[crosseyedsheep]

A summary of what I learned about fruit pollination

About a year or so ago I started to look into the whole process of growing fruit trees. Even though I wasn’t too knowledgeable about the ins and outs of fruit production I wasn’t entirely unaware of the necessity of pollination to produce fruit. So, I started to read books and websites to become more familiar with the process of fruit tree pollination. The following is an attempt to summarize what I learned to give others a heads up and save on all the research which I had to do to gather all the information. The following relates to Apples, Pears and plums but probably applies to other fruit types as well.

To start with, I’ll explain pollination in simple terms. A flower usually has a male part called the anther which produces pollen, and a female part called a stigma, for fruit to start forming pollen must be transferred from anther to stigma. All sounds so simple doesn’t it? Unfortunately there are some factors which complicate things so read on.

Fruit trees can be divided into three categories when it comes to pollination, as follows:

Self-sterile; These plants produce pollen themselves but require pollen from a different variety to produce fruit. Usually if you plant two compatible self fertile varieties near each other they will be able to pollinate each other, hence each one is a pollinator, sometimes one variety on it’s own will produce fruit but this is where pollen is carried from another compatible variety in the local area. Pollen can be carried for quite a distance by bees gathering nectar for example. Most apples and pears are self-sterile.

Self-sterile Triploid; These plants produce little or no pollen, so they don’t tend to pollinate other varieties. If planting a Self-sterile Triploid, you need to plant two other pollinator varieties nearby, to produce fruit on all three plants. It’s not that the Self-sterile Triploid needs pollen from two other plants as the name and planting tips may seem to suggest, it’s just that the second pollinating variety (If you only planted one) needs to get pollen from somewhere as well, and the Self-sterile Triploid isn’t going to provide it, so the additional third variety is necessary, hence the second and third varieties pollinate each other and the Self-sterile Triploid gets pollen from one or both of the others. The Brambly seedling culinary apple is probably the best known example of a Self-sterile Triploid.

Self fertile; Plants which are classed as self fertile have the ability to reproduce when it’s own flowers stigma receives pollen from it’s own flowers anther. Most plums are self fertile and some apples but very few pears, pears which are, are usually only partially self fertile. A self fertile fruit tree can produce fruit even when grown on it’s own. However, in most cases self fertile fruit trees will produce a much better crop when cross pollinated with a different variety.

How to choose compatible pollinators:
For two plants to successfully pollinate each other, not only does their pollen have to be compatible but they have to be producing the pollen at the same time, i.e. they have to be in bloom at the same time. Compatable varieties which bloom at the same time are said to be in the same pollination group, Pollination Group A is the earliest flowering group, B the next etc. Adjacent group flowering times tend to overlap so a plant from C may be pollinated by a plant fron B or D (As long as their is an overlap with those particular plants). To select compatible varieties, the following site is excellent, and certainly the best I’ve come across on the web:

http://www.keepers-nursery.co.uk/default.aspx

Edit: See Italics


Crosseyedsheep

[GPI]

Great informative post, Crosseyedsheep.
Worthy of a sticky which we can add lists of pollination partners etc. to as Irish gardeners grows.

[crosseyedsheep]