Not thornless, the thorns follow up right under the blooms. It has a slight scent in 100F weather, and red new growth. No blackspot or mildew; even while our overnight temperatures have been in the upper 60's to mid 70's. The blooms are very small with very few petals during this heatwave. It needs full sun. In spring 2012, we had one bloom, about 2 inches across with numerous petals, in med peach.