Sources vary on the ratio of males to females needed for good pollination. In general, one male winterberry holly is adequate for pollinating three to six or more female plants. To ensure pollination, a male winterberry holly must be planted within 40 to 50 feet of a female winterberry holly.

How do you tell the difference between a male and female winterberry?

The flowers on female plants will have a raised green nub in the center, which turns into the berry; the flowers on male plants have recessed centers and a crown of fluffy yellow pollen-bearing anthers.

Why doesn't my winterberry have berries?

For the native deciduous winterberry, Ilex verticillata, one male can pollinate from five to ten female hollies. ... If a holly plant fails to produce berries, it is either a male (and will never produce berries) or it is an unfertilized female.