Trees grown in pots end up with a root system that is coiled up in the shape of the pot, constricting growth once the roots are in the ground. Even if you cut them apart and uncoil them, as any seasoned gardener does, this unnatural contorted condition is an awkward way for a tree to start out. Also, transplant shock is greatly reduced by planting during the dormant season.
Nurseries grow bare root trees in fields of loose soil and harvest them with giant machines that gently lift and pry them from the ground, leaving their root system more or less as nature intended – evenly splayed out like an upside down canopy. Then they stockpile the trees in cold storage to keep them fully dormant before shipping them out. (They would quickly dry out and die if they emerged from dormancy without soil around their roots.)
Local nurseries sometimes stock bare root trees, but they are widely available from mail-order suppliers (see sidebar) who start shipping bare root trees, shrubs, and vines in the first week of January to mild winter regions where the ground doesn’t freeze. But even if you live in a place where you can’t plant until the snow melts away in spring, you need to order now, because they sell out quickly.
After you place an order the nursery will schedule delivery for after the typical thaw date in your region. The goal is to plant them as soon as the ground thaws, but before the buds begin to swell, announcing the arrival of spring.
How to Select Trees and Plan an Orchard
Orchard design is a surprisingly complex craft. Here are the basic rules to follow.
1. Find your USDA plant hardiness zone. (Here is a convenient map.) Then, compare this with the recommended planting zones for the tree varieties you’d like to grow (which is usually part of each listing in a nursery catalog). If the zone number for your region is below the planting zones indicated for the variety, it’s too cold to grow that variety. So, for example, if you live in Kansas City, which is USDA zone 6, figs that are typically rated for zones 7 to 10 will not survive the winter. However, plums, which are generally rated for zones 5 to 9, are a safe bet. Keep in mind that different varieties of the same fruit may be rated for different zones. For example, an unusually cold tolerant fig called ‘Chicago Hardy’ is rated for zones 5 to 10.
2. Find out how many “chill hours” your region gets each winter. (See map.) Compare this with the recommended chill hours in the nursery catalog for each variety you’d like to grow. Sufficient winter chill – measured as the average number of hours below 45 degrees Fahrenheit each winter – are what signals woody species to form flowers (and thus fruit) each spring. Chill hours range from 50 to 1,500 depending on the species. For example, apples, pears, and cherries typically have the highest chilling requirements (900-1,200 hours), while peaches and plums are a little lower (600-900 hours), and grapes, pomegranates, figs, and persimmons need very little chilling (100-400 hours). Nursery catalogs often have a section for “low chill fruits” for folks in mild winter climates. Back to our Kansas City example: This area gets about 1,300 chill hours, so virtually every fruit variety can be grown. Atlanta gets only 800 chill hours, however, which excludes many of the “high chill” fruits. Los Angeles gets about 150 chill hours, eliminating most temperate climate fruit trees, and Miami has zero winter chill – but is great for tropical fruits which don’t require (or tolerate cold), like citrus.
3. Decide what size fruit trees you want to grow. Full-size fruit trees can grow to 20 to 30 feet tall at maturity, but these, which are called “standards,” are rarely used for home orchards because they take up so much space and are hard to harvest. Instead, consider trees that are grafted onto dwarfing rootstock. Depending on the rootstock that’s used, fruit trees can be kept as 5-foot “miniatures,” 15-foot “dwarves,” or to any height in between. The smallest fruit trees are suitable for growing in large tubs on a patio or deck. You should be able to find these diminutive versions at the nursery.
4. Determine how many fruit trees you can grow, which is dependent on your planting space. One tree of each variety is generally sufficient to provide for a family’s needs. No matter the variety, the trees need a location with at least 6 to 8 hours of sun each day, access to water nearby for irrigation, and rich, well-drained soil. In areas where deer are common, a fence (6-foot minimum height) is necessary to protect the trees. Check the mature widths of each tree you want to plant to determine the total number of trees thatj’ll fit in your orchard. In addition to the space needed for each tree to grow to its full width, allow for another 3 or 4 feet between each tree for access, and to encourage good air circulation – one key to warding off fungal diseases. If space is a constraint, consider multi-grafted trees, which have several varieties grafted on a single trunk.
5. Check the pollination requirements for each tree you want to plant. Many fruit trees are self-fertile – meaning they do not require a partner for cross-pollination – but some need another variety of the same species within 50 feet in order to bear fruit. (Most apples, pears, and cherries require cross-pollination; most peaches, plums, and persimmons do not). Nursery catalogs typically include pollination charts for the trees they carry that show which varieties can pollinate each other.
These principles apply to most berries (blueberries, strawberries, blackberries, raspberries, currants, gooseberries, etc), and fruiting vines (grapes and kiwis), as well, which may also be purchased in bare root form, though many of these fruits require the support of a trellis. Nut trees, asparagus, rhubarb, and hops are also traditionally planted in bare root form.
What to Do When You Receive Your Trees
It’s important to plant bare root trees as soon as possible after receiving them. If you can’t plant them right away, remove them from the packaging and store them in the shade with their roots submerged in a pile of slightly moist sand or wood chips – a technique called “heeling in.” The shade encourages them to stay dormant, but so does angling the trunk of the tree so it lays almost flat on the ground (while its roots are buried in sand or woodchips). Before planting, orchardists often soak the roots of their trees in a bucket of water overnight to compensate for moisture loss during shipping.
The planting hole for a bare root tree should be about twice as wide as the diameter of the roots, but no deeper than the depth of the roots. Loosening the soil any deeper often results in the tree settling over time, allowing soil to build up around the base of the trunk – a common cause of fungal diseases.
In heavily compacted soils, pound a piece of ½-inch diameter rebar into the bottom of your planting hole to create 10 or 12 punctures that’ll encourage root penetration and drainage.
Splay the roots out evenly in the planting hole to encourage good anchorage.
Tie your tree to two 6-foot wooden stakes (pounded into the ground about 12 inches from either side of the trunk) to prevent it from blowing over in windy weather. The stakes can be removed after the first couple of years.
If the soil is dry at planting time, water deeply so the roots have ample moisture as they come out of dormancy.
Spread a layer of compost over the planting area to build up healthy topsoil where the surface “feeder roots” will soon grow.
Spread a layer of wood chips over the compost to aid in moisture retention and weed suppression. Just don’t pile the wood chips directly around the trunk – fungal diseases may proliferate if the trunk lacks room to breathe.