Learning about apple tree pollination is important if you wish to maximise output as excellent pollination will produce an abundance of large fruits. For the amatuer grower, learning is uneccessary as your tree will likely still produce fruit, unless it is in an isolated location miles from other apple trees.
Pollination is important as without most apple trees will not produce fruit. Apple trees are just like humans and need to exchange chromosomes to produce offspring (fruit). While there are some apple trees that are self-fertile and will produce fruit without a pollinator, every tree benefits from a partner.
In order for pollination to occur pollen must be transferred from one tree to another. Usually, this is done by bees (and other pollinating insects). (It can also be done with a paintbrush in desperate times.) As pollination is usually done by bees, both trees need to be flowering at the same time.
And this is where flowering groups come in. Apple trees are put into groups to allow one to buy a tree that flowers at the same time. Trees in group 1 will always flower before trees in group 2 and trees can be pollinated by trees in neighbouring groups (+/-1). (Some retailers may provide specific dates of when a particular group flowers, but this is only reliable for a particular location. The same group will flower at different times in different parts of the country.)
Sadly, not all apple trees will pollinate each other. Triploid varieties, such as Bramley’s Seedling, can’t pollinate other varieties, but can be pollinated by others. Hence, if you are to buy a triploid, you need to purchase two other trees. Similarly, closely related varieties will not pollinate one another due to genetic similarity. Thus, it might be unwise to pair Queen Cox, a descendent of Cox, with Cox. If you are confused, try pairing a traditional American variety with a European one (Golden Delicious with a Cox).
Crabapple trees will pollinate apples and are considered the best pollinator’s around due to their long flowering times. (They produce flowers on spurs and then one-year old wood). Crabapples are commonly planted by commercial growers at the end of an orchard.
Family trees – trees where two more varieties have been grafted together – will pollinate each other. You can hypothetically graft loads of varieties to one tree and the pollination will be excellent.
Lastly, and perhaps most importantly, the colour of the first flower a bee harvests pollen from will be a bee’s preference from then on. Thus, if it lands on a pink flower, it will then seek out other pink flowers, forgoing radically different colours. This is important as if you wish to buy a crabapple make sure it has the same colour blossom as apple blossom (white with a touch of pink). (All apple blossom is the same colour.)
Bees also have a preference for violet and blue flowers, which have the highest concentration of nectar. A lavender bush is famous for its ability to attract bees. Such plants will pick up a large percentage of bees, who will then seek out similar colour blossom. To avoid this, growers may remove such plants.
Do I Need to Buy A Pollination Partner?
Unless you live in an isolated location, it is probable there is another apple or crabapple nearby. Honeybees roam several miles in search of blossom, so if you are in urban area you are likely fine. Solitary bees will roam a mere 200 yards and bumblebees up to a mile.
How Do I Know if My Tree is Well Fertilised?
Well-pollinated trees are associated with a large fruit diameter and lot of seeds (7-10). A poorly pollinated tree will have small and misshapen fruit.
Choosing the Best Pollinator
So, from what we’ve learnt for optimal pollination a tree needs a partner that (1) flowers at the same time, (2.) with similar colour blossom, and (3.) is not a triploid.
As previously mentioned, crabapples flower for a long time and make an excellent choice for a commercial orchard. Their fruits are small and easily distinguishable from apples, and as they bear on one-year wood they can be pruned each year after flowering and will produce an abundance of blossom. They can be trained into a narrow pillar shape to maximise space and should be not taller than your apple tree to ensure bees move from canopy to canopy. Crabapples are often planted as the 6th and 7th tree, equidistant to ensure best coverage.
Note: although white flowers with a touch of pink that are taken as synonymous with apple blossom by bees, red and pink crabapples will be selected by bees but in a lower frequency. Most apple trees reside in group 3.
Profusion, which flowers for a whopping 4 weeks, produces red flowers and resides in group 2.
Jorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!
His ideal afternoon would involve a long walk, before settling down for scones.
Jorge is a journeyman gardener with experience in growing crops.