Prunus Subhirtella: Your Guide to Pink “Rose October Cherry”

Prunus subhirtella, particularly the ‘Autumnalis Rosea’ cultivar, is a highly prized ornamental cherry tree renowned for its unique blooming characteristics and delicate beauty. This triploid hybrid, derived from the small Higan cherry and other Prunus species, has been widely cultivated since the late Edo period in Japan, earning a special place in horticultural circles.

The species is notable for its biannual flowering habit, producing blossoms in late March to early April and again from October to December. This exceptional trait has led to its common names “October Cherry” for the white-flowered variety and “Rose October Cherry” for the pink-flowered form, making it a valuable addition to gardens seeking year-round interest.

I. Basic Introduction

Prunus subhirtella ‘Autumnalis Rosea’ is a complex hybrid, resulting from the crossing of the small Higan cherry (itself a hybrid of Prunus incisa and Prunus pendula) with other cherry species. Its genetic makeup contributes to its distinctive characteristics, particularly its extended and repeated flowering periods.

This cultivar belongs to a select group of double-flowering Higan cherry varieties that exhibit the unusual trait of blooming intermittently from autumn through spring. The autumn flowers tend to be smaller, while the spring blossoms are larger and borne on longer pedicels, creating a more dramatic display.

II. Morphology and Characteristics

Growth Habit

• Deciduous small tree
• Height: 6-10 meters (20-33 feet)
• Form: Vase-like shape with spreading branches
• Bark: Smooth, gray-brown

Foliage

• Leaves: Deciduous, 3.5-5.5 cm long, 2-2.5 cm wide
• Shape: Elongated oval to obovate
• Apex: Gradually tapering
• Base: Obtuse
• Margins: Sharply double-serrated or single-serrated
• Texture: Pubescent, with denser hair along veins on the underside
• Petiole: 1 cm long, densely pubescent
• Nectaries: Two short-stalked glands at leaf base
• Stipules: Linear

Flowers

• Inflorescence: Umbel-like clusters
• Pedicel: Pubescent with upward-facing hairs
• Calyx: Urn-shaped with slight constriction at top
• Calyx lobes: Serrated or ciliate on lower half, pubescent on exterior
• Petals: 10-16, linear-oblong, pale pink to white
• Inner petals: Often with remnant single anther (petaloid stamens)
• Stamens: 40-60
• Pistil: Longer than stamens
• Style: Glabrous on upper portion, pubescent on lower part and ovary apex

Flowering Characteristics

• Bloom periods: Biannual – late March to early April and October to December
• Flower size: Medium
• Type: Double-flowering
• Color: Pale pink (‘Autumnalis Rosea’) or white (‘Autumnalis’)

Cultural Significance

Prunus subhirtella ‘Autumnalis Rosea’ has been widely cultivated since the late Edo period (early 19th century) in Japan. Its ability to flower during the autumn and winter months, when most other plants are dormant, has made it a highly valued ornamental tree in Japanese gardens and beyond.

The ‘Autumnalis Rosea’ cultivar shares its autumn-blooming trait with another double-flowering cherry, the Fukuhana Early Cherry (Prunus × subhirtella ‘Fukubana’), though they are distinct varieties with their own unique characteristics.

In conclusion, the Prunus subhirtella ‘Autumnalis Rosea’, or Pink “Rose October Cherry,” is a remarkable ornamental tree that offers beauty and interest far beyond the typical spring cherry blossom season. Its unique flowering habit, delicate pink blossoms, and rich cultural history make it a prized addition to gardens seeking year-round appeal and a touch of Japanese horticultural heritage.