Q.How To Identify The Sex Of A Holly Bush
Hello, I have one holly bush that doesn’t produce berries and hasn’t for a few years. I’m not sure if it is because it is a male and needs a female or a female that needs a male. Is there a way to tell the difference on a bush that doesn’t have any flowering or berries at the moment? Thanks very much.

The flower is the distinguishing plant part between male and female. Male flowers have a stamen which produces pollen. Female flowers have a pistil. The complicating piece is different cultivars of holly may bloom at slightly different times. If you don't know the specifics on your holly, getting a useful mate for it may be trial and error.

In general, you need to study the type of flowers to decide if the plant is male or female. See: https://www.gardeningknowhow.com/ornamental/shrubs/holly/how-to-tell-the-difference-between-a-male-and-female-holly-bush.htm