July 2014 Plant Profile: Hydrangea integrifolia

July 1st, 2014 by Soest Gardener, Riz Reyes
Photo courtesy of Richie Steffen/Great Plant Picks

Photo courtesy of Richie Steffen/Great Plant Picks

An evergreen hydrangea?!!  You betcha!

There are very few evergreen vines for gardeners in the Pacific Northwest, but this gorgeous gem from Asia is  becoming more readily available and it’s simply one of the coolest flowers you’ll ever get to witness opening.

From plump, peony-like buds, they begin to slowly crack open, a froth of fertile flowers begin to form and over the course of a few days, a flat umbel “lacecap” begins to form. People will begin to believe that it’s actually a hydrangea!

Hydrangea integrifolia is quite slow to establish (and re-establish, as we’ve learned after moving it to its new location at CUH three years ago) and may not even flower for the first few years of its life. Once it does, it puts on quite a show each summer. Dark green, glossy foliage remains year round. It’s a clinging plant that forms aerial roots on its stems. The aerial roots attach to a rough surface such as the bark of a tree or rough stucco wall; they don’t form tendrils or long whip-like shoots that wrap around supports so you have to carefully train them until they take hold. You could also let it sprawl on the ground as a ground-cover plant in a woodland garden.

They grow best in a protected spot in the garden such as a shady north-facing wall (such as our specimen here at the Center for Urban Horticulture), but they’re also quite at home tumbling over a stone wall in full sun with regular irrigation during the summer months.

Common Name:  Evergreen Climbing Hydrangea
Location: Center for Urban Horticulture – Miller Library North Foundation Bed
Origin: Taiwan/Philippines
Height and Spread: Can get 40′ tall and about 20′ wide
Bloom Time: Late June – July

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June 2014 Plant Profile: Philadelphus lewisii

June 3rd, 2014 by Soest Gardener, Riz Reyes

Philadelphus lewisii portrait 1The beginning of June boasts boisterous and abundant blooms and this native shrub is no exception. Starting in late May, an otherwise nondescript shrub begins to draw attention as masses of single white flowers suddenly begin to pop open creating a blizzard of deliciously scented clusters that cover a straggly shrub from top to bottom.

 

P. lewisii growing in the upland forest restoration site out in UBNA.

P. lewisii growing in the upland forest restoration site out in UBNA.

Found in open forests in low-mid elevations, Philadelphus lewisii is highly adaptable to the garden where it becomes a large shrub and requires only well-drained soil, moderate moisture, and full sun to part shade. It seems to tolerate competition from other plants very well, but requires some pruning to keep its size in check and to remove dead or non-productive  wood.

A established specimen in full bloom along the entrance into UBNA

A established specimen in full bloom along the entrance into UBNA

Philadelphus lewisii portrait 2

 

Common Name:  Lewis’s Mock Orange
Location: Union Bay Natural Area
Origin: Pacific NW Native
Height and Spread: 6-7′ tall and about 5-7′ wide
Bloom/Fruit Time: Late May – Early July

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May 2014 Plant Profile: Paeonia suffruticosa (Rockii Group)

May 6th, 2014 by Soest Gardener, Riz Reyes

Paeonia rockii type Joseph Rock’s Peony has been prized by gardeners and avid collectors for decades. Botanist and  plant explorer Joseph Rock earned the honor of having this exquisite flower named after him.

Peonies are divided into