Green, healthy-looking cherries stop growing and fall before they ripen, some years as a scattering and other years as most of the crop. The RHS calls it cherry fruit drop or run off; Pacific Northwest Extension (a US source) calls the same process a normal occurrence that needs no cultural control. A normal process can still take most of the crop in a bad year.
What it looks like
Green fruit that appears to be developing normally stops growing and falls, sometimes turning shades of brown to grey just before it drops. Pacific Northwest Extension describes three waves: the first about two to two-and-a-half weeks after full bloom, a second about a week later, and a smaller third wave about three weeks after the second. The fruit on the ground is small, and the stem is still green.
The cause: weather, energy reserves and the tree sorting its own crop
Poor weather and low light at blossom time are the main triggers named for heavy drop, and fruit yields are lower after wet, cold autumns, when the tree has stored less energy to support early fruit growth. Poor pollination, lack of water while the fruit is developing and other adverse weather are also given as causes of immature fruit being shed. The exact mechanism isn't pinned down: Pacific Northwest Extension lists lack of pollination, lack of fertilisation, incompatibility, nutrient imbalance, winter injury, frost around bloom and high temperatures during bloom as possibilities. Some cultivarsA plant variety that arose or was bred under cultivation and is kept true by deliberate propagation, rather than a naturally occurring wild species. Full definition →, 'Sweetheart' among them, shed more than others, and some rootstocksThe root system and lower stem a fruit tree is grafted onto, chosen to control the tree's eventual size rather than for its own fruit. Full definition → and varieties may be less affected.
The two sources differ on what to do. The RHS offers remedies (pruning, thinning and siting) and says more research is needed on how much fruit to leave. Pacific Northwest Extension says no cultural control is needed because it is a normal occurrence. A normal process can still be severe: in 2000, as much as 90% of the fruit that set on UK sweet cherries was lost before maturity (RHS).
Why this matters in Scotland
Several of the named triggers are weather a Scottish spring can supply: poor weather and low light at blossom time, low temperatures in early fruit development, and frost around bloom. That points to more drop here in a cold, dull spring, though no source gives Scottish figures. Cherry blossom is susceptible to frost damage, which can reduce the crop, so the site and frost protection below matter as much as anything done for drop itself.
What helps
None of these is guaranteed to stop the drop; they work on the conditions it responds to.
Prune for an open canopy that lets in more light
An open canopy maximises light to the leaves, which is likely to minimise drop, and poor light at blossom time is one of the triggers named. Where the problem recurs, consider altering the pruning regime to allow more space between branches.
Thin fruit where there are more than 10 fruitlets per spur, while they are under 5mm across
Thinning reduces the crop load the tree has to support. More than 10 fruitlets per spur is the point at which to thin; beyond that, how many to leave is not yet clear, because more research is needed (RHS).
Grow in a warm, sheltered, sunny spot, against a sunny wall or by a light-coloured path
Choose a warm, sheltered location that isn't prone to late frosts. Sweet cherries need sun, such as a south or south-west facing wall, and pale woodchip beneath the tree reflects light back up.
Choose self-fertileA plant that can set fruit using its own pollen, without needing a second, different variety nearby to cross-pollinate it. Full definition → varieties, or plant a pollination partnerA second, different variety of the same fruit planted nearby so the two can cross-pollinate each other, needed by any variety that isn't self-fertile. Full definition →
Poor pollination is named as a cause of immature fruit being shed. Many modern varieties are self-fertile, so one tree gives a good crop, and acid cherries are self-fertile too, but even self-fertile trees usually crop better with a pollination partner nearby.
Water newly planted trees in dry spells
Lack of water while the fruit is developing is named as a cause of immature fruit being shed. Newly planted cherry trees should be watered during dry spells for at least the first year; established trees in open ground shouldn't need watering, and trees in containers need steady moisture.
