are an excellent tree fruit that can be used either fresh, canned,
frozen or preserved in jams and jellies. The trees are hardy and,
if given reasonable care, can be expected to grow and produce well
in the Northeast.
Plums can be divided into three different groups--European, Damson
and Japanese. Familiar varieties of the European type are Stanley,
Reine Claude (Green Gage) and the French and German prune (Fellenburg)
types. The European-type plums are best for eating fresh and for
produce very tart fruit which is used chiefly for cooking and preserving.
Examples of Damson-type plums are Shropshire and French Damson.
plums are generally not satisfactory in the Northeast, due to frequent
loss of crops to poor pollination and spring-frost injury. Examples
of Japanese plums are Methley, Shiro, Ozark Premier, Burbank and
important consideration in selecting plum cultivars for planting
is that of pollination requirement. Trees of some plum cultivars
are capable of setting and producing a crop if grown as single isolated
plants. Other plum varieties that do not self-pollinate require
cross pollination for fruit set and development. This means that
trees of at least two cultivars with overlapping bloom periods must
plum trees usually begin to bear fruit three to five years from
planting. The trees have a useful life of 15 to 20 years and come
into full production in about 10 years. Yields of 3 to 5 bushels
per tree may be expected, depending on cultivar.
Desirable nursery stock for planting consists of trees 3 to 6 feet
tall with a trunk diameter of 3/8 to 3/4 inch.
trees should be planted in early spring. Standard-size plum trees
should be spaced at least 20 feet apart in fertile, well-drained
cultural practices in plum production are pruning and training,
fertilizing, mulching, and pest control. Plum trees of the European
type are best pruned and trained to the modified central leader
system. In this system, several well spaced side or lateral branches
(scaffolds) are allowed to develop from the main trunk or leader
of the tree. When the tree reaches the desired height, the central
leader is cut to a short lateral branch.
trees should be fertilized annually for best growth and development.
Suggested fertilizer practice consists of an early spring application
of 1/20 pound of actual nitrogen (8 ounces of 10-10-10) fertilizer
per year for each year of tree age.
with an organic mulch such as straw, sawdust, wood chips and similar
materials can help conserve valuable soil moisture and help control
weeds under the tree.
pests and diseases of plum trees include plum
curculio, European red mite, brown
rot, leaf spot and black knot.
See specific GreenShare Factsheets on these pests and diseases for
more information and control recommendations.
High quality plums are well shaped, colored, firm and free from
defects such as bruising and insect and disease damage. Without
a good knowledge of plum cultivar (variety) characteristics, it
is difficult to detect when a plum is ripe by color alone. Plums
may be various shades of red, blue, green and yellow. The best way
to determine plum ripeness is to apply gentle pressure to the fruit
with the thumb and feel if the flesh is beginning to soften▄if so,
the fruit should be ready for consumption. If not, allow the fruit
to ripen for a day or so at room temperature. With experience with
a particular variety, one can soon correlate color with taste and
judge when the fruit should be harvested from the tree.
storage conditions for plums consist of maintaining a temperature
of 31 to 32 degrees F and a 90 to 95 percent relative humidity.
Under such conditions, storage life of plums is from two to four
weeks. For many, the home refrigerator will be the best method of
preserving the after-harvest life of the fruit until it is consumed
from Richard C. Funt, Ohio State University Extension, 2000