This palette of white-blooming trees and shrubs provides strong design options
White blooming plants can provide balance in the garden or landscape, and landscape designers’ plans.
“I do find clients who have an approach of a modern or more formalistic garden, that tend to go for white [blooming plants],” said Roxy Olsson, a landscape designer at Farmington Gardens (Beaverton, Oregon). “They’ll say, ‘I want modern with white blooming hydrangea,’ or ‘I like white and black,’ or ‘I like these colors, and white will be one of them.’”
White blooming plants can also be planted for a spiritual or mystical sensibility to the garden, and even as a focal point in a gathering of containers, said Kip Nordstrom, garden designer and owner of Hearth n’ Soul (Lake Oswego, Oregon).
There are so many valuable selections of white-blooming plants, from annuals to vines and even trees. In Part 1 of this series (see Digger, April 2020), the focus was on tender plants and hydrangeas. Here, in Part 2, we continue the exploration of top-quality plants named by growers and designers as strong selections, this time focusing on woody plants.
Camellia and Gardenia
“There are so many white flowering camellias that people don’t know about that are just easier than Camellia japonica,” said Brie Arthur, garden designer, horticulturist and author out of Raleigh-Durham, North Carolina. There are varieties and species that show brilliant white blooms from September to the end of May.
C. japonica ‘Sea Foam’ is one of her favorites — a vigorous grower to 6–8 feet by 5–6 feet with pure white double flowers in winter through spring, paired with contrasting large deep-green leaves. Another vigorous grower, C. oleifera (tea-oil camellia) is a fall bloomer, but it comes from high elevations, so it is reliably hardy to USDA Hardiness Zone 6a. It has incredible fragrance and a 20-foot by 10-foot habit.
One of Arthur’s favorite white-blooming plants is an “older gem,” Gardenia jasminoides ‘Michael’. At 5 feet tall, it never needs pruning. It’s a completely reliable plant that she laments has been overlooked by a nursery industry focused on introducing smaller jasmine that are ill-suited to survive fluctuating climate conditions.
Nordstrom specifically installs the 9-foot by 9-foot evergreen Camellia sasanqua ‘Setsugekka’ close to houses, as a foundation plant, for the show it provides in winter when the garden is quieter. But, this plant is suffused with semi-double, ruffled flowers with bright golden stamens.
Arthur could recommend so many viburnum, but if she had to live with only two, the first would be Viburnum plicatum f. plicatum ‘Popcorn’ (Japanese snowball), and the second would be V. bitchiuense (Bitchiu viburnum).
‘Popcorn’ is another oldie-but-goody, according to Arthur. A slower grower, by 10 years old it has only reached 6-foot by 4-foot in her yard. It needs no pruning and no water once established. “It has big white flowers — a reliable bloomer — that are appropriate to the stature of the plant,” she said.
The lesser-known species V. bitchiuense is beautiful in early spring and has a dark burgundy fall color. As partly deciduous, it doesn’t drop its leaves until the new foliage grows.
“This is one of those plants that I don’t have to do anything to and looks good year-round,” Arthur said. “It has a tight growing habit, doesn’t need watering once established and is good for property borders [because of its size].”
For years, a staple in Nordstrom’s designs was V. plicatum f. tomentosum ‘Summer Snowflake’. With its 15-foot mature height, it can be trained like a small tree for a small space. “It blooms profusely in spring, and will throw additional flowers in summer, although not as profusely,” she said.
“Trees can get big, even a small one is 30 feet,” Nordstrom said. So usually, if she wants something smaller, she uses shrubs and trains them into a small tree. But she makes an exception for Stewartia pseudocamellia (Japanese stewartia), a Great Plant Pick. It is one of her favorite trees for all of its four-season interest; including cup-shaped white flowers, fall-colored leaves, winter seeds, decorative branching and a patchwork bark of pinks, reds, greens and grays.
“[The bark] is like the finest of fabrics,” said P. Annie Kirk, owner and landscape designer at Red Bird Restorative Gardens (Woodburn, Oregon).
According to Arthur, the evergreen 20-foot Magnolia grandiflora ‘Kay Parris’ is like M. grandiflora ‘TMGH’ (Alta® southern magnolia), but with an improved growing habit. “So it’s appropriate for street trees and small neighborhood lots,” she said. It is especially good for a mixed property border paired with, for instance, Thuja and Viburnum.
Nordstrom recommends M. grandiflora ‘Little Gem’, one of the smallest magnolia varieties for its fragrant 4-inch flowers that provides a big display in spring. She also gives Prunus serrulata ‘Mt Fuji’ center stage in her landscape designs because it presents a spectacular flower display in spring, when the semi-double flowers cover the branches of the umbrella-shaped 20-foot by 25-foot tree.
Lastly, she recommends the 15-20 foot Cornus ‘Kn30 8’ VENUS® (Cornus kousa ‘Chinensis’ × Cornus nuttalii ‘Goldspot’ × Cornus kousa ‘Rosea’) with its giant 6-inch flowers that takes 20 years to reach a mature size.
Olsson explains that Farmington Gardens puts out rows of VENUS, and when people walk through the nursery, and customers put their hands up to compare the size with the large blooms. VENUS can compete for showiness with magnolia as a centerpiece and within 10 years it only gets 20–25 feet and is bigger and more rounded as the canopy fills out.
Notable high drought tolerance
Grace Dinsdale, founder and manager at Blooming Nursery (Cornelius, Oregon), has planted Salvia apiana (white sage) in a few places and never watered it. “They get quite big, 7–8 feet with the bloom,” she said. The bush is about 4–5 feet tall. “It’s happiest in a high drought situation,” and even works at the seaside where there are salty sprays.
Ribes sanguineum ‘Oregon Snowflake’ (white flowering currant), developed recently by Ryan Contreras at Oregon State University, is 4–5 feet tall with pendulous white flowers. “Lots of them, just covered [with flowers],” she said. It blooms for a long period, late winter through spring, and is very drought tolerant and white. Plus, hummingbirds are attracted to it.
Convolvulus cneorum (silverbush) thrives with little water. Otherwise, it is vulnerable to stem rot. The combination of silvery foliage and white flowers — with a rose reverse on the petals — forms 1–2-foot mounding bushes with blooms from late spring through summer, according to Dinsdale. It works in containers and attracts pollinators.
“People don’t think about azalea and fragrance,” Olsson said. But, Azalea ‘Fragrant Star’ (deciduous azalea) is highly fragrant with blooms clustered to create a pompon effect. It is shade-tolerant and good for entryways and darker spaces. An East Coast native, Fothergilla gardenii (dwarf fothergilla) has bottle brush-type, exploding blooms on bare stems when the leaves are starting to bloom. “It’s good for a part-shade environment and is typically found in coniferous forests, so can pair well with old growth,” Olsson said. Besides its dwarf 34- to 36-inch size, the leaves have a blue sheen and turn colors in fall.
Another East Coast native, the 3–4 feet tall Philadelphus × virginalis ‘Miniature Snowflake’ (dwarf Eastern mock orange), has multilayered blooms that start out as showy white buds with no green bract, that add color and texture. “The buds look like polka dots before the flowers, which are really fragrant,” Olsson said. The drought-tolerant, sun-loving shrub can be more in the background or combined with evergreen, conifers or shrubs like evergreen huckleberry.
Rosa rugosa ‘Blanc Double de Coubert’ (rugosa rose) is fragrant, naturalistic and produces more of a thicket, which is great for beds, “They have an amazing seasonal interest,” Olsson said. Usually blooming through late fall, it provides fall color and then red rose hips in winter. They are multifunctional, with flowers that can be used for potpourri and rose hips for simple syrup.
Clethra alnifolia ‘Hummingbird’ (sweet pepperbush), at 4–5 feet, stays small and has “beautifully spired white blooms and can be used as background plant with conifers,” Olsson said. It’s fragrant, attracts pollinators, and in fall turns a vivid yellow. “Combining that with a rounded or upright spruce captures a more Rocky Mountain feel,” Olsson said, “giving more of natural look.” As it ages, the bark can be smooth even in the wintertime.
‘Hummingbird’ is also one of Nordstrom’s all-time favorites. For outstanding fragrance, she also uses Philadelphus ‘Belle Etoile’ (Mock Orange) for its compact 5–6-foot size and abundance of flowers in midsummer.
A little larger, Arbutus unedo ‘Compacta’ (dwarf strawberry tree) has been a go-to choice for her when it is trained as a small tree. Periodically, she needs to get a new one because it gets overwatered. But for its size — maturing at 10 feet — and four-season interest, it is multifunctal in the garden.
Closer to the ground, she uses Rosa ‘Flower Carpet White’, which she can keep a tidy 2–3 feet tall without a lot of work. “If I want a rose on a bank, I use this,” she said.
And for shade, the evergreen 4–6 feet Loropetalum chinense ‘Emerald Snow’ (Chinese fringe flower) has the solid structural element she likes to build designs, with the bonus of heavy blooming in spring and continued sporadic blooms during summer.
Three more recently-added plants to her list of favorite white bloomers include Osmanthus delavayi (Delavey osmanthus), a 6–8-foot evergreen shrub with slim, arching branches and blooms from winter to spring bloomer; Deutzia gracilis ‘Duncan’ (Chardonnay Pearls®), which brightens with its chartreuse foliage once the blooms have faded in spring; and the dwarf and fragrant D. gracilis ‘Nikko’ (Slender Deutzia).
“I do adore white astilbe in a dark and shady grotto,” said Kirk. “It looks like lightbulbs, with a Dr. Seuss quality.” She names 30-inch Astilbe arendsii ‘Bridal Veil’ (Bridal Veil false spirea) for its pure white color. “I’m a snob about pure white,” Kirk said. “For me, it’s an incredibly powerful color.”
The ruggedness of the newer 8–10 foot Loropetalum chinense ‘Snow Panda’ (Chinese fringe flower) also appeals, especially contrasting with its delicate flower, according to Kirk. Philadelphus lewisii (Lewis’ mock-orange) — which she just transplanted two from an old to a new garden — and (Philadelphus × virginalis ‘Miniature Snowflake’) are fragrant and not fussy like gardenia. They have a taller stature and a lovely sophisticated flower head.
For around the patio, Justin Hancock, senior director of marketing at Monrovia Nursery Company (Dayton, Oregon) recommends the tropical Jasminum sambac ‘Monhariklia’ (Summer Soul® Arabian jasmine). It has incredibly fragrant double flowers and if kept watered and fertilized, it will bloom all summer long. Bring it in the winter and make jasmine tea from it!
Prunus laurocerasus ‘Chestnut Hill’ (Chesnut Hill cherry laurel) only gets to 4 feet tall and wide, Hancock said. It is a workhorse shrub that includes fragrant spring flowers. “Cherry laurel falls into the gas station category, it’s so easy to grow.”
Also with fragrance, Abelia grandiflora ‘Lucky Lots’ is evergreen, with variegated foliage and a tidy 2½-foot-tall habit. “You can tuck it into any sunny spot, it is good for pollinators and once established, has pretty good drought tolerance,” Hancock said.
For brightening shady areas, Pieris japonica ‘River Run’ (Enchanted Forest® River Nymph™) produces a “crazy number of flowers,” Hancock said. It also lasts longer compared with other Pieris, on a 5½-by-5½-foot plant.
For all situations, moist or dry, sun or shade, tall or short, there is a white blooming plant to balance and contrast with other plants in the landscape or garden.
Tracy Ilene Miller is a freelance writer and editor who covers several topics, including gardening. She can be reached at firstname.lastname@example.org.