Picea abies 'Diffusa' os a slow-growing, beehive- or dome-shaped selection of Norway spruce that grows with multiple terminal leaders that are densely branched, holding congested, yellow-green foliage. After 10 years of growth, a mature specimen will measure 16 to 24 inches (40 - 60 cm) tall and 12 to 20 inches (30 - 50 cm) wide, an annual growth rate of 1.5 to 2 inches (4 - 5 cm).
'Diffusa' is an old English cultivar of unknown origin, known to the nursery trade since the early 1900s. Murray Hornibrook first described it in 1923 in his book, Dwarf and Slow-growing Conifers, where he describes it as "low-growing with distinctive yellow-green foliage." In fact, in the Latin language, "diffusa" means, "spreading" which doesn't properly describe the plants we see today. Examples of this plants now seen in the cultivation are generally taller and greener, suggesting that at some point, a different plant got substituted for that name or a reversion of some sort was propagated and forwarded.
