Q. Why do you need to have a “boy” holly bush and a “girl” holly bush in order to have berries?

In order to self-pollinate (make berries), a plant needs both male (stamen) and female (pistil) flower structures. Holly plants have either all male flowers or all female flowers. In order to produce berries, a landscaper needs to plant a male plant within 30-40’ of females in order to yield berries. The plant that produces the berries is the female holly.

Now, here is the situation. You've had one holly shrub in your yard, and it has never produced berries; you learn, subsequently, that holly shrubs are dioecious and need a mate, so you correctly reason that the lack of berry production must be attributed to one of two possible causes:

1. You have male holly shrub.
2. You have a female holly shrub, but it’s flowers have not yet been pollinated.

So now you have to determine what gender your holly shrub is. Question is, though, without having the crutch of the holly berries (a sure indicator of the female gender in holly shrubs) to rely on for identification, how can you tell a male holly from a female holly.

The answer lies in the flowers (of course, this limits identification to springtime, when both male holly and female holly come into bloom). Both male hollies and female hollies bear flowers that have 4 petals -- so that's no help in identifying them. However, take a closer look at the flowers, specifically, at what protrudes from their centers. Male holly flowers have 4 yellow stamens; each female holly flower has a green ovary (that's the green "bump").

Holly plants are a diverse lot. Holly plants “are one of the few genra that can be grown in all 50 states” in the U. S., writes the curator of the Scott Arboretum in Pennsylvania. Holly plants come in all sizes, ranging from spreading dwarf holly shrubs 6” in height to holly trees 70’ tall. Holly shrubs are attractive in foundation plantings or as borders for gardening plots. Holly trees and the taller shrubs can be used to screen out traffic or neighbors, or as striking accent plants on a lawn. Hollies prefer to grow in acidic soils, which is why they do so well in oak forests.

Did you know that in Christian folklore the prickly leaves of Christmas holly trees came to be associated with Jesus’ crown of thorns, while their berries represented the drops of blood shed for humanity’s salvation?