Picea glauca conica 'Rainbow's End' - to 8' tall, with a second flush of growth in midseason being chartreuse to cream-yellow in foliage color Picea glauca densata - Black Hills Spruce - a slower growing, more dense and formal variety of the species treeform, to 20' tall by 10' wide NOTES. Translation. Big Berta White Spruce. Picea glauca ‘Big Berta’ is not your typical Dwarf Alberta Spruce, this cultivar is a “big ‘berta”. It has the same ‘Conica’ type juvenile foliage but the needles are much longer and growth rate is much faster, resulting in a more open form.