GrowingHQ

Plum: fruit splitting or cracking

2 causes GrowingHQ holds specifically for plum, what separates them, and what is safe to do before you are sure.

What you are looking at

Fruit opening along a seam or across the skin, usually close to ripening. What matters is not the split but what is inside it: a clean fresh crack after rain is a water event and the fruit is still worth picking, while a split that has gone brown, soft or furry is a rot that will spread to the fruit touching it.

Described view

Two ripening plums on the branch at the same scale: one split along a clean fresh crack with firm bright flesh visible inside, and one collapsing into brown rot with buff-coloured pustules in concentric rings around the point of entry and the skin dull and slumped

What it is likely to be on plum

  1. Brown rot

    Candidate 1common on this plant
    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Brown rot

    Checked 2026-08-13

    Fruit turning brown and soft with concentric rings of buff pustules, often while still hanging. Affected fruit shrivels into a hard 'mummy' that stays on the tree over winter and infects next year's crop from where it hangs.

    Points towards it

    • · it spreads between fruit that are touching, so it appears in clusters
    • · the buff pustules form in rings on the rotting surface

    Argues against it

    • · damage spread evenly over the whole tree in one night is weather, not a fungus

    Check this next

    Look at what the split fruit is touching. Brown rot moves from fruit to fruit by contact, so it appears in clusters with a mummified one at the centre — a weather split is scattered wherever the fruit happened to be ripest, and the flesh at the edge of the crack stays firm and pale.

    What to do now

    Remove every rotting and mummified fruit, including the shrivelled ones still hanging in winter, and dispose of them away from the tree. Those mummies are where the fungus overwinters, so clearing them does more than anything else available to a home grower — and thinning the crop so fruit does not touch removes the route it spreads by.

    source

    Sourced guidancehigh confidence

    • Royal Horticultural Society: Brown rot — control

    Checked 2026-08-13

  2. Fruit splitting

    Candidate 2common on this plant
    source

    Sourced guidancemoderate confidence

    • Royal Horticultural Society: Plum — problems

    Checked 2026-08-13

    Fruit splitting open on the plant, usually after rain following a dry spell. Nothing is attacking it: the inside has taken up water faster than the skin can grow, and the skin gives way. The split then lets brown rot in, which is where the real loss comes from.

    Points towards it

    • · a dry spell followed by heavy rain swells the fruit faster than the skin can follow
    • · the swing between dry and wet is a weather event

    Argues against it

    • · a plum splits when dry ground is suddenly wetted; ground that is still bone dry has not delivered the water that does it — this rules it out entirely.

    Check this next

    Ask what the ground did rather than what the fruit looks like. Plums split along the suture after a dry fortnight ends in heavy rain, and the split is clean with sound flesh either side — unlike cherries, which split from water taken in through the skin rather than up from the roots, so a plum on ground that never dried out rarely does it.

    What to do now

    Pick and use the split fruit, and thin the crop earlier next year — a plum carrying too much sets small tightly packed fruit that splits and then rots where the pieces touch. Mulching to keep the soil moisture even through summer does more than watering heavily once the cracks appear.

    source

    Sourced guidancemoderate confidence

    • Royal Horticultural Society: Plum — thinning

    Checked 2026-08-13

Narrow it down

This page lists everything at once, which is the right shape for reading and the wrong shape for deciding. The interactive tool asks one question at a time, starting with whichever would separate these causes fastest, and stops as soon as further answers would not help.

Work through it for your plum

Opens with the plant and the symptom already set. Nothing you answer is stored or sent anywhere — the answers live in the address bar and nowhere else.

What this does not cover

These are the causes GrowingHQ holds rules for on plum — not every cause there is. Where several problems look alike, the honest answer is often that they cannot be told apart by eye, and a page that named one would be guessing. If none of the above fits, the general fruit splitting or cracking page lists causes across all plants, and the Plum profile lists the problems it is prone to.