October 11, 2020

Pollen Basics

Several climatic factors effect pollination

  1. Temperature below 55-60° F reduces bee activity
  2. Temperature above 85-90° F dries stigmatic surface and pollen grain doesn’t germinate
  3. Windy weather slows bee activity
  4. Rain during anthesis (time stigmatic surface is receptive)
  5. Presence of other flowers — the fruit plants generally are poor nectar producers and bees will naturally seek out the best nectar producing flowers
  6. Most insecticides will reduce bee activity — therefore do not spray them during bloom

Pollination requirements for several crops

Those fruits listed as self-fertile will set fruit with their own pollen.

Apple: Cross pollination always needed to produce adequate fruit crop.

Apricot: All varieties are self-fruitful but cross pollination is helpful.

Cherry: (1) Sweet–most varieties are self-unfruitful. However there are newer varieties that are self fruitful such as Lappins, Stella, Whitegold, Sweetheart and Blackgold. (2) Red tart – the commercial varieties are self-fruitful.

Nectarine: Most varieties are self-fruitful; however, those having J. H. Hale in the parentage will require cross pollination.

Pear: A few varieties are self-fruitful. But a pollinizer will improve crop.

Plum: A wide diversity occurs in the plums. About half of the varieties are self-fruitful and half are not. To be on the safe side pollinizers should be provided.

Almond: Must be cross pollinated by another variety.

Black Walnut: Self-fertile but often the pollen is not shed when stigma is receptive. Use at least two varieties or seedlings to assure good crops.

Carpathian Walnut: Self-unfruitful – at least one other seedling tree required to assure a crop.

English Walnut: See Carpathian Walnut.

Persian Walnut: See Carpathian Walnut.

Pistachio: Must be cross pollinated.