PLUMS (prunus domestica)
If you choose the right variety, plums are one of the most rewarding fruits to grow, virtually anywhere in the UK. Because you pick them when they are really ripe, they taste better than those in the Supermarkets. Make sure that you check the rootstock before you buy for eventual size, as plums can grow into very big trees. Self-fertile trees are easier to manage as no second tree is required for pollination.
Different varieties mature at different times. If you have room to grow more than one variety of plum, it makes sense to have an early maturing one and a later maturing one.
Plums are very early to flower in the Spring when there may be very few bees about to do the necessary pollination. You may want to help nature along by doing some hand pollination with a soft artist’s brush. Because they flower so early, the flowers can be prone to frost damage in cold exposed areas, or frost pockets. In such cases, better results would be obtained if you grew the plums up against a wall or fence.
Thinning of the plums may well be necessary if there has been a very heavy set of fruit. It will help to prevent the spread of disease and the breaking of branches, because they are carrying such a heavy load. With a pair of scissors, remove any plums that are touching each other.
Do not prune in Winter due to the danger of silver leaf infection.
Summer pruning. In June or July, cut back the new growth by at least half, to encourage the formation of fruiting buds for the following year. In addition, it will help to produce a more sturdy framework of branches to reduce the danger of the branches braking under the weight of fruit.
Autumn pruning. Immediately after gathering in all the plums, remove any diseased, broken, damaged or crossing branches, and thin out branches if they become too crowded. Consider the total size of the tree, when you are carrying out the pruning. There is no point in letting the tree grow too tall for you to easily gather the fruit at harvest time, or to remove split, damaged or rotten fruit during the growing season. It is no joke perching on the top of a high stepladder picking fruit! Remember to paint any cut branches with a propriety “sealing solution” to prevent disease spores gaining entrance.
Root pruning. If the Plum tree is still not fruiting well after say 2 or 3 years, it could be that the ground is too fertile, if you have been overgenerous with manure or fertilizer. Root pruning can be effective in shocking the tree into thinking that the end is nigh, and rush to reproduce with flowers and fruit. Just take a spade and shove it into the ground as far as it will go, in a complete circle about 1 m from the trunk. This cuts off a lot of the surface feeding roots and leaves the tap roots for moisture and anchoring intact.
Fertilizer. Bearing in mind the previous paragraph, only use a slow release fertilizer, such as bonemeal, if the tree does not look healthy.
Pests and diseases.
The Plum Sawfly lays its egg in the embryonic plum at flowering time.The cream/white larvae burrow into the young plum causing it to distort and elongate and fall to the ground early. Remove damaged fruit from the tree as well as any that have fallen and destroy them.
The larvae form a cocoon and over winter in the top 5 cm of soil, ready to pupate at the plum flowering time, allowing the females to start laying their eggs again. In late Winter, cultivate the top 5 cm of soil under the plum tree to allow the birds to seek out and eat the larvae.
Brown rot can lead to the rotting of individual plums, just as they are almost ready. It is probably caused by a fungus gaining access to a damaged plum. The affected plum must be removed as soon as possible to prevent the rot spreading to the adjacent plums.
Wasps are a problem, best dealt with by trapping them. It helps to remove any split or damaged plums, especially in wet weather. Unfortunately, wasps will attack plums long before they are ripe enough to eat. For a small tree, or a group of branches, you could try constructing a mesh envelope from a mosquito net or an anti-carrot fly net, as shown on the adjoining photo’s. You can roll up the edges and seal them with spring clothes pegs. This also allows you to get back in to pick the fruit.
The fruit are at their sweetest and ready to pick when they are well coloured and have a slight “give” when gently squeezed between finger and thumb. As the fruit on a tree ripen at different times, you really have to pick every two days to ensure that they are at their best. Take the opportunity at the same time to remove any damaged or rotten fruit.
The fruit can split if there is a lot of rainfall during the final stage of ripening of the fruit. Remove any split fruit to prevent wasp damage, and use immediately.
Some people pick their plums when they are well coloured but still hard, and finish off the ripening in boxes hidden under the bed, but I have not tried this myself!!
Plums are best eaten fresh, with the juice dripping from your mouth and fingers!! They can also be used in pies, tarts, crumbles, ice cream and jam. See the relevant section.
Storage of plums is a bit of a problem, as they produce so much fruit in a short time. They can be stored for several weeks in an open container in the bottom of the fridge and taken out and used as fresh. One of my all time favourite methods is to store them covered with a cheap spirit such as vodka, rum or brandy, in large 2.5 Lt glass bottling jars with wide lids. They will keep over the Winter this way and you can use them as necessary, say on your morning porridge. Mmmm!! See Wine and Liqueurs. Bottling them is also a good method for long term storage.
Suggested varieties. I really do not see the point in growing a variety of plum that is only suitable for culinary use. Far better to choose a sweet, fresh eating plum, which can also be used for cooking purposes.
Avalon. This is a large, sweet, juicy, early plum which came top in an independent taste test. Slightly chewy skins but it is a freestone plum. Flowers April. Harvest mid August in the South UK, partially self-fertile but better if other plums, such as Victoria, and gages are close by. Available on Pixy, St Julien A, VVA-1 (Krimsk 1), rootstocks.
Burbank’s Tangerine. This is a sweet, juicy plum with some acidity and chewy skins which was well rated in an independent taste test. Flowers April. The harvest is in late September, so probably not suitable for the North. It is not self-fertile, so you need other plums to flowering in April to pollinate it.
Haganta. This is a large, sweet, juicy, aromatic plum with slightly chewy skins and a free stone. Flowers April. Harvest late September/ October, so probably not suitable for the North. Partially self-fertile, so best with other plums that flower at the same time. Well rated in an independent taste test.
Victoria. This is a luscious eating plum, reliable and high yielding. Also excellent cooked. Flowers April. Ripens August in the South to September in the North. I have found it extremely reliable grown as a tree on an open, north-facing allotment in Glasgow. Self-fertile. Free stone.
Oulin golden gage. An early sweet eating plum, ripening July / August.
Rootstocks for plums. Plums are grafted onto rootstocks to control the vigour and size of the plum tree. For ease of picking the fruit, in most garden or allotment situations, consider VVA 1 or Pixy.
VVA 1, also known as Krimsk 1, best in a fertile well drained soil, grows up to 2.5 m with bigger fruit than if grown on Pixy.
Pixy is used for plums growing to 3 m tall, needs a fertile soil and should start fruiting in 3 years.
St. Julian A for trees from 3-5 m tall, suitable for poor or dry soils, but the tree may take up to 4 or 5 years.
Myrobalan B for trees up to 10 m tall.
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