Styrax japonicus is a small tree that reaches 6 to 9 m with moderate growth rate and hardy across US Department of Agriculture Hardiness Zones 5 to 8 (Dirr 1998). It is popular for residential and commercial landscapes due to its small stature and prolific production of lightly fragrant flowers. There have been many introductions including those for upright growth and floriferousness (e.g., Snowcone™ ‘JFS-D’), heat tolerance (e.g., ‘Emerald Pagoda’; Dirr 1998), purple foliage (‘Evening Light’), and weeping habit (e.g., ‘Fragrant Fountains’ and ‘JLWeeping’). More recently, Nightfall™ (S. japonicus ‘JFS 6SJ’ PP 34817) was introduced by J. Frank Schmidt and Son Nursery. Nightfall™ combines purple foliage with weeping habit and has white flowers. Its patent indicates it was an open-pollinated seedling collected from ‘Evening Light’, and the pollen parent is unknown; however, on the basis of its white flowers, it was likely ‘Fragrant Fountains’. ‘ORSTSTYx1’ was selected for its excellent vigor, weeping habit, purple foliage, and pink flowers. To our knowledge, it is the only purple foliage, weeping cultivar of Japanese snowbells with pink flowers.
Origin
Controlled crosses of S. japonicus ‘Evening Light’ USPP24168 × S. japonicus ‘JLWeeping’ USPP23755 Marley’s Pink® were made in 2016 and seedlings germinated in 2017. The original seedling was accessioned in the Ornamental Plant Breeding Program at Oregon State University as H2017-001-002, indicating it was the first cross combination accessioned in 2017 (H2017-001) and the second seedling resulting from the cross. It was planted 17 May 2018, at the Lewis Brown Research Farm where it was evaluated as 91.02, indicating it was planted in row 91 and plant 2 (Fig. 1A). Propagation material as budwood and grafting material was distributed under material transfer agreements between 2020 and 2022, during which time commercial nurseries evaluated its propagation and production characteristics as well as how well it maintained its ornamental traits. In 2023, S. japonicus ‘ORSTSTYx1’ was released by the Oregon Agricultural Experiment Station, and a US plant patent application was submitted.
The original plant of Styrax japonicus ‘ORSTSTYx1’ growing in its original field location (91.02) at the Lewis Brown Farm in Corvallis, OR, USA on 3 Jun 2023. (A) Illustrating form and weeping habit and (B) its dark foliage and flowers that are distinctly pink in bud and open to a blush pink. Initial foliage emerges green during early spring and subsequently develops characteristic dark foliage.
Citation: HortScience 59, 6; 10.21273/HORTSCI17782-24
Description
‘ORSTSTYx1’ exhibits a strict weeping habit but is vigorous and the original plant was 2.3 m tall with a trunk diameter of 6.4 cm after 7 years from seed and 5 years from field planting (Fig. 1A). Its vegetative and floral traits are similar to but discernable from its female and male parents (Table 1). It has alternately arranged leaves that are smooth and glossy abaxially and adaxially. Leaves are 2.9 cm long and 7.7 cm wide and elliptic with acuminate apex, cuneate base, and serrate margins. Leaves are variable in color, with interior leaves generally greener than exterior leaves receiving full sun. Emerging young purple leaves are RHS N200A (Royal Horticulture Society 2007) adaxially and RHS N200B abaxially (Fig. 1B). Emerging green leaves RHS 144A adaxially and RHS 146B abaxially (Fig. 1B). Mature expanded purple leaves are RHS N200A adaxially and abaxially (Fig. 2A and B). Mature expanded green leaves are RHS N137B adaxially and RHS 146A on abaxially.
Comparison of Styrax japonicus ‘ORSTSTYx1’ to its female parent, ‘Evening Light’, and male parent, ‘JLWeeping’. Colors presented are Royal Horticulture Society Color Chart (2007).i
Foliage of Styrax japonicus ‘ORSTSTYx1’ original plant growing in its original field location in Corvallis, OR, USA taken on (A) 29 Jun 2022 and (B) 7 Jul 2021.
Citation: HortScience 59, 6; 10.21273/HORTSCI17782-24
Flowers are campanulate with ovoid petals that are RHS NN155C with a RHS 62D blush produced in pendulous racemes in which flowers are alternately arranged. There are generally five flowers per inflorescence with a lightly green-floral fragrance. Individual flowers persist 1 to 2 weeks. During 2023, flowering started 31 May and was done by mid-June, but in a typical year, flowering would occur ∼2 weeks earlier because Spring 2023 was notably cooler than usual.
‘ORSTSTYx1’ propagates well from chip budding, grafting, and in micropropagation and has been shown to grow well in production from any of these methods of propagation. Cutting propagation is relatively easy, but rooted cuttings do not overwinter well and losses will continue during production; thus, an alternate method is recommended. Plants have maintained their characteristics described here, particularly weeping habit, purple foliage, and pink flowers, following serial propagation. A voucher was collected from a field-grown plant on 8 Jun 2023, and deposited in the Oregon State University Herbarium and accessioned as OSC-V-269794.
Availability
S. japonicus ‘ORSTSTYx1’ was released in 2023 by the Oregon Agricultural Experiment Station and licensed exclusively to UpShoot, which has licensed exclusive marketing rights to Proven Winners® ColorChoice® Flowering Tree Program and will market it under a trade name of their choosing. For more information on growers and availability, contact Maria Zampini, Tree Program Manager, Proven Winners® ColorChoice® Flowering Trees via maria@upshoothort.com.
References Cited
Dirr MA. 1998. Manual of woody landscape plants: Their identification, ornamental characteristics, culture, propagation and uses (5th ed). Stipes Publishing, Champaign, IL, USA.
Royal Horticulture Society. 2007. The Royal Horticulture Society Colour Chart (5th ed). London, United Kingdom.