Friday, 24 April 2015 19:45

How do Plums grow?

Plums are one of the earliest and most widely cultivated fruits known to humans.

  • Latin Name:

    European plum: Prunus domestica

    Japanese plum: Prunus salicina 

  • Growth:

    USDA Hardiness Zones 4-9 Click here to view USDA Plant Hardiness Zone Map.

    Plums grow on fruit trees that belong to the rose family and are related to other stone fruit such as almonds, apricots, cherries, nectarines, and peaches. Although there are more than 40 types of plums, most grown in the United States are cultivars of European or Japanese varieties.

    In North America, European plums can be grown in most USDA hardiness zones, including spring frost-prone zones 4 and 5, while Japanese plum trees are better suited for warmer regions where peach trees thrive, hardiness zones 6 to 9. Click here to view USDA Plant Hardiness Zone Map.

    Japanese plum trees typically produce more fruit than European trees, and thus require more pruning. However, European trees are the preferred variety for many North American gardeners because they produce more flavorful fruit, are hardier, and thus easier to grow and maintain. Today, there are also several hybrid-variety “American plum” trees that combine the hardiness of European plums and the high yield of Japanese plum trees.

    All varieties of plum trees thrive in moderately fertile, well-drained soil in full sun. Japanese plums tend to bloom in late winter and early spring, which makes their young buds susceptible to frost damage. European plums bloom in late spring, after the danger of frost in most areas.

    A plum tree takes four years after planting to begin bearing fruit. Japanese plums grow 8 to 9 feet tall and are ready for harvest approximately two months after the last frost. American varieties are harvested in mid-summer. European varieties grow to 25’ tall and are harvested in late summer and early fall.

  • Propagation:

    Plum trees can be grown from cuttings, grafting, or seed.

    The best propagation method is by taking cuttings from a tree that is a known producer. Plum trees grown from seeds may not grow true to form if they are a hybrid variety.

  • Harvest:

    Plums have the best flavor when allowed to ripen on the tree. Japanese plums typically begin to mature in late spring through mid-summer, while American varieties ripen in mid-summer, and European, in late summer to early fall.

    To check for ripeness, apply gentle pressure to plums with fingers. If the skin feels soft and takes on a dusty appearance, the plum is ready to be picked.  The fruit should easily separate from the branch.

  • Storage:

    Plums do not last long after harvesting. They should be washed and eaten quickly, or refrigerated immediately (in an open plastic bag or egg carton) after picking. Plums stored in the refrigerator crisper will keep for 2 to 4 weeks.

    If plums are somewhat unripe when they are removed from the tree, do not refrigerate. Store at room temperature in a paper bag to ripen.

    Plums can also be frozen or made into preservatives, jams or jellies.

    To freeze, wash and dry plums and then slice into quarters, removing pits. Lay wedges on a cookie sheet and freeze. Once fully frozen, transfer to an airtight storage bag or bin and return to freezer.

    To make plum jam, remove skins and combine flesh with sugar, lemon juice and pectin and store in sterilized jars.

  • History:

    Plums are one of the earliest and most widely cultivated fruits known to humans. The European plum has been traced to the European and Caucasian mountains, while the Japanese plum originated in Asia. Evidence of plums has been found at Neolithic-age human settlements.

    The first record of plums is found in documents dating as far back as 479 BCE, in the writings of Chinese philosopher, Confucius. There is debate about the spread of plums through northern Europe. Some sources state that Alexander the Great is responsible for the spread of plums through the Mediterranean around 330 BCE, from which they spread to the north. Other sources state that plums did not arrive in northern Europe until the Crusades, when they were brought back by Crusaders returning from Jerusalem during the late 12th and early 13th centuries CE.

    Plum pudding was made with dried plums or prunes in medieval England, but by the 16th century, plums were replaced by raisins. Plums or no plums, “plum pudding” retained its name - and was outlawed as “sinfully rich” by the Puritans in England! Plums arrived in North America via the British colonists in the 17th and 18th centuries.

    Today, plums are the second most cultivated fruit on earth, second only to apples.

  • Top Producers:

    China, Serbia, Romania, Turkey and Chile are the world’s top plum-producing countries  (FAOSTAT, 2013).

     

    Rankings change annually due to the alternate-bearing nature of plums, but China maintains its top ranking by more than 5 million tons.

  • Varieties:

    Popular varieties include:

    European: Stanley, Green Gage, Seneca

    Japanese: Satsuma, Methley, Burbank, Ozark Premiere

    Hybrid (American): Alderman, Superior, Underwood

  • Products:

    Plums are eaten fresh, made into jams and jellies, and canned in syrup. They are ingredients in muffins, pies, tarts and other desserts, cocktails, and salads. Plums can be poached or baked in a variety of recipes, and even added as a sweet element to savory dishes.

    Plums are also dried into prunes and often used as a digestive aid in the form of either dried fruit or juice.

  • Top Health Benefits:

    Bite into a plum and enjoy the health benefits of the sweet and juicy “stone fruit” that humans have been enjoying ever since the Stone Age - so yes, it’s Paleo diet-approved.

    Plums have a high antioxidant content, and are noted in particular for their high levels of the phytonutrients, phenol neochlorogenic and chlorogenic acid. These phenols are shown to neutralize dangerous free radicals in the body and prevent oxidative damage to fats (including cell membranes and brain cells).

    Phytonutrients anthocyanin and quercetin found in plums also protect the brain, and are preventative aids against diseases such as Alzheimer’s.

    Plums have good levels of potassium that support heart and blood vessel (blood pressure) health.

    The vitamin C content of plums supports a strong immune system and healthy tissue in the body, and increases iron absorption in the blood stream.

    Vitamin C also helps to prevent cholesterol in the body from being oxidized by free radicals. Cholesterol oxidation causes plaque to develop on the walls of the arteries (atherosclerosis) and damages blood vessels. Vitamin C  is also useful in preventing conditions associated with atherosclerosis, including heart disease and stroke, as well as cancer.

    Plums also help the body regulate cholesterol with their high levels of soluble fiber, which binds bile acids and helps remove them from the body through defecation.

    Plums are an effective aid in battling constipation, particularly in the form of prunes. The fiber in plums provides bulk in the intestine and stimulates digestion, encouraging colon health.  Insoluble fiber in plums is also helpful as it helps to feed “friendly bacteria” that prevent “bad bacteria” from surviving in the digestive tract, and by producing a short-chain fatty acid called butyric acid, which serves as fuel for cells in the large intestine and colon.

    The high soluble fiber content in plums also helps to normalize blood sugar levels and increase insulin sensitivity in type II diabetics.

  • Grow it yourself:

    European and American plum varieties grow in almost any area of the United States. Japanese plum trees are less cold-hardy than other varieties, and should only be grown in USDA hardiness zones 5 to 9 that are not susceptible to long winters and early spring frost.

    It’s best to start with a nursery grown tree as it will produce fruit more quickly for you.

    All varieties of plum trees require fertile, well-draining soil and full sunlight for optimal growth. Plant after the last spring frost.

    Check with a nursery to choose the best plum tree to grow in your region. Note that several types of plum tree require cross-pollination, in which case you need to be prepared to plant multiple trees to successfully grow plums. Alternatively, you can choose a self-pollinating variety that produces fruit on its own. Stanley (European) and Methley (Japanese) are popular self-pollinating plum cultivars.

    Avoid planting plum trees in low-lying areas where frost may settle, and if possible, choose a sheltered area that is protected from wind. This will help the tree set fruit.

    Space standard trees 20 to 25 feet apart. Space dwarf varieties 15 to 20 feet apart.

    Water newly-planted plum trees every week during their first growing season. Afterward, continue watering deeply at the root line, waiting for the soil to dry out (not completely), and re-watering. Continue watering well into October to provide plum trees with plenty of moisture through winter months.

    Do not fertilize young trees until they have produced their first crop. Once trees begin bearing fruit, fertilize year-round with a 10-10-10 fertilizer.

    Rake away dead leaves and debris in fall.

    Prune trees in spring and summer only. Do not prune trees in the fall or winter, or there may be risk of infection or injury.

    Japanese plums require heavy pruning to keep their shape and for optimal fruit production. Prune to create an open center shape by cutting away vigorous shoots from the top of the tree during the first year by two or three buds. The goal is to create three wide-angled branches, spaced equally apart. Check the tree after a month and cut back any other branches to encourage the three main branches. During the following summer, cut back the branches in the middle of the tree to short stubs and prune shoots below the three main branches. Continue removing shoots from the center of the tree to help it maintain its shape. Thin out fruit so that it is spaced 3 to 4 inches apart.

    European plums should be pruned in a central leader pattern, with branches spiraling around the tree every 5 to 8 inches so that no branch is directly above another. Prune from the first year in early summer to remove any shoots within 18 inches of the ground, and train branches in a spiral.

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