Sniffing out osmanthus - Oregon Association of Nurseries

Transcription

Sniffing out osmanthus - Oregon Association of Nurseries
New leaves on Osmanthus heterophyllus
‘Goshiki’ emerge red and quickly turn
green. The green leaves are daubed with
spots of creamy white, gray-green and
yellow-green. Goshiki translates from
Japanese as “five colors.”
Photo courtesy of dennis’ 7 Dees
Sniffing out
osmanthus
These shrubs and trees have real appeal for their
compelling fragrance, hardiness and variegation
By Elizabeth Petersen
“Fragrance is king in a classical
Chinese garden,” explained Glin Varco,
director of horticulture at the Lan Su
Chinese Garden in Portland, Oregon.
It’s no wonder then that the plant
collection at Lan Su includes a significant assortment of evergreen osmanthus
shrubs and trees. All of them produce
enchantingly fragrant flowers — some in
spring, but most of them in fall or winter.
At Lan Su in early October, an
upright Osmanthus fragrans var. aurantiacus kicked off the fall bloom with
masses of delicate orange blooms.
The bloom of slow-growing O. fragrans was getting underway elsewhere
at Lan Su, too. Clusters of tiny white
blooms, redolent of ripe apricots or
peaches, danced among the small tree’s
dark green, glossy leaves.
Flowers from these attractive ever-
greens are so aromatic that they are
harvested and used to flavor tea, wine,
cakes and other delicacies. Traditional
Chinese medicine claims that antioxidants
in osmanthus can improve the complexion. The essence of osmanthus flowers is
also used to make fine perfume.
Big in China
There are 23 species of osmanthus
native to China, where the plants
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osmanthus
boast wide use and symbolic importance. They are associated with nobility,
and play a role in traditional Chinese
wedding ceremonies as a symbol of
true love and faithfulness.
But as garden and landscape plants
in the U.S., the attributes of osmanthus
are surprisingly underutilized. Despite
their hardiness and adaptability, their
evergreen foliage and exquisite fragrance, osmanthus does not have a
very significant market presence.
Arda Berryhill, owner of Berryhill
Nursery in Sherwood, Oregon, sells
liners and containers of several varieties
of osmanthus.
“I like the plant,” she said, “but they
are anything but hot sellers. O. delavayi
is the most popular, with osmarea (O. ×
burkwoodii) next.”
Some growers are enjoying good
luck with the genus, however.
Pam Snodgrass, owner of P&D
Nursery, a wholesale grower of broadleaf shrubs in Tualatin, Oregon, has
had better success with osmanthus. Her
nursery supplies O. delavayi and O. heterophyllus ‘Goshiki’ in #1 containers as
“move-up” material for other growers, #2
containers for retailers (“a nice size and
a decent price point”) and #5 containers
for the landscape industry.
“I love osmanthus,” Snodgrass said.
“It is a good plant for us. We sell out
across the board every year. We sell
quite a few to landscapers. It is easy to
talk people into osmanthus because they
are beautiful, tough as nails and drought
tolerant when established.”
Snodgrass recommended their use
as hedges or screens, and as stand-alone
specimens.
Variegated false holly (Osmanthus heterophyllus ‘Variegatus’) is an extremely
tough evergreen shrub. The bright cream-edged foliage holds up well in sun
or shade. Once it is well established, it will produce tiny — but powerfully
fragrant — flowers in fall. photo courtesy of monrovia
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Chris Steinke of Youngblood Nursery
in Salem, Oregon, agreed that osmanthus
is underappreciated by the public.
“We here at Youngblood Nursery
appreciate them, though. They are low
maintenance, and they don’t need as
much water as other shrubs we grow. All
varieties look good throughout the year.”
The three varieties grown at
Youngblood Nursery — ‘Goshiki’,
‘Purpurea’ and ‘Rotundifolia’ — sell
steadily, Steinke said, and demand has
been increasing for a few years now.
“Matter of fact, we have had more
demand for ‘Purpurea’ and ‘Rotundifolia’
than we can keep up with.”
Steinke sees great potential in the
genus: four more selections are “coming
down the line” at Youngblood, he said.
Youngblood’s expanded assortment
will include a few selections from the
The bright, year-round color of Osmanthus heterophyllus ‘Goshiki’ makes it
a great choice for landscapes in the Pacific Northwest. O. heterophyllus is
known for its wonderfully fragrant fall flowers, but this cultivar — at least
when young — does not flower. photo courtesy of monrovia
Great Plant Picks program, which
recommends plant varieties that thrive
in the Pacific Northwest. Five varieties
of osmanthus have made the GPP list
so far: O. delavayi, O. × burkwoodii,
O. ‘Goshiki’, O. h. ‘Purpureus’ and
O. h. ‘Variegatus’.
Osmanthus by the X’s and O’s
O. delavayi (sweet olive) drapes
neatly over large boulders in the entry
courtyard and one of the interior garden
rooms at Lan Su Chinese Garden. The
prolific spring bloomer “doesn’t pack the
(fragrance) punch” of the fall bloomers,
according to Varco.
O. delavayi has other strengths.
Leonard Foltz of Dancing Oaks in
Monmouth, Oregon, has found O. delavayi to be a good choice for an espalier
or a narrow spot in the garden. The elegant, classic combination of small, dark
green, evergreen leaves and clusters
of fragrant white flowers provide yearround interest. A slower grower than
O. × burkwoodii, O. delavayi can be
clipped into a hedge, allowed to grow
naturally or grown in a container.
O. delavayi gets 5–8 feet tall and
wide, is very easy to grow in conditions
as varied as full sun and deep shade,
and tolerates a range of soils. It is hardy
to USDA Zone 7.
O. × burkwoodii (hybrid sweet
olive) is another spring bloomer with
clusters of fragrant white flowers in
April. Although not grown at Lan Su,
O. × burkwoodii has plenty of attributes
to recommend it. Small, medium green,
leathery evergreen leaves maintain a
presence throughout the year, making
the tough shrub a good choice for privacy screens.
A cross between the Chinese O.
delavayi and the Turkish/Georgian O.
decorus, O. × burkwoodii can get fairly
large, 5–8 feet tall and wide. Adaptable
to sun and shade, sand and clay, O. ×
burkwoodii is drought tolerant when
established. It can even support climbing
clematis to extend its seasonal interest.
Foltz finds O. × burkwoodii to be
the most reliable, vigorous grower. “O.
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osmanthus
delavayi grows well in the ground,” he
said, “but it’s not as easy to strike roots or
to get established as O. × burkwoodii.”
“Burkwoodii makes a nice hedge,
although it can grow a little wild and
may benefit from some pruning to keep
it tidy,” Snodgrass said.
Both O. delavayi and O. × burkwoodii
are listed by Great Plant Picks as shrubs
that perform well in very heavy, dry shade.
O. heterophyllus is called “false holly”
because its leaves resemble spiky holly,
especially when young. Several varieties
offer an interesting assortment of choices.
They appeal mostly for their interesting
foliage and superior function, but their
flowers can be rather inconspicuous.
The most well known and widely
grown of the species — the “hands-down
best seller” at Youngblood Nursery — is
the hybrid ‘Goshiki’. The very slow-grow-
ing shrub boasts striking variegated foliage
that brightens dark spots in the garden.
Snodgrass recommends ‘Goshiki’ for
its colorful foliage, attractive habit and
tough constitution, requiring virtually no
maintenance. Although not a fragrant
bloomer, the color contrast of green, yellow and the reddish tint of new leaves
makes ‘Goshiki’ a popular plant that
“pops in the garden,” Snodgrass said.
Goshiki translates as “five-colored”
in Japanese and refers to cream, pink,
orange, yellow and white spots and
swirls found on every leaf.
A popular, multi-purpose plant,
‘Goshiki’ is useful as an informal, colorful
hedge that only gets about 4 feet tall; it
works well in containers too, according
to Foltz. Extremely tough and a little slow
to grow, ‘Goshiki’ presents no problems
with propagation, Snodgrass said.
Osmanthus yunnanensis, shown at the Lan Su Chinese Garden in Portland,
is a shrub or small tree native to the Yunnan district of China. It has highly
fragrant white blooms in the winter and grows slowly, reaching a mature
height of up to 10–13 feet. photo by curt kipp
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Rarities in the field
Other selections of osmanthus can
be found in the trade, but may deserve
production in larger numbers.
One of these, O. h. ‘Rotundifolius’,
holds forth at Lan Su, where its late fall/
early winter flowers fill the garden with
intense fragrance. The slow-growing
selection (usually about 5 feet tall and
wide) has unusual leathery leaves that
look like little, flat paddles.
“People like the rounded, undulating foliage,” Foltz said. “The plant grows
densely and keeps a nice rounded
shape, so it is a good choice for smaller
spaces. It is always good-looking and
happy in full sun to part shade.”
“‘Rotundifolia’ is more of a rarity,
not seen a lot,” Steinke said. “It seems
to be sought after by the designer who
wants something just a bit different, and
Blooming in April, the tubular white flowers of Osmanthus delavayi perfume
the garden. Adaptable and flexible, this evergreen shrub provides year-round
interest; it can be clipped to form a hedge or screen or left to grow naturally.
photo courtesy of monrovia
the garden center owner who has a penchant for the unusual.”
In Steinke’s experience, though,
‘Rotundifolia’ seems to be the hardest
to get to a sellable size. It needs time
to fill in, but it does have small, white
fragrant flowers.
Perhaps the most striking of the
selections at Lan Su is O. h. ‘Sasaba’, a
very slow-growing, upright plant. The
standout feature of this compact false
holly is its beautiful, albeit sharp, foliage. Very narrow, deeply lobed, verdant
green leaves are tipped with spikes and
held in erect clusters; the effect is gorgeous. Fragrant white flowers appear
later in the fall.
Youngblood Nursery now grows
‘Sasaba’ as well as O. h. ‘Ogon’. ‘Ogon’
takes the brightening effect of ‘Goshiki’
to new heights: golden foliage keeps
its color throughout the year. A dwarf
form that grows slowly to 4–5 feet with
a widely pyramidal shape, ‘Ogon’ produces fragrant flowers in fall.
Another variety found at Lan Su,
O. × fortunei produces extremely fragrant flowers. Its leathery, evergreen
leaves start out with somewhat toothed
edges, becoming smooth with age. The
drought-tolerant plant makes an excellent evergreen screen or hedge, and
will develop a large stature if allowed to
grow naturally.
Youngblood Nursery also grows O.
h. ‘Purpureus’, a purple-leaved selection
popular with East Coast garden centers,
according to Steinke.
O. yunnanensis, a native of southcentral China, thrives at Lan Su. Its
leaves are among the largest of the
genus. The British website Architectural
Plants claims it is “the most architectural
of the genus, a large-leafed, distinctive,
evergreen little tree (to 20 feet) that is
unaccountably rare.”
Elizabeth Petersen writes for the garden
industry and teaches SAT/ACT test prep
at www.satpreppdx.com. She can be
reached at gardenwrite@comcast.net or
satpreppdx@comcast.net.
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