Chestnut Trees Flowering

Pollination of the sweet chestnuts tree

Chataignier, Fleur femelle

Female Flowers

The male flowers are different from female flowers, and present on the same tree.

The sweet chestnut tree is Monoecious. 

Chataignier, fleur mâle

Male Flowers



The flowers are arranged in long catkins of two kinds. Some catkins are made of only male flowers, which mature first.

Other catkins have these pollen-bearing flowers, but also carry near the twig, small clusters of female or fruit-producing flowers.

According to the presence or the absence of stamens on one hand, and the size of the filament on the other hand, the varieties of sweet chestnut tree can be:

  • Without stamen (astamineae): they grow regular-size catkins, but their flowers do not bloom or produce either anthers or pollens.

  • With disturbed stamen (brahistamineae): Unlike the previous breed, they grow a few short-stamen (1-3 mm) anthers, but they contain only a few, barely germinating pollens.

  • With medium-length stamen (mesostamineae): They grow several short-stamen (3-5 mm) anthers, which contain enough germinating pollens.

  • With long stamen (longistamineae): They grow a lot of well-developed, long-stamen (5-7 mm) anthers, which contain a great amount of germinating pollens.

Astamineae sweet chestnut trees are male sterile, brahistamineae and mesostamineae are practically also male sterile. Only the longistamineae varieties have a real pollinating capacity.


The pollination

The cross-pollination is really necessary for the sweet chestnut tree. The self-pollination gives very low result even to longistamineae sweet chestnut trees.

If you want an important harvest, it is really important to plant pollinators (longistamineae varieties) different from the principal variety in the orchard. You can use different pollinators that shall cover as good as possible the period of blooming female flowers. (The choice of pollinators are indicated for each variety in our catalog)

The climatic conditions during blooming that occurs very late in the second half of June and in early July are going to determine the way of pollination, and its efficiency.
A warm temperature and a low hygrometry will favor the liberation of the pollen grain which will be carried by the wind or by insects. (The information about the number and the arrangement of pollinators in the orchard is indicated in the section “Help to the plantation”)

 « Aide à la plantation »).

  • In the area where the hygrometry is low (Mediterranean area and Italy), the wind will spread the pollen efficiency: Anemophily or wind pollination.

  • n the more humid area (West and South-West of France for example), the pollen become sticky. So the fertilisation by the wind is extremely limited.  Under these conditions, Insects, especially bees will ensure the fertilization: Entomophily, pollination by insects.


: the honey produced by the bees is very popular.

It is a bitter and wooded honey, one of the most powerful and of the most persistent.

Its color is dark. It has a pronounced smell and stay liquid for a long time.

Abeille pollinisant un chataignier

(Photo :