How the pollination checker works
Our pollination checker is intended to be used as a guide only, and is by no means 100% accurate, but we regularly update it. Here's how it works.
Pollination of Apples
Compatible apple varieties are selected on the basis of common or overlapping bloom times and flowering groups (1-6) .
Varieties which are known to produce low quantities of pollen or poor quality pollen are excluded.
Varieties which are closely-related (for example, share a common parent) are excluded from the selection because cross-pollination is less effective between close relatives.
Varieties which belong to the same genetic incompatibility group are excluded (even though they may not be closely related to your variety) because cross-pollination will be less successful or may not be possible at all.
The scientific data on the genetic incompatibility between apple cultivars is incomplete, and many other factors affect successful pollination. Our article on the pollination of fruit trees gives more details of some of the factors involved in pollination.
Most white-flowered crab-apples are also good pollinators of apple trees.
Pollination of European pears, Perry pears, and Asian pears
Pears follow broadly the same pattern as apples, with pollination based on bloom times and flowering groups (1-6), with a few enhancements for specific incompatibilities.
Asian and European pears are different species, but their pollen is usually compatible.
Perry pears are European pears, and have similar pollination requirements.
The popular Williams / Bartlett pear is incompatible with a small number of other pear varieties, so these are excluded.
Pollination of European plums, gages, damsons, and mirabelles
All these species are very closely related and are generally compatible, so if they are in flower at the same time they should cross-pollinate.
Note that the same range of pollination groups (1-6) are used for plums, cherry plums, and Japanese plums.
Pollination of Cherry plums
All varieties of this species (Prunus cerasifera) tend to flower at about the same time (in plum flowering group 1) and will cross-pollinate. Many are also partially self-fertile.
Many will cross-pollinate with Japanese plums in flower at the same time.
Pollination of Japanese plums
Japanese plums (Prunus salicina) are generally not compatible with European plums (Prunus domestica) , but will often cross-pollinate
with cherry plums.
Pollination of Cherries
Sweet cherries (Prunus avium) are the only fruit species where pollination can be problematic. Sweet cherries exhibit considerable incompatibility between varieties, and even if two varieties bloom at the same time cross-pollination may not occur. Recent PCR testing has shown that the accuracy of previous research into these "incompatibility groups" is poor.
Because of this uncertainty our pollination checker will only recommend varieties which flower at the same time and are universal pollinators.
Universal pollinator varieties will pollinate all other cherry varieties which are in flower at the same time (with a few exceptions, for example Stella - a universal pollinator - will not pollinate Bing).
If you are just starting out with growing cherry trees you can avoid many of the problems of cherry-pollination by planting self-fertile varieties.
Sour cherries (Prunus cerasus) will pollinate sweet cherries that are in bloom at the same time.
Unfortunately the blossom of ornamental or flowering cherries is hardly ever viable for pollinating sweet or sour cherries.
Pollination of Apricots
Apricots are all reliably self-fertile so cross-pollination is not an issue, but different varieties will cross-pollinate - and they all flower at around the same time.
Pollination of Peaches and Nectarines
Peaches are all reliably self-fertile so cross-pollination is not an issue, but different varieties will cross-pollinate if they are in flower at the same time.
Nectarines are simply peaches with a smooth skin, and will cross-pollinate with other peaches and nectarines in flower at the same time.
Pollination of Hazel trees
Our pollination checker does not yet cover hazel trees, but our article on hazel pollination includes a matrix of compatible varieties.
Pollination of Almond trees
Almond varieties are all reliably self-fertile so cross-pollination is not an issue.
Pollination of Medlar trees
Medlars are all reliably self-fertile so cross-pollination is not an issue.
Pollination of Mulberry trees
Mulberry varieties are all reliably self-fertile so cross-pollination is not an issue.
If the variety you want to know about is not on the list we may still be able to help - just send us an enquiry.