🌳 Plum tree

Plant in deep, fertile soil that retains moisture but is well drained. Plums generally tolerate heavier clay soils better than many other stone fruits if drainage is improved (avoid waterlogged or compacted sites). Incorporate well-decomposed organic matter before planting and maintain an organic mulch to conserve moisture and improve soil structure. Best performance is generally achieved on slightly acidic to neutral soils (around pH 6-7), although many plum trees will tolerate slightly alkaline conditions if drainage is good.

Plum trees (Prunus spp., commonly P. domestica and related plums) are normally propagated by grafting or budding onto selected rootstocks; plants from seed are mainly used for breeding or as potential rootstocks and are generally not true to parent. When growing from seed (kernels): - Use fresh, ripe kernels. Remove all flesh from the fruit and rinse well to reduce mould. - Cold stratify to break dormancy: place kernels (or extracted almonds) in a moist, sterile medium (e.g. damp sand/vermiculite) in an airtight container at a temperature of approx. 1-5°C for approx. 8-12+ weeks. Check periodically for moisture and mold. - Sowing options : - Outdoors: sow cleaned stones in autumn to benefit from natural winter cooling. - Indoors/containers: after stratification, sow in late winter/early spring. - Sow at a depth of 2 to 5 cm in draining compost/soil, maintain regular humidity (not soggy) and protect from rodents. Germination can be slow and uneven, taking weeks or months. - Grow seedlings for at least one season, then transplant them during the dormant period. Plant a tree (recommended for fruit quality): - Buy a grafted tree suited to your climate and pollination needs. - Plant during the dormant period (late autumn to early spring, when the ground is passable). - Location: full sun; shelter from strong winds; avoid frost pockets; choose well-drained soil (avoid waterlogging). - Planting: plant the tree at the same depth as in the nursery; keep the grafting point above ground level. Tamp, water abundantly and mulch (do not mulch the trunk). Prick if necessary. - Aftercare: water during establishment (especially during dry spells), control weeds and grass around the base, and protect young trunks from rabbits and deer, as well as from sunburn where appropriate.

Base fertilization on soil analysis (and leaf analysis if available) to avoid over-fertilization, especially of nitrogen. - When planting: Do not put fertilizer in the planting hole. If you wish, use well-decomposed compost as a surface mulch after planting. - Non-productive young trees (years 1-3): Apply a light nitrogen program in early spring, when growth begins. Use a balanced fertilizer (e.g. 10-10-10) or nitrogen source, aiming for moderate shoot growth; reduce rates if growth is already vigorous. - Bearing trees: Fertilize mainly in early spring (from bud swelling to flowering). Many plum trees need only a moderate amount of nitrogen; excess nitrogen encourages strong vegetative growth, reduces fruit quality and can increase disease problems. A typical annual target is around 110-225 g of actual nitrogen per mature tree, adjusted to tree vigor, crop load and test results. - Potassium and phosphorus: Apply only if soil and leaf tests indicate a deficiency. Potassium is generally necessary for fruiting and must be corrected in case of deficiency. - Timing precautions: Avoid nitrogen applications in late summer or early autumn, as they can stimulate late growth and increase winter damage. - How to apply: Spread evenly under the canopy to the drip line (and slightly beyond), keeping the fertilizer 15-30 cm from the trunk and watering well. Maintain a layer of organic mulch to improve soil structure, but do not spread it over the trunk. - Monitor and adjust: if shoot growth is excessive and fruiting is weak, reduce nitrogen; if growth is weak and leaves are pale, increase fertilizer slightly and check soil and leaf nutrients again.

Apply an organic mulch (well-decomposed compost, leaf mold, wood shavings or straw) to the root zone to conserve moisture and eliminate weeds. Maintain a layer of 5 to 10 cm (2 to 4 inches), extending from the outside of the trunk to the drip line if possible. Keep the mulch 10-15 cm from the trunk and crown to prevent bark rot, rodent damage and disease. Mulch in spring after the soil has warmed up and/or in autumn to mitigate temperature variations; top up as the mulch decomposes. Water the soil before mulching during dry periods, and avoid very cool, high-nitrogen manures directly against the root zone.

Newly planted plum trees should be staked for the first 1-3 years, especially on dwarf rootstocks, in exposed or windy sites, or where the soil is loose. Use a sturdy stake (wood or metal) driven firmly into undisturbed soil on the windward side, and tie the trunk with a wide, flexible, adjustable tie, with a spacer to prevent bark rubbing. Fasten the tie low on the trunk (approx. 30-60 cm) so that the canopy can move slightly; this movement helps the trunk to strengthen while the root system establishes itself. Check ties at least twice a year and after storms; loosen or reposition them to prevent girdling as the trunk thickens. Remove the stake and ties when the tree is well anchored and no longer swaying at the base (often after 1 to 3 seasons).

Plum fruits (Prunus spp.) - particularly dried plums (prunes) and prune juice - are well known for their contribution to the fight against constipation, thanks to their soluble/insoluble fiber content and sorbitol, which can increase stool frequency and improve consistency. Plums also provide antioxidant polyphenols (e.g. chlorogenic acids) that contribute to antioxidant activity and can support overall cardiometabolic health as part of a balanced diet.

Train plum trees as an open center (vase) or as a modified central leader with 3 to 5 well-spaced scaffolding branches. Prune mainly in summer (midsummer to early autumn, ideally after harvest and in dry weather), as pruning in winter or early spring increases the risk of silver leaf and bacterial canker on Prunus. Young trees (training pruning): - In the first 2-4 years, select scaffolding and eliminate competing main branches, narrow crotch angles and inward-growing shoots. - Slightly shorten overly vigorous new shoots to encourage branching and an open, balanced framework; avoid straight cuts. Established trees (maintenance pruning): - Remove dead, diseased, broken, crossing or twisting branches, as well as branches that grow strongly inward. - Thin out crowded areas to allow light and air to circulate through the canopy; aim to reduce shading rather than "recede" heavily. - Manage vigorous, upright water shoots by removing them at their point of origin or thinning them out; avoid leaving stumps. - If the fruiting wood becomes cumbersome, selectively thin out the density of twigs and branches and renew the older wood by cutting it from a well-placed, outward-facing side. Technical notes: - Make clean cuts just outside the branch collar; avoid large cuts wherever possible. - Do not prune in damp conditions; remove and destroy diseased wood and disinfect tools between suspect cuts.