Nectarines, (Prunus persica nectarina), a subspecies of peaches, are roughly peaches without the fuzz. They are smaller and more aromatic than peaches, but their growing requirements and diseases they acquire are the same. Peaches will grow in U.S. Department of Agriculture plant hardiness zones 6 through 8.
Sun, Soil and Spacing
Nectarines grow best in well-drained soil with a pH between 6 and 6.5. They like full sun. Nectarines grow from 10 to 30 feet tall, depending on whether or not they are pruned to limit their height.
Nectarine roots go to about 4 feet deep. They need space to get sufficient nutrients from the soil. Space nectarine trees 12 feet apart if you have fertile, loamy soil, but give them up to 18 feet of space if you have poor or sandy soil. If you plant them in rows, allow 20 feet between rows of rich soil up to 24 feet between rows of poor soil.
Give newly-planted nectarine trees 1 inch of water per week for six weeks. One inch of water is roughly 6 gallons per square yard of soil.
Mature trees need about 1 inch of water every two or three weeks, especially the six weeks before harvest, which occurs from late spring to mid-summer depending on the cultivar.
Seven to 10 days after you plant a nectarine tree, scatter 1/2 pound of water-soluble 10-10-10 fertilizer 8 to 12 inches from the trunk and water well.
In March and May of the tree’s second and third year of growth, scatter 3/4 pound of 10-10-10 fertilizer under the outer edge of the tree’s branches, called the dripline, and water well. For trees older than four years, scatter 1 to 2 pounds of 10-10-10 fertilizer under the dripline of trees in March and May.
Use hand shears for branches up to 3/4 inch wide, lopping shears for branches 3/4 to 1 1/2 inches wide and pruning saws for larger branches. To prevent the spread of plant disease, sterilize the cutting blades of pruning tools by soaking them for five minutes in a solution of 1 part of household bleach to 3 parts of water, then air dry.
After you plant a nursery sapling in spring, prune it to form a vase-shaped tree, with an open center so your trees will yield larger nectarines that are lower and easier to pick.
Things You'll Need
- Hand pruning shears
- Household bleach
Prune the top of the sapling just above a lateral bud to limit to the tree roughly 30 inches tall.
Prune all but three or four branches angled more than 45 degrees from the trunk and spaced evenly around the trunk. These will become the scaffold limbs, the main nectarine-yielding branches. The lowest branch should be about 15 inches from the ground, measured at it's joint with the trunk, and the highest no more than 30 inches.
Prune all shoots that appear in the interior part of the vase shape during the first year of growth. The following late winter to early spring, remove low hanging, broken or diseased limbs and any vigorous upright shoots that may be growing on the inside of the scaffold branches. The object is to keep the interior open. Once you’ve shaped your tree with scaffold branches, limit the pruning to low hanging, broken, diseased and interior upright shoots until the tree yields nectarines in the third or fourth year.
Nectarines grow on wood that grew in the previous year. Continue pruning upright shoots growing on the interior of mature trees and shoots thinner than a pencil, or that grow in the shade or hang down. The best shoots to leave should be about the width of a pencil and roughly 12 to 18 inches long. Prune one-third of branches longer than 24 inches. The exception to late winter or early spring pruning is vigorously growing shoots that appear in the center of the tree. Prune those in early summer.
Nectarines, along with peaches and apricots, are known as stone fruits, because they have a pit. Fungal diseases common to peaches are also common to nectarines. Most of the diseases are fungal and appear after rain or in hot, humid weather. These can often be avoided by irrigating at the roots, not with sprinklers, and by pruning properly so air can circulate in the interior of the tree.
Nectarines are very susceptible to brown rot, a serious fungal disease. It strikes when nectarines bloom, causing the blossoms to wilt and turn brown. The fungus grows and lingers on the tree, causing the fruit to rot. Numerous commercial fungicides are marketed to combat brown rot. Wettable powder sulfur is an organic solution that may be used by the home gardener.
One brand of wettable sulfur suitable for use in a backpack sprayer calls for mixing 4 tablespoons of sulfur per gallon of water. Spray developing buds in wet, warm spring weather. If wet, warm conditions continue, spray again when the petals fall and a third time when the growing nectarines split their papery covers, called shucks.
Other fungal diseases common to peaches and nectarines:
- Peach scab causes velvety dark spots and cracks, sometimes called freckles,
on nectarines less than 1/4 inch wide. Apply wettable sulfur five times separated
by 10- to 14-day intervals beginning when an infected tree is in full bloom.
- Peach leaf curl causes nectarine leaves to curl and thicken. They
sometimes turn red but eventually turn yellow and fall from the tree, weakening
the tree and causing poor nectarines. Fungicides work if they are applied
before the buds break in spring.
- Gummosis causes gummy sap to exude from the back. Gummosis causes
sunken, diseased areas on the bark of trees that are two or three years old.
There is no practical chemical treatment treatment. You have to cut away diseased limbs.
- Powdery mildew distorts new leaves and shoots and forms
round white spots on immature fruit that turn rusty brown before disappearing
as the fruit matures. Fungicidal sprays are available to treat this disease.
- Phythophthora root and crown rot may stunt the growth of shoots, and the
tree grows scant leaves, which are yellow and small. As the disease progresses,
the scaffold limbs die and the small nectarines will become sunburned. Black
rot may appear where the roots meet the trunk. There is no known treatment for
this disease. Make sure your soil drains well.
Reddish-purple leaves with a white center are a sign of bacterial spot. On the nectarines, they appear as small dark spots that sink into ¼-inch-deep craters as the fruit matures. It typically appears when there are nematodes in the soil, or the tree has not been properly fertilized. Bacterial spot is hard to control and there are no chemical solutions approved for use by home gardeners.
Crown gall, a bacterium found in the soil, causes rough swelling on trunks or roots just below the surface. They start out light green or nearly white, darkening and turning woody as they age. There is no chemical way to treat crown gall.
Nectarines may be infected by European red mites, green June beetles, peach tree borers, Japanese beetles, plum curlulio, oriental fruit motha and stink bugs. There is no single effective treatment for all these insects.
For insects with caterpillars, or larvae, that eat leaves, the best treatment available to home gardeners is Bacillus thuringiensis, or Bt -- a bacterium found in the guts of moths and butterflies. Bt, an organic solution, is sprayed on the tops and bottoms of leaves when the insects are spotted.