When do I prune a plum tree?

June, July, or early August — NEVER in winter. Pruning in dormant season exposes the tree to silver leaf disease (Chondrostereum purpureum), a fungus carried by airborne spores in winter that enters fresh wounds and gradually kills branches. Summer wounds heal quickly and resist silver leaf because the spores aren't around. Light annual pruning in summer is much better than occasional hard winter pruning. Remove dead/diseased/crossing branches first, then thin to improve airflow.

Do I need two plum trees for pollination?

No, if you choose a self-fertile variety. Victoria, Czar, Opal, Marjorie's Seedling all crop without a partner. Self-fertile plums make up most of the popular UK varieties and are the right choice for a single-tree garden. If your plum is not self-fertile (e.g. Coe's Golden Drop, Cambridge Gage), you need a partner from the same flowering group — check at purchase or by variety name.

Why has my plum tree never cropped — or only some years?

Three common causes. (1) Frost on blossom: plums flower very early (March–April) and a late frost kills the crop. South or west-facing sheltered positions help. (2) Biennial bearing: an over-cropping year exhausts the tree and the next year gives almost nothing. Thin heavy crops in June (5–7 cm fruit spacing) to break the cycle. (3) Too young: plums on St Julien A take 4–5 years to crop properly; on Pixy often 3 years; on Brompton 5–7 years.

What are the small dimples and grubs in my unripe plums?

Plum sawfly damage. Sawfly larvae enter developing fruit in June, leaving a small dark dimple; the fruit usually drops to the ground while still small. Damaged fruit shouldn't be eaten (the grubs are inside). Two controls. (1) Pheromone traps for plum moth (and sticky traps for sawfly) hung in trees from late May. (2) Hygiene: pick up and bin all dropped fruit through June–August — the larvae overwinter in the soil and re-emerge next year.

What's the best plum variety for the UK?

Victoria — the safest, most productive, classic UK plum. Self-fertile, heavy cropper, dessert-and-cooking flavour, available everywhere. For colder gardens (Highlands, exposed Midlands): Czar (cooking, very hardy and reliable). For dessert plums: Opal (early), Marjorie's Seedling (late). For gages (sweeter, more aromatic plums): Cambridge Gage (needs a partner) or Oullins Gage (self-fertile).

Can I grow a plum tree in a pot?

Yes — on Pixy rootstock only. A 50 cm pot of peat-free compost, in a sheltered sunny spot. Plum trees in pots need: (1) permanent staking, (2) slow-release fertiliser in April plus monthly liquid feed, (3) consistent watering (drying out causes fruit drop and disease), (4) summer pruning to keep the size manageable. Repot every 3 years in winter, replacing outer compost. Pot plums crop reliably though smaller — useful for patio fruit.

Susino (prugno)

Prunus domestica

Plant plum trees bare-root from November to March, in a sheltered sunny spot in well-drained soil — plums flower very early (March–April), so a frost-protected position is essential or the crop is lost. Plums are hardy (RHS H6) but the early blossom is not. Victoria is the UK's reliable choice — self-fertile, hugely productive, classic flavour, and crops in cooler gardens where other plums struggle. Never prune a plum in winter — pruning when dormant invites silver leaf disease (a fungus that enters open wounds and kills branches); prune in June–August when wounds heal fast. Rootstock controls size: Pixy for small trees and patio culture, St Julien A for half-standards (the UK standard), Brompton for full-size orchard trees. Watch for plum sawfly (worms in young fruit), plum moth, and brown rot in damp summers.

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