Blue Chaste Tree. Chaste tree carries several sacred names, which more or less directly refer to its reputation as an anaphrodisiac. The chaste tree is a sprawling plant that grows 10-20 ft and about as wide. Branched flower clusters are produced on new wood in late spring and early summer in a great flush that makes the tree look like a hazy purple cloud. Flowers are followed by a fleshy fruit that contains four seeds that are sometimes used as seasoning, similar to black pepper. Easy to grow in almost any soil that has good drainage! Even tolerant of salt drift.