Thuja occidentalis 'Trompenburg' / Trompenburg eastern arborvitae

Thuja occidentalis 'Trompenburg' is a slow growing, narrowly upright, dwarf selection of eastern arborvitae with dense, irregular, ascending branching holding sprays of yellow-green foliage than darkens somewhat in winter. After 10 years of growth, a mature specimen will measure 40 inches (1 m) tall and wide, an annual growth rate of 4 inches (10 cm).

This cultivar originated as a seedling selected in the mid-1980s by J.R.P. van Hoey Smith, who named it in honor of the famous arboretum in Rotterdam, The Netherlands.

Thuja occidentalis 'Trompenburg' — a 35-year-old specimen in a private garden in Bellingham, Washington (USDA Zone 8a / Modified Mediterranean Climate).
Photo by Roger Iverson
Thuja occidentalis 'Trompenburg' — a closeup of foliage detail.
Photo by Roger Iverson
Thuja occidentalis 'Trompenburg' in a private garden in Petaluma, California (USDA Zone 9b / Mediterranean Climate). Plant is showing its winter color. It has also been periodically sheared to maintain this irregular globose form.
Photo by Sara Malone