Prickles and thorns are an evolved defense against herbivores — animals that eat plants — and can also aid in growth, plant competition and water retention, according to the study.

Byington calls herself a collector of roses — she adores variety and aims to have some of every kind — and says she has about 200 plants. Her husband would argue that she has many more, she added.

As on a rose bush or a blackberry, the prickles arise from the outer skin on the stem, and they do not contain any vascular tissue (that is, water-conducting) as do thorns.