Apple blossom brightens up the spring garden. This glorious show runs from late April to early June, depending on variety. We should follow the example of countries like Switzerland that organise special ‘apple blossom walks’ or Japan with their famous love of cherry blossom.

The apple variety, Arbroath Oslin is among the earliest. One of our oldest apples, it’s named after Arbroath Abbey where it was grown centuries ago.

Arbroath Oslin admittedly doesn’t date back 700 years to when the barons assembled at the abbey to draw up the famous Declaration of Arbroath. This must have been a taxing occasion as they negotiated a document declaring the right of the Scottish people to determine their own future.

So I like to think they could also relax in the monastery’s fine gardens. The monks were early pioneers of ‘grow your own’, producing all their own fruit and veg. The abbey later became the home of Arbroath Oslin.

This early variety would have been in full bloom a fortnight after the barons appended their seals on the 6th of April. Oslin’s clusters of deep pink flowers would certainly have diverted their minds from matters of state.

The trees would have yielded tasty yellow desert apples by the end of August. For successful pollination, the pollen grains produced by male stamens on blossom attach to a visiting insect, often a hardy bumblebee. They get a lift to blossom on a different apple variety and germinate on contact with the female stigma. The bee is rewarded with sweet nectar.

Pollen needs warm temperatures, ideally 20 - 25C, but is fortunately still viable in spring when 10 - 15c is more probable. Unfortunately, frost can damage the female stigma even if the flower looks healthy, and this makes fertilisation impossible.

Sometimes the damage is very noticeable. Last year a series of hard frosts left brown and wizened blooms and resulted in virtually no harvest. There was ne’er an apple to be seen on several stalwarts, like Tower of Glamis. My apple press gathered cobwebs.

Heavy rain can also be nearly as damaging since sodden pollen grains won’t adhere to the few insects on the wing in that weather. So Heaven knows what’s in store later this spring.

Most apple trees are self-infertile so need to cross pollinate with other varieties that are in flower during the same fortnight. So to help choose compatible varieties, they’re divided into flowering groups. The RHS identifies 7 groups, although some nurseries use six classifications, and a few reduce it to four.

Where there are six or seven classifications, select 2 or more varieties from the same or neighbouring groups. Most of the more commonly grown varieties are in the 3-4/ A-C bracket, and nurseries will help with your choice. When a nursery only uses four categories, it’s safer to select 2 or more trees from within the same broad group.

There are 2 exceptions to these pollination groups. A few varieties, such as James Grieve, are self-fertile, so work when you’ve only space for one tree. But as a general rule with plants, self-fertilisation produces poorer germination and lower yields, so I’d recommend providing a partner for even a self-fertile variety.

Secondly, some varieties called triploids, need different treatment. Unlike most apples, triploids have 3, not 2 chromosomes and are not only self-infertile, but don’t fertilise other trees. They therefore need 2 other varieties for pollination. But don’t be put off: triploids include, Bramley’s Seedling, Ribston Pippin and Blenheim Orange.

As you may have worked out, Arbroath Oslin is group 2.

Plant of the week

Primrose, Primula vulgaris, is the plant for Easter. Pale, yellow delicate flowers and a light scent of honey when the sun shines. Enjoy the sight of them carpeting a bank or growing under a hedge and pick just a few to bring indoors or decorate a cake.

 

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