Just like apples, pears are predominantly self-sterile and need to be paired with a pollination partner to produce fruit. There are a few partially self-fertile varieties that will crop without a partner, but any crop is much improved with one. Conference and Obelisk are the only varieties that are truly self-fertile and will produce a decent crop unaided, but for bumper crops we recommend you partner up.
Pear trees produce flowers that have both male and female reproductive organs, the anther and stigma respectively. The anther produces pollen and the stigma contains ovules. Pollen needs to be transferred from the anther to the stigma. This is usually done by insects, which flowers are designed to attract. Once a pollen grain reaches the stigma, it will start to form a pollen tube.
From here two things can happen. If the pollen grain is incompatible, an enzyme will be produced, which stops the pollen tube from growing, preventing fertilisation. If it is compatible, the pollen tube will grow down the stigma and deposit sperm onto the ovules. Fertilised ovules grow into fruit.
Pollen may be incompatible if it is from the same tree, from a closely related variety or a triploid variety. Self-fertile trees are different in that they produce pollen that will fertilise its own ovules.
Pear trees are put into pollination groups with group 1 flowering very early and group 6 flowering very late. Group 1 will always flower before group 2. Some websites will provide a specific flowering date, but it really depends on your location. Pears will be pollinated by any variety in the same or neighbouring (+-1) flowering group. This is because by the time the flowers of group 3 open, group 1 have already closed, making pollination impossible.
Do I Need to Buy a Pollination Partner?
Unless you live in an isolated location, it is probable there is another pear tree nearby. honey bees, the principal pollinator of trees, will forage several miles in search of nectar, so if you are in an urban area it is likely you are fine.
How Do I Know if My Tree is Well Fertilised?
Well-pollinated fruits have a large diameter and lot of seeds. Poorly pollinated fruits are small and misshapen.
Can Different Pear Species Pollinate Each Other?
Asian pears (Pyrus pyrifolia) will pollinate European pears (Pyrus communis) and vice-versa. Ostensibly, ornamental pears will also fertilise fruiting pear trees.
Other Than Buying A Pollination Partner How Else Can I Improve Pollination?
It is a little known fact that the first flower colour a bee lands on will be a bees preference thereafter. Bees also have an innate preference for violet/blue flowers which have the highest concentration of nectar. It is therefore unwise to plant flowers such as lavender near your orchard. Pears produce pale white flowers, which bees may forgo for more vivid flowers. The presence of weeds such as dandelion (Taraxacum officinale) and chickweed (Stellaria media) can also distract bees, so it is worth deheading them.
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.