Cover small trees overnight when frost is forecast at blossom time
Cherry blossom is susceptible to frost damage, which can reduce the crop. Cover small trees overnight when frost is forecast, then remove the cover during the day so pollinating insects can reach the flowers.
Myths about cherry fruit drop
“Poor pollination, or the lack of a compatible pollinator partner tree, is the reason cherries drop off before ripening.”
Pacific Northwest Extension lists lack of pollination alongside lack of fertilization, self-incompatibility, nutrient imbalance, winter injury, frost damage and high bloom-time temperatures as possible explanations for June dropA tree's natural shedding of some immature fruit in early summer, thinning its own crop rather than a sign of a problem. Full definition →, then states outright that the exact mechanism is unknown. The RHS attributes drop to poor weather and low light at blossom time and reduced energy reserves after a wet, cold autumn, while its cherry growing page gives poor pollination, lack of water and adverse weather as causes of immature fruit being shed.
Our read This claim also mixes up two different problems. A poorly pollinated flower typically fails to set fruit in the first place rather than setting a fruitlet that then drops weeks later, which is part of why Pacific Northwest Extension flags pollination only as an untested candidate rather than a confirmed cause. Choosing a compatible pollinator variety is necessary for many sweet cherries to set fruit at all, but that is a separate fruit-set question from why already-forming fruitlets subsequently drop.
What to do: Plant a compatible pollinator variety, or a self-fertile cultivar, to make sure flowers set fruit in the first place. Do not assume a pollination fix will stop fruitlets that have already set from later dropping; treat that as a separate, less understood problem.
2 sources
- Pacific Northwest Pest Management Handbooks: Cherry (Prunus spp.) - June DropLack of pollination is one of several possible explanations listed for June drop, alongside lack of fertilization, incompatibility, nutrient imbalance, winter injury, frost damage around bloom and high bloom-time temperatures, but the exact mechanism is unknown.
- RHS: Cherry fruit dropThe growing guide gives poor pollination, lack of water when fruits are developing and adverse weather as causes of immature fruit being shed.
“Keeping a cherry tree well watered while the fruit is developing prevents fruit drop.”
The RHS names lack of water while the fruit is developing as one cause of immature fruit being shed, and advises watering newly planted trees in dry spells for at least the first year, while established trees in open ground shouldn't need watering. No source tests watering as a way to prevent fruit drop, and Pacific Northwest Extension does not list water among its candidate mechanisms.
Our read Watering a young or drought-stressed tree in a dry spell is reasonable care, but no source shows that watering prevents this kind of fruit drop, so the claim is unproven.
What to do: Water a newly planted cherry tree in dry spells as routine care, but don't treat it as a proven cure for fruit drop; the RHS options are pruning for more light, thinning fruitlets under 5mm, and siting the tree somewhere warm, sheltered and sunny.
2 sources
- RHS: How to grow cherriesLack of water during fruit development is named as a cause of immature fruit being shed; newly planted trees should be watered during dry spells for at least the first year.
- Pacific Northwest Pest Management Handbooks: Cherry (Prunus spp.) - June DropThe page lists pollination, fertilization, incompatibility, nutrient imbalance, winter injury, frost and heat at bloom as candidate mechanisms; water stress or irrigation is not among them.
“Feeding a cherry tree extra fertiliser stops it dropping fruit.”
Nutrient imbalance appears only as one of several unconfirmed candidate mechanisms on Pacific Northwest Extension's page, alongside pollination, self-incompatibility, winter injury, frost and bloom-time heat, with the exact mechanism stated as unknown. That same source's guidance for growers is explicit: no cultural control is needed because June drop is a normal occurrence, and fertiliser is not offered as a remedy. The RHS remedies are pruning for more light, thinning fruitlets, and growing against a sunny wall or by a light-coloured path; feeding is not among them.
Our read Fertiliser is not shown to prevent drop and is not offered as a remedy, so skipping it costs nothing; the pruning and thinning advice is the part that is on record.
What to do: Skip extra feeding as a fix for fruit drop. Prune for an open, light-filled canopy, thin fruitlets while still under 5mm across, and grow the tree in a warm, sheltered, sunny spot.
2 sources
- Pacific Northwest Pest Management Handbooks: Cherry (Prunus spp.) - June DropLack of fertilization and nutrient imbalance are listed only as unconfirmed candidate mechanisms, and the page states no cultural control is needed since June drop is a normal occurrence.
- RHS: Cherry fruit dropThe remedies given are pruning to an open canopy, thinning fruitlets under 5mm across and growing against a sunny wall or by a light-coloured path; fertiliser is not among them.
“A wave of green cherries falling off the tree in early summer is a normal thinning process, not a sign the tree is diseased or failing.”
Both a UK and a US source treat this as ordinary tree behaviour rather than a disorder to cure. Many fruit trees naturally shed some immature fruit in early summer, with a good crop usually remaining on the tree (RHS). Pacific Northwest Extension defines the phenomenon as the normal abscission of fruits before pit hardening and considers it a normal occurrence needing no cultural control.
Our read The two sources still disagree on how much attention a bad year deserves. In 2000 as much as 90 percent of set fruit was lost before maturity in the UK (RHS), which is well beyond gentle thinning. A single tree dropping a modest scatter of small, green, immature fruit shortly after bloom fits the normal pattern both sources describe; a tree stripped nearly bare does not, and is worth investigating for the weather and pollination factors rather than dismissing.
What to do: Ignore a light scatter of small, green, immature fruit dropping in the weeks after bloom. Only start troubleshooting if the losses look severe compared with what set initially.
2 sources
- RHS: Cherry fruit dropMany fruit trees naturally shed some of their immature fruits in early summer and this is not generally a cause for concern, as a good crop usually remains on the tree.
- Pacific Northwest Pest Management Handbooks: Cherry (Prunus spp.) - June DropJune drop is the normal abscission of fruits that occurs before pit hardening; it is considered a normal occurrence and no cultural control is needed.
Frequently asked questions
Is my cherry tree diseased if fruit keeps falling off?
Almost certainly not. Many fruit trees naturally shed some immature fruit in early summer, and a good crop usually remains. A severe year does happen: as much as 90% of the fruit that set on UK sweet cherries was lost before maturity in 2000. A bad year is dramatic, but the process itself is normal rather than a sign of disease.
When does the fruit drop?
Pacific Northwest Extension (US) describes three waves: the first about two to two-and-a-half weeks after full bloom, a second about a week after that, and a smaller third wave about three weeks after the second. The RHS timing is simply summer, before ripening.
Is there a spray or feed that stops it?
No product is named for it by either source. It is a response to weather, light, energy reserves and the tree's own crop load. The steps that are suggested (pruning for light, thinning fruitlets, a sunny sheltered site, watering young trees in dry spells) work on those conditions.
Do all cherry varieties drop fruit the same amount?
No. 'Sweetheart' is named as shedding more fruit than other cultivars, and some cherry rootstocks and varieties may be less affected (RHS). Neither source ranks variety against weather as a cause, so how much variety alone changes things is not clear.
Sources
Show the 3 sources
- RHS (cherry fruit drop): the 90% loss in 2000, poor weather and low light at blossom, lower yields after wet cold autumns, pruning for an open canopy, thinning above 10 fruitlets per spur and under 5mm, sunny wall or light-coloured path, more research needed, some rootstocks and varieties less affected
- RHS (growing cherries): poor pollination, lack of water and adverse weather as causes of immature fruit being shed; watering newly planted trees; frost damage to blossom and covering overnight; a warm, sheltered site
- Pacific Northwest Extension (US): a US source: the same process under the 'Cherry Run Off' name in Europe, the three-wave drop timing, the symptoms of dropping fruit, 'Sweetheart' shedding more than other cultivars, the list of possible mechanisms, and the no-cultural-control-needed stance