At present the arboretum contains some 2,280 identified species, with major collections of Acer, Berberis, Deutzia, Euonymus, Malus, Lonicera, Philadelphus, Quercus, and Rhododendron.
Despite the occasionally extreme privations, and accompanied only by a boy guide, Comber sent back seeds and herbarium specimens of over 1200 species, including the Chilean Fire Bush, Nothofagus antarctica, and several species of Berberis and Eucryphia.
Other concentrations include the Chilean species of the widespread genus Berberis, the usage of computer models in evaluating methods of phylogenetic analysis, and serving on a committee of botanists (including D.J. Pinkava) working on a new manual of the vascular plants of Arizona to replace the aging Arizona Flora by Kearney and Peebles (last updated in 1960).
The larvae feed on various deciduous shrubs and trees, including poplar, oak, hazel, amelanchier, alder, antelope brush, Symphoricarpos, and Berberis.
It breeds in alpine shrub forests of Berberis, Rhamnus, Rhododendron, and Salix at 3,200–4,235 m altitude, descending in winter to slightly lower levels where it occurs in coniferous forests, primarily Picea.