Fruit Tree Pollination Checker

Find out whether a variety sets fruit on its own, how many partners it needs, and which varieties actually work — with the incompatible ones named, and the reason given.

How fruit tree pollination actually works

Most fruit trees cannot fertilise themselves. Apple, pear, sweet cherry and most plum are gametophytically self-incompatible: a tree rejects its own pollen, and the pollen of any variety that shares its incompatibility alleles. Planting a single variety, or two varieties that happen to be related, produces flowers every spring and very little fruit.

Getting this right at planting matters more than almost any other decision, because it is the one you cannot correct cheaply. Spacing can be thinned, irrigation retrofitted, training changed. A block of mutually sterile varieties has to be grafted over or replanted, and you will not know for three to eight years.

What this checker is built on

Compatibility here is computed, not looked up in a list of recommended pairs. For cherry, the tool stores each variety’s two S-alleles and derives the answer: no allele shared means fully compatible, one shared means semi-compatible, both shared means blocked. A hand-written list of good pairs is always incomplete, and it is incomplete in the direction that hurts — it silently omits the exclusions.

113: varieties with reviewed pomology
22: with a published S-genotype
32: that set fruit unpartnered
6: triploids needing two partners
9: that never donate pollen
2: that set fruit without pollen

Records are transcribed from commissioned pomologist reviews, with the source recorded per claim. Where a figure could not be attributed it was left out rather than estimated.

The three mistakes that cost a crop

01
Assuming different varieties means compatible varieties
Incompatibility groups cut across appearance, era and origin. Van is an old mid-season cherry and Regina a modern late one; they look and behave nothing alike, are both widely planted, and cannot pollinate each other.
02
Treating a triploid as an ordinary partner
A triploid's pollen is sterile. It cannot reciprocate, so the variety planted to serve it is left without a pollen source of its own. Triploids need two diploid partners, not one.
03
Trusting a nursery's self-fertile label
No commercial apple variety is genuinely self-fertile. Some set a reduced crop alone in hot, reliable-bloom climates and fail to in cool maritime ones — a climate-dependent behaviour, not a genetic property, and not a substitute for a partner.

Common questions

What does self-fertile actually mean?: A self-fertile variety sets a commercial crop with its own pollen, so a solid block of it will fruit. Self-sterile varieties will not — they need a different variety flowering at the same time, close enough for bees to move between them. Many varieties sold as self-fertile still set a materially heavier crop with a partner nearby.
Why does a triploid variety need two pollination partners?: A triploid produces sterile pollen. It cannot fertilise anything, including the partner planted for it — so that partner has no pollen source of its own and will itself crop poorly. Two compatible diploid partners solve it: they pollinate the triploid and each other. Bramley's Seedling, Jonagold and Blenheim Orange are all triploid.
Do two different varieties always pollinate each other?: No, and this is the error that costs whole blocks. Sweet cherries are assigned to incompatibility groups by S-genotype, and every member of a group is mutually sterile regardless of how different the varieties look. Bing, Lambert, Napoleon and Emperor Francis were the four dominant North American cultivars for most of the twentieth century and are completely mutually sterile — blocks planted assuming four varieties meant adequate pollination failed outright.
Can a variety be a partner for one tree but not another?: Yes. Compatibility is a property of the pair, not of either variety alone. Two varieties that share one S-allele are semi-compatible: only half the pollen is functional. Those pairings are commercially dominant — Bing with Rainier in the Pacific Northwest, Kordia with Regina in Europe — but they need higher hive density and a second fully compatible partner to be safe in a poor bloom.
Why does the checker sometimes refuse to name a partner?: Because the data does not support one. Where a variety's genotype or pollination group is not established in a source we can cite, the tool says nothing rather than guessing. A wrong partner is not a minor error — it costs a crop and takes three to eight years to discover. Silence is the correct failure mode.
Can a crab apple pollinate my apple trees?: Often yes, and commercially it is standard practice. Crab apples flower over a long window and produce abundant compatible pollen, which is why varieties like Dolgo are planted as dedicated pollinizers. They also occupy space that would otherwise grow a saleable crop, so most commercial blocks use a second saleable variety instead.

Planning the whole block, not just the pollination?

The orchard layout planner takes your block dimensions, rootstock and machinery width and returns a to-scale row layout, an exact tree count including pollinizers, and what the planting costs to establish before it pays back. Same pollination engine, applied to a real block.

How fruit tree pollination actually works

What this checker is built on

113

varieties with reviewed pomology

with a published S-genotype

that set fruit unpartnered

triploids needing two partners

that never donate pollen

that set fruit without pollen

Records are transcribed from commissioned pomologist reviews, with the source recorded per claim. Where a figure could not be attributed it was left out rather than estimated.

The three mistakes that cost a crop

Assuming different varieties means compatible varieties

Incompatibility groups cut across appearance, era and origin. Van is an old mid-season cherry and Regina a modern late one; they look and behave nothing alike, are both widely planted, and cannot pollinate each other.

Treating a triploid as an ordinary partner

A triploid's pollen is sterile. It cannot reciprocate, so the variety planted to serve it is left without a pollen source of its own. Triploids need two diploid partners, not one.

Trusting a nursery's self-fertile label

No commercial apple variety is genuinely self-fertile. Some set a reduced crop alone in hot, reliable-bloom climates and fail to in cool maritime ones — a climate-dependent behaviour, not a genetic property, and not a substitute for a partner.

Common questions

What does self-fertile actually mean?

A self-fertile variety sets a commercial crop with its own pollen, so a solid block of it will fruit. Self-sterile varieties will not — they need a different variety flowering at the same time, close enough for bees to move between them. Many varieties sold as self-fertile still set a materially heavier crop with a partner nearby.

Why does a triploid variety need two pollination partners?

A triploid produces sterile pollen. It cannot fertilise anything, including the partner planted for it — so that partner has no pollen source of its own and will itself crop poorly. Two compatible diploid partners solve it: they pollinate the triploid and each other. Bramley's Seedling, Jonagold and Blenheim Orange are all triploid.

Do two different varieties always pollinate each other?

No, and this is the error that costs whole blocks. Sweet cherries are assigned to incompatibility groups by S-genotype, and every member of a group is mutually sterile regardless of how different the varieties look. Bing, Lambert, Napoleon and Emperor Francis were the four dominant North American cultivars for most of the twentieth century and are completely mutually sterile — blocks planted assuming four varieties meant adequate pollination failed outright.

Can a variety be a partner for one tree but not another?

Yes. Compatibility is a property of the pair, not of either variety alone. Two varieties that share one S-allele are semi-compatible: only half the pollen is functional. Those pairings are commercially dominant — Bing with Rainier in the Pacific Northwest, Kordia with Regina in Europe — but they need higher hive density and a second fully compatible partner to be safe in a poor bloom.

Why does the checker sometimes refuse to name a partner?

Because the data does not support one. Where a variety's genotype or pollination group is not established in a source we can cite, the tool says nothing rather than guessing. A wrong partner is not a minor error — it costs a crop and takes three to eight years to discover. Silence is the correct failure mode.

Can a crab apple pollinate my apple trees?

Often yes, and commercially it is standard practice. Crab apples flower over a long window and produce abundant compatible pollen, which is why varieties like Dolgo are planted as dedicated pollinizers. They also occupy space that would otherwise grow a saleable crop, so most commercial blocks use a second saleable variety instead.