Chamaecyparis lawsoniana 'Alumii' / Alum's Lawson cypress

Chamaecyparis lawsoniana 'Alumii' is a vigorous, upright, tree form of Lawson cypress with dense, fastigiate branching, and plates of fernlike, blue-gray foliage. After 10 years of growth, a mature specimen will measure 12 to 18 feet (4 - 6 m) tall and 4 to 5 feet (1.2 - 1.8 m) wide, an annual growth rate of 12 to 18 inches (15 - 20 cm).

This cultivar has long been very popular in cultivation. In 1972 Gerd Krüssmann, in Handbuch der Nadelhölzkunde attributed its origin to R. Smith & Co. Nursery, United Kingdom. The cultivar name implies that this conifer was named for someone named Alum, but this can't be verified at this time.
Chamaecyparis lawsoniana 'Alumii' — a mature specimen in a nursery display garden in Serbia.
Photo by Tamaris Nursery, Serbia
Chamaecyparis obtusa 'Alumii' — a closeup of foliage detail.
Photo by AfroBrazilian - Own work, via Wikipedia, CC BY-SA 4.0, public domain photo