A couple of reasons we like Cestrums are their large colorful flower clusters and their ability to bloom continuously in the heat. Purple Cestrum has surprised us with its ability to withstand our zone 6b winters. The unique violet/lavender blossoms of this hardier-than-realized plant are certainly treasured in our garden from summer through fall. It is a hybrid of a species from Mexico (Cestrum elegans) and a species from Chile (Cestrum parqui). Its common name, Cretan Purple, leads me to believe the cross was made on the Greek isle of Crete. We are told of them growing to tree form there on the island while here they only get about 3' tall in a season.