New frontiers for Japanese snowbells

While its strong wood may be used as ribs for umbrellas and walking sticks, it is better known for its tiers of bell-shaped blossoms adorning the branches in spring. The flowers, which can be fragrant, attract bees, butterflies and hummingbirds, and its gray-laced-orange bark offers winter interest.

Styrax japonicus, or Japanese snowbell, has been making waves in the industry, gaining attention from growers, breeders and gardeners as an uncommon compact ornamental tree.

Nightfall® (S.j. ‘JFS 6SJ’ PP34817), bred by J. Frank Schmidt & Son Co., made news grabbing both the judges’ and peoples’ choice awards in the Farwest Show New Varieties Showcase in 2022. In 2024, Robinson Nursery Inc.’s reblooming Starway to Heaven® (S.j. ‘RNI-RIXRED’ PP35353) repeated the sweep.

Wide appeal

Maria Zampini, owner of UpShoot Hort, leads the tree program at Proven Winners® ColorChoice® and is bullish on the appeal of Japanese snowbells. “I think in general that consumers are looking for nice, tidy, smaller-size selections to be a focal point in the landscape and/or for small spaces,” she said. “Snowbells tick many of these boxes as well as others like fragrance, being maintenance-free, disease- and insect-free, and more. I mean, what’s not to like?”

“There are lots of great reasons to grow Styrax,” agreed Ryan Contreras, an Oregon State University professor leading breeding programs in the Department of Horticulture program in Corvallis. “They like a bit of irrigation in summer, but there’s not a huge issue with any pests or pathogens.”

The trees thrive in both sun and partial shade, and are being offered in multiple profiles and bloom colors. Opinions differ as to the strength of fragrance, and the fall color isn’t especially strong.

However, their good manners and relatively compact size are a major plus amid increasingly dense housing, said John Lewis , president and owner of JLPN Inc., a propagation nursery in Salem, Oregon. JLPN introduced Marley’s Pink® snowbell (S.j. ‘JLWeeping’ PP23755, initially known as ‘Marley’s Pink Parasol’, which had to be renamed due to trademark issues).

Named after Lewis’ daughter Marley, this selection of S.j. ‘Pink Chimes’ appealed to Martha Stewart so much she planted an allée of them bordering her tennis court in 2016 (she later added first purple-leaf cultivar, S.j. ‘Evening Light’). “Snowbells are definitely taking off for us in popularity largely due to the great aspects of the tree and the ever-shrinking lot sizes of residential homes,” Lewis said. “You might have a small space to landscape, but plant lovers want to fit in as many ornamentals in as possible. The smaller stature of some cultivars can make that a reality. Plus, I think the consumers are becoming more sophisticated with their tree selections for the landscape. There are many species of trees that are so over-planted in the landscape, and Styrax really stands alone when it’s in bloom.”

Consequently, he is “seeing an increase in our seedling sales for growers that are wanting to increase production on some of the newer varieties that are on the market. We are currently growing the seedlings for grafting understock, and developing our grafting program, which will include our selection Marley’s Pink.”

Charting the change

Japanese snowbells, native to Korea, Japan and southern China, have a long history in the United States, and were introduced in the 1860s.

Schmidt has been breeding snowbells since introducing Snowcone® (S.j. ‘JFS-D’) in the early 1990s, said new plant development manager Guy Meacham. More pyramidal and uniform in branching than the species, “Snowcone® set us on the path to find better Styrax,” Meacham said, noting that it remains a top seller.

“The issue was that Styrax forms are extremely variable,” Meacham said. “If you plant 200 seedlings, you’ll have 200 very different plants. Some will be good; some will be bad. So, we wanted to create some standardized cultivars so growers would know they’d have a decent-looking plant.”

Japanese snowbells may be upright or weeping, and offer green or purple foliage, with flowers ranging from white or pink. The typical height ranges between 15–30 feet, although S.j. ‘Snow Drops’, introduced by Buchholz Nursery, is said to grow 3 feet tall by 2 feet wide in 10 years. It’s a dwarf upright form with white flowers.

Recent Schmidt introduction Nightfall wowed by combining purple foliage with contrasting white flowers and a dramatic weeping habit. The nursery recommends staking Nightfall to 6–7 feet to maintain its stature.

For Meacham’s money, some of the historical highlights in Styrax breeding and introductions, in addition to Schmidt’s, include:

• S.j. ‘Evening Light’, for that breakthrough purple leaf;
• S.j. ‘Spring Showers’, a seedling selection released by the National Arboretum in 2011; Marley’s Pink snowbell, for its abundant pink flowers; S.j. ‘Fragrant Fountain’ PP19664, a vigorous weeping white-flowered cultivar with a strong central leader; and Starway to Heaven® snowbell.

Zampini recommends three Oregon-bred favorites from Proven Winners® ColorChoice® Flowering Tree program:

• Swan Song snowbell (S.j. ‘ORSTSTYx1’ PPAF), bred by Contreras at OSU, is a dark-leafed weeping cultivar with pink flowers she calls “the next evolution.”
• Upright Starway to Heaven® snowbell, from Robinson Nursery in McMinnville, Oregon, is “perfect for smaller spaces” and bears white flowers against nicely glossy foliage.
• Marley’s Pink snowbell.

Starway to Heaven®, the recent Farwest double winner, stands out in both flower and leaf.

Maxing out at 5–8 feet wide by 20 feet tall, it easily fits in narrow corners. Another chance seedling discovery at Robinson’s Nursery, its foliage emerges red, turning deep green, and it blooms in spring with a repeat in fall.

Marley’s Pink brings the flower power, which is both abundant, and long-lasting.

“This cultivar blooms so heavily that the leaves will almost be dwarfed in size until the blooming is over,” said Lewis. “Everything this plant has for energy goes into the amazing fragrant pink show that it puts on every year. The pink color is very strong and doesn’t fade to a pale pink/white when exposed to heat.”

Cultivation challenges

Snowbells take well to rooting and hybridizing, but they can be finicky at some stages.

“There’s no trick about crossing them,” said Contreras. “The bigger trick is propagation and production. Some folks have been dropping Styrax in recent years as they can be a little more challenging. You can root easily from cuttings, but the cuttings don’t overwinter.”

A good portion of rooted cuttings fail, and we don’t know why.

“It’s been a mystery for 40 years,” said Meacham. “They just don’t leaf out, but the roots look absolutely perfect.”

In terms of attrition, Contreras said, “some will wake up and grow on, but what we have seen is you can root about 90%, and after winter one you’ll lose more than half, and the year after that half again.”

So how are most growing Styrax?

“Some folks have success with grafting, some are budding, and more recently there are plants in tissue culture — that’s the most effective way to bulk numbers fast,” Contreras said. Adam McClanahan , national field representative for Robinson Nursery said, “[Starway to Heaven®]’s not great from rooted cuttings. It can be finicky and difficult to take off. We had [sic] success with grafting, chip budding and tissue culture. Ideally, we’d prefer tissue culture. It overwinters well once it has a little root established.”

 “We do ours from soft wood cutting in summer,” Schmidt’s Meacham said. “It’s important to watch moisture levels over the first winter.”

What’s next

Looking toward the future, Schmidt is expanding the range of material used for crossing. “We are still doing crosses with the cultivars we have,” Meacham said, “but there are a great many species to consider not in cultivation, native to Asia or South and North America. We are looking at doing some crossing of those.”

What would be on his wish list? “There isn’t really a strong-growing upright, pink-flowered form; that’s something we would strive for. Also, deeper pink flowers in general, since some can fade in the sun.”

Contreras is looking closer to home for breeding alternatives to improve climate-readiness. “I have an idea I would like to cross Styrax japonicus with Styrax redivivus, the West Coast native — they really are bulletproof as far as drought goes.” Crossing a proven cultivar with a more resilient native is a strategy he’s seeing across genera.

Yet he also has his eye on Starway to Heaven® for its distinctive foliage. “I’m intrigued by Starway to Heaven® and hybridizing that with Swan Song. If we can change the game on its foliage that’d be intriguing.”

“I suspect breeding will look to find shapes other than weeping which have dark leaves and/or dark pink- or rose-colored flowers,” Zampini said.

Styrax cultivars can build a strong niche, Lewis said, possibly even competing in size and stature with ornamentals like Japanese maple. If cultivars can differentiate themselves with strong marketable qualities that the end consumer can easily see, such as Marley’s Pink, and have a reasonable growth rate for marketability.

The future is looking bright for snowbells.

“I think as more and more people begin to recognize the strong characteristics of Styrax, with the willingness to plant something different than the rest of the neighborhood, you will see it used more and more,” Lewis said.

“It needs greater exposure to architects, landscapers and end consumers. I feel there has been a lot more motivation on the market to expand the selections of Styrax. There’s probably under five Styrax cultivars that are players in the market, but the world has more crabapple cultivars than you could shake a stick at, so plant something that’s a little more unique and rewarding.”

At Robinson, “demand has been solid and continues to increase annually,” said McClanahan. “As more folks become familiar with and more professionals are using them in the landscape, we have confidence it will only continue to gain momentum.”

From the April 2025 issue of Digger magazine | Download PDF of article