Page 35 - Simply Vegetables Spring 2023

The pollination
of fruit trees
GERRY EDWARDS FNVS
I am often asked about pollination when I’m giving talks so I thought that it would make sense to say a few words in these pages.
The first thing to know is that the flowers of the fruit trees that we grow in the UK - apples, pears, apricots, quinces, medlars, cherries, plums, peaches and nectarines
- have both male and female parts and
for a fruit to be created these female parts must receive pollen from the male parts
of another flower - usually from another tree. Generally, this means that you cannot grow a single fruit tree by itself - unless you happen to have another close by in
a neighbour’s garden or the fruit variety that you are growing is self-fertile. The tree which carries the male pollen is known as the pollinator and the process is known
as cross pollination. To ensure successful pollination takes place several rules MUST be followed -
a. Onlytreesofthesametypecan pollinate and receive pollen i.e., only apples can pollinate apples and receive pollination from each other. Apples cannot pollinate pears and vice versa! It always surprises me just how many people think that apples can pollinate pears and so on!
b. Separatevarietiesmustbeinvolved i.e., the apple Discovery cannot pollinate another Discovery but
Lord Lambourne can pollinate Discovery and vice versa and the pear Conference cannot pollinate another
Conference but Doyenne du Comice can pollinate Conference and vice versa
c. Unlessvarietiesknownastriploids (details of these later) are involved it is a two-way process between two trees PROVIDING they are both in flower at the same time
To take pollination on further it should be noted that there are three types of fruit tree to consider -
d. Pollinators-mostfruittreesfallinto this group. They cannot pollinate themselves but will cross-pollinate other trees that are in flower at the same time.
e. Triploids - for genetic reasons, these trees cannot pollinate themselves or other trees. This means that although you only need one other tree to pollinate the triploid, you will need a third tree to cross pollinate with that one because the triploid cannot act as a pollinator.
f. Self-fertile trees - these will pollinate themselves and cross-pollinate other trees that are in flower at the same time. However, a word of warning and help here. Despite contrary claims there are no fully self-fertile apples orpearssoalwaysconsiderapple and pear trees labelled as this to be pollinators only. But with some stone fruits - apricots, cherries, nectarines, peaches, and plums there are some genuine self-fertile trees and those
Apple set
labelled as such and purchased from
a reputable supplier can be trusted. Having noted the above it is very
important therefore to consider flowering times when contemplating planting
fruit trees. Fortunately, help is at hand
as Pollination Tables are available for all types of top fruit. There are seven groups for apples, four groups for pears and five groups for cherries and plums. You are looking for varieties in similar or adjacent groups to plant with each other and act as pollinators. Good books on fruit growing (of which few exist) list these tables and if these are not to hand the internet provides a very valuable source. Such books - which can be obtained second hand were both publishedbytheRHS.Thebestofthese was “The Fruit Garden Displayed” and the other is “Fruit” by Harry Baker.
So how do fruit trees pollinate each other? In all cases in the open this service is undertaken by insects of which the honeybee is probably the best known. Sadly, there are real issues with honeybees at the present time - and I should know as I am a beekeeper (!) - and we are having to rely more and more on other pollinating insects. But you do not have to have hives in your garden to get honeybees onto
your fruit blossoms as they will fly up to three miles from their hives if good flowers
Apple flowers
Apple ‘Golden delicious’
Simply Vegetables 35