Some of the most common citrus trees to sport thorns are Meyer lemon, most grapefruits and key limes. Thorns on citrus trees develop at the nodes, often sprouting on new grafts and fruiting wood. Some citrus trees with thorns outgrow them as the tree matures. read more
Orange tree stems are frequently armed with thorns, which are most numerous and prominent before trees begin bearing fruit. Thorns, along with spines and prickles, are assumed by many researchers to be a plant-evolved anti-herbivore defense mechanism. read more
Trifoliate orange trees reach 15 to 20 feet tall and wide with a tangled web of thorny branches. Green 2-inch-long thorns render trees into formidable barriers, especially when multiple plants are grown as a hedgerow. White, citrus-scented flowers appear in spring, followed by golf ball-sized fruits. read more