Picea omorika × pungens 'Troemner' is a synthetic hybrid of species Serbian spruce and P. pungens 'Koster.' It is a relatively narrow, extremely fast growing tree form with down-swept branching; long, extremely prickly needles, and attractive, purple seed cones. After 10 years of growth, a mature specimen will measure 20 feet (6 m) or more tall and 8 feet (2 m) wide, an annual growth rate in excess of 2 feet (60 cm).
This cultivar originated as a seedling selected in 1972 by Allan Troemner, a technician in the University of Wisconsin-Madison Forestry Department. He presented the selected plant to Dennis Hermsen and Edward Hasselkus to grow on, evaluate and eventually introduce to the nursery trade. This plant is often seen offered for sale under the commercial trade name, 'Blue Sky.'
