Plant very firmly. Dig a hole 3 ft. square and about 6 in. deep and spread the roots out evenly in the hole, cutting back cleanly any damaged ones. Put back theand ram it down well.
Plant bush plums 15 ft. square, half-standard plums 18 ft. square and standard plums 2-1/2 ft. square.
Planting should be done in November if possible while the soil is still warm, but may continue, if necessary, to the end of February. Stake the trees while planting so that they cannot move in the winter winds, otherwise what is known as ‘wind-rocking death’ may occur.
Plums need well-manured soil and benefit from a 1-ft. deep mulch of straw. If this is not possible in a small garden, use peat or leaf mould 2 in. deep. In addition, give a yearly dressing of hoof and horn meal ormanure at 4 to 5 oz. per sq. yd. each February. Old cow or pig manure if available is a good alternative mulch, and no additional fertilizer will be needed.
Plums on the whole prefer to grow on cultivated land, but will grow on grass if it is fed with hoof and horn meal in February and again after the plums have been picked. If the leaves turn yellow, apply seaweed meal at the rate of 3 or 4 oz. per sq. yd.
There are only a few self-fertile kinds of plum, so suitable pollinators should be planted .
Prune back the one-year-old growths, known as leaders, by about half their length in the February after planting. Such hardof the leaders is necessary for three years with the strong-growing varieties on vigorous stocks, but must be continued for four years in the case of heavy-cropping varieties on weak stocks. Once good, strong branches have been formed, a tree grown in the open may be left to grow more or less as it will. A certain amount of thinning out to let in light and air will be necessary and this is best done in the summer months when ‘gumming’ quickly seals the wounds against the entry of silver leaf . With spreading varieties such as Victoria and Early Laxton, prune the leaders to an upward-pointing bud, but upright-growing varieties such as President and Czar should be cut back to just above an outward-pointing growth to encourage horizontal growth.
Any big cuts that have to be made in the winter should be smoothed over with a sharp knife and painted with thick white lead paint to prevent the entry of silver leaf disease.
Plum trees that are to be grown in pyramid shape are planted 10 ft. square. Cut back the laterals late in July to 8 in. and allow the central leader to grow upward. Do no winter pruning, with the exception of cutting back one-year-old growth in the last week of March, a few months after planting.
As plums often get bark-bound in April, when the sap is rising, make a vertical slit with a sharp knife from the top of the trunk to the bottom on the north side of the tree. This slitting of the bark eases the tension, helps the tree to grow better, and makes it, some claim, less susceptible to silver leaf disease.
If for any reason the soil beneath the plum trees has to be sown with grass, it is best to use a mixture of Timothy S/50 grass, wild white clover S/184 and extra late red clover S/123, in a ratio of 1: 3: 2. Sow at the rate of l oz. per sq. yd. And lightly rake in. The clovers will give nitrogen to the plums and the sward will look attractive if mown regularly.
When the plums are the size of acorns, thin them out to 3 in. apart. This helps to prevent branch breakages by reducing the weight of fruit, as well as ensuring regular cropping. If there is a heavy crop, even after thinning, support the branches with poles or posts in late June.
RECOMMENDED VARIETIES OF PLUMS AND GAGES
D=Dessert C = Cooking
Bryanston Gage (D), mid-September. Greengage-like, spotted red. Pollinator Greengage.
Cambridge Gage (D), end August. Round greenish-yellow, very delicious. Crops regularly. Pollinator Victoria.
Coe’s Golden Drop (D), mid-September. Yellow with red spots on sunny side. Apricot flavour. Grows on wall. Pollinator Early l.axton.
Czar (c), early August. Large dark purple-reddish. Heavy cropper. Self-fertile.
Denniston’s Superb, (D), mid-August. Sweet greengage flavour. Vigorous grower. Self-fertile.
Early l.axton (D), end July. Oval-shaped yellow, with pinkish flush. Useful for small garden. Pollinator Victoria.
Early Transparent Gage (D), mid-August. Pale yellow with red dots. Heavy cropper. Very delicious. Self-fertile.
Giant Prune (c), mid-September. Large oval, vermilion-red. Rust-resistant. Good for small gardens. Self-fertile.
Green Gage(u),end August. Yellowish-green with russet dots. Uncertain cropper, but delicious. Pollinator Marjorie’s Seedling.
Jefferson (D), end September. Yellowish-green fruit with bronze marks and pink flush. A gage type. Upright grower. Pollinator Denniston’s Superb.
Kirke’s Blue (D), mid-September. Dark purple with violet bloom. Best grown on wall as fan. Pollinator Victoria.
Laxton’s Gage (D), end August. Yellow, round. Vigorous grower. Self-fertile.
Laxton’s Goldfinch (D), end August. Yellow, round, sweet. Good for south wall. Probably self-fertile.
Marjorie’s Seedling (c), end September. Purple, oval, with bluish bloom. Fruit can be left on tree till mid-October. Self-fertile.
Oullin’s Golden Gage (c), mid-August. Large golden-yellow with greyish bloom. Upright grower. Slow to crop. Self-fertile.
President (D), late September. Oval, deep purple with slight blue bloom. Pollinator Denniston’s Superb.
Purple Pershore (c), mid-August. Egg-shaped purple. Flowers well after frosts. Self-fertile.
Rivers’ Early Prolific (c), end July. Smallish purple, with lavender bloom. Weak growing, compact tree. Pollinator Early Laxton. Good for jam-making.
Victoria (D), end August. Carmine with pale blue bloom. Very popular. Branches break easily. Susceptible to silver leaf. Self-fertile.
Yellow Egg (c), end August. Smallish, bright yellow. Very heavy cropper. Self-fertile. Delicious for jam-making.
RECOMMENDED VARIETIES OF DAMSONS
Damsons are small fruits and seem full of stones, and so are less popular than other types of plum. All the varieties listed can be cooked.
Bradley’s King, mid-September. Reddish-purple, oval shaped.
Common Damson, end September. Round, black, in clusters.
Farleigh, mid-September. Round, almost black, slightly tapering.
Merryweather, September. Round, deep blue with heavy bloom. The best garden variety.
Shropshire Prune, late September. Deep purple with dense bloom. Excellent for bottling or canning.
LESS COMMON TYPES OF PLUM
Black Bullaces: Ripe in October.
Bullaces: Tiny plums, smaller than damsons. Often called wild plums. All fruits are bluish-black with purplish bloom, and ripen in autumn.
Cape Plums: Should be grown on a south wall, because they are tender andare often damaged by frost.
Cherry Plums: These are somewhat like cherries but slightly larger, and usually raised from stones. They are picked in July.
There are no particular named varieties in Great Britain.
Shiros: Golden-yellow, oval-shaped plums with white flesh.
RECOMMENED VARIETIES OF JAPANESE PLUMS
Japanese plum trees are hardy in the open only in the south-west of England, but in the Midlands and the south can be successfully grown against a south wall as fan-shaped trees.
They crop heavily and look beautiful when growing.
The fruits, though not large, are decorative and juicy.
Grow, train and prune as for ordinary plums, and spray with a tar oil wash each December to keep away aphids in the summer.
Abundance, August. Round, transparent orange fruit, mottled crimson.
Botan, July. Round, red fruit, very sweet. Moderate grower.
Shiro, August. Golden-yellow, oval fruit. Flesh almost white. Bears the largest fruits of the three.