Acer shirasawanum var. shirasawanum
Native to (or naturalized in) Oregon:
- Broadleaf deciduous small tree or shrub, 10-30 ft (3-9 m) tall and similar width [in its habitat 50 ft (15 m)]. Leaves simple, opposite, about 6 x 6 cm, some larger, round (suborbicular), 9-13 lobed, each lobe has an acuminate tip, margin doubly serrate; petiole to 7 cm, glabrous (without hairs); fall color yellow. Flowers in small, erect clusters, petals white to pale yellow. Fruit in erect clusters above the leaves, glabrous, wings held near horizontal, to 2 cm.
- Sun or shade.
- Hardy to USDA Zone 6 Native to Japan, the Hanshu and Shikoku Islands.
- A number of selections have been made, but many are difficult to locate and are likely to be found only in "specially nurseries" Below is a short list, the most common selection is ‘Aureum’:
- ‘Aureum’ - shrubby tree, leaves greenish-yellow, may be golden-yellow to orange in the fall, sometimes not much color.
- ‘Autumn Moon’ - leaves greenish-yellow, spring foliage pinkish the color may be retained into summer, in full sun fall colors may be orange and red. Some say it is noticably different than A. s. ‘Aureum’ others opine that it is similar.
- Moonrise™ - ( syn. 'Munn 001') multi-trunked, low-branching tree, mature height probably about 18 ft (5.5 m) with a similar spread. New growth emerges carmine red, the leaves cup down, then open and spread out as they turn to yellow in sun, shade leaves are lime-green. In westerm Oregon it withstands full sun with very little leaf scorch. A chance seedling of A. s. ‘Aureum’ discovered by Carl Munn, in Brooks, Oregon, grows more vigorously than ‘Aureum’ (Plant Patent 16,718, June 26, 2006).
- ‘Palmatifolium’ - a small tree or multi-stemmed shrub to about 30 ft (10 m) tall and a similar width. Leaves about 10 cm wide, bright green, deeply and sharply cut lobes, turn red, orange, and/or yellow in fall. Reportedly will take full sun (J.D. Vetrees). Its origin is unclear.
- ‘Red Dawn’ - very upright to 12 ft (3.5 m), leaves deeply lobed, red in spring and red-maroon color in summer, crimson fall color. Some suggest that it may be a hybrid because leaf shape is somewhat similar to Acer palmatum and some characteristics are not stable.
- In Maples for Gardens (1999), the authors, C.J. and D.M van Gelderen, list the following additional selections:
- ‘Diane’ - 16-20 ft (5-6m) tall, leaves fresh green, fall color yellow.
- ‘Ezo no o momiji’ - 20-26 ft (6-8 m), leaves dark green, fall color yellow.
- ‘Gloria’ - to 26 ft (8 m), leaves deeply incised, dark brown-red turning lighter in fall. Might be a hybrid with A. palmatum ‘Bloodgood’ being the male parent.
- ‘Microphyllum’ - 26-33 ft (8-10 m), leaves smaller than those of the speces (6-10 cm wide), yellowish green, fall color yellow. Syn. A. japonicum ‘Microphyllum’ and may also be identical to Acer shirasawanum ‘Juni hito e’.
- ‘Susanne’ - shrub to 16-20 ft (5-6 m), leaves lemon yellow when unfolding, then soft green in summer.
- ‘Yasemin’ - shrub to 33 ft (10 m) tall and 10-13 ft (3-4 m) wide, leaves a shiny dark purple, deeply dissected, might be a hybrid with A. palmatum ‘Bloodgood’ being the male parent.