Hellikki Rhododendron Hellikki Rhododendrons are a very hardy plant with purple-red flowers. New growth shows yellowish indumentum giving the plant an added interest. Primary Color: Purple Bloom Time: Late Height in 10 Years: 5' Hardiness (Temperature): -25 Sun / Shade: Morning Sun, Afternoon Shade Landscape Category: Shrub Genus: Rhododendron More plants in: Hybrid Rhododendrons Find out if this plant is available: Rhododendron and Azalea Availability List