Plums provide shade and beautiful spring flowers. They are also a delicious snack, whether eaten fresh, stewed, canned, baked or in jams and jellies. There are numerous varieties for home gardeners, but care should be taken to choose the right tree for your region. Some varieties are self-pollinating while others will require another tree to set fruit. Plums usually take five years to bear fruit after planting, so a little care and patience are required.
Plums can be divided into three main categories: European, Damson and Japanese. European plums are best eaten fresh or canned and are best known in cultivation as Stanley, Green Gage and French and German varieties. Damsons are super tart, which makes them most suited for cooking and canning. Shropshire and French Damson are two of this variety. Japanese plums are frost-sensitive and are not suitable in all climates. Japanese plums are grown as Shiro, Ozark Premier, Burbank, Methley and Elephant Heart.
Plums prefer fertile, well-drained soil. It is best to plant a plum tree in late fall or very early spring while it is still dormant. No fertilizer is needed at planting time but a light topping of compost or mulch is beneficial.The planting hole can have some bone meal, which is rich in phosphorus, sprinkled in the bottom. This will give the roots a good start. When planting multiple trees, allow at least 12 feet between them.
Size and Pruning
Plums do not bear off spurs like pears and apples, so they are unsuitable for espaliering or training. They do need regular annual pruning to remove dead wood and keep the tree open. When the trees are dormant it is a good idea to remove excess top growth so you can keep the tree in the stature you need for the garden. This is best done annually as one large topping puts too much stress on the tree. Dwarf plums are available, but the rootstock is still not perfect and there are numerous problems with these trees.
Fertilizer is usually labeled with three numbers. The first number refers to nitrogen, which causes vegetative growth. The second number is phosphorus, which will encourage flowers and fruit. The third number, potassium or potash, will give roots a healthy boost. Ideally, soil analysis can be conducted but when this is not possible a balanced fertilizer can be applied to most plants; a 10-10-10 formula gives good basic nutrition and covers a wide range of plant types.
When to Fertilize
Plums should be fertilized annually after the first year. A rule of thumb is 8 oz. 10-10-10 for each year of tree age. Alternatively, compost or top dress with manure in spring and work in during the fall. Supplement with nitro-chalk and sulphate of potash in February and then every third year add superphosphate. A mulch of manure or compost surrounding the tree, but not touching the trunk, can do a good job of supplying extra nutrients.