Are blackberries self pollinating? Or do they need insects to pollinate them?

Question

Are blackberries self pollinating? Or do they need insects to pollinate them?

Answer 1

Actually, I beg to differ with the assertion that almost all blackberries are "self-pollinating". For example:

"Blackberry fruit is borne on the current year's growth with usually 10 to 20 flowers per cluster. Blackberries and raspberries are an aggregate fruit with individual pistils which form druplets. To obtain a large well formed berry most of the individual pistils in an inflorescence should be pollinated. Inadequate pollination results in smaller or imperfect fruit since not all seeds and druplets are formed. Blackberries range from completely self-fruitful to completely self-unfruitful. Most erect blackberries are fruitful yet trailing cultivars often require cross pollination. It is often reported that cross pollination results in highest yields. Several different blackberry cultivars should be planted together to insure cross pollination particularly if wild blackberries are not in the vicinity."

So, there is considerable variation in the degree of reliance on self- vs. outcrossed pollen in blackberries.

Source: http://edis.ifas.ufl.edu/HS104

Answer 2

Self-pollinating, except for Cascade Trailing.