Pinus × densithunbergii 'Jane Kluis' is a deliberate cross (grex) of Pinus densiflora and Pinus thunbergii. It is a dwarf, globose selection of hybrid pine with straight, rigid, fresh-green needles and prominent white buds. Typical rate of growth in most areas is 2.5 to 6 inches (6 - 15 cm) a year resulting in a shrubby tree 2 to 5 feet (0.7 - 1.5 m) tall and wide after 10 years in the landscape.
A very low growing compact plant, raised by Kluis Nurseries, U.S.A., before 1984. The buds are remarkably white; this may indicate that the plant is a hybrid with P. thunbergii. A very nice novelty. Received an Award of Merit from the Royal Boskoop Horticultural Society.
Rudolph H.W. Kluis, of Rudolph Kluis Nurseries, Marlboro, New Jersey is credited with origination, nomination and introduction of this fine cultivar.
My memory has it that Rudi performed a deliberate cross back in the early 70's with Pinus densiflora and Pinus thunbergii which yielded seedlings that exhibited a range of characteristics reflective of both parents. From this collection of seedlings (which Rudi called a grex), he selected five or six that had distinct features none of which he named except that of 'Jane Kluis'. 'Jane Kluis' was distinct from the others in that it was broader than tall, had coarser thunbergii foliage and had those distinctive white candles. All the others had the typical densiflora habit with some variation, and yet interestingly, all had that distinctive acid green color typical of 'Jane Kluis.'