach 40 feet or more. Mahaleb rootstock, the standard choice for sour cherries, requires well-drained soil. Mazzard rootstock, propagated from the seed of a wild sweet cherry, tolerates wet ground but bites the dust if the thermometer drops much below 0°F. Backyard growers should consider dwarfing rootstocks, like the Gisela series from Germany.
Space sour cherries 8 to 12 feet apart. Sweet cherry trees on standard rootstocks need to be 30 to 35 feet apart, with dwarfs spaced as little as 6 to 10 feet apart. Keep soil around young trees free of turf and weeds for the first few years. A uniform ring of mulch benefits trees in these wood-growing years.
In the development years, encourage strong scaffold branches by pruning away those that are crowded or weak. Once fruiting begins, pruning consists mainly of thinning growth each year to allow sunlight to filter into the canopy. A tendency toward stoutness in cherries makes for less whippy growth overall in the tree’s upper reaches.
Cherry wood has a tendency to “go blind”—cease producing flowers and fruit—rather quickly. Buds that flower one season no longer are in the game, so to speak, pushing the productive zone further and further out from the trunk. Pruning cuts made into 3-year-old wood can stimulate the growth of productive stems from older limbs.
Important allies for fruit trees include the fungi found in a living soil. Mycorrhizal species of fungi form a symbiotic relationship with the trees’ feeder roots, delivering balanced mineral nutrition in exchange for carbon-rich sugars. To make sure this fungal connection is present, sprinkle a commercial mycorrhizal inoculant directly on the tree roots at planting or stir it into the soil in the root zone.
Trees depend equally on saprophytic fungi to break down soil organic matter and thus make nutrients available. Create a “fungal duff” beneath fruit trees by mulching haphazardly with deciduous wood chips, made from brush and branch ends, where a greater proportion of mineral-rich bark will be found. A valuable component of this mulch layer are prunings from assorted hardwood species—including your cherry trees—snipped to short lengths to lie flat. Rake leaves inward each fall and cover with a smattering of compost, as well. All this matches the ecology found on the forest edge, leading to exactly the right kind of fungal presence necessary for tree health.
Photography by Woodystock; Flowerphotos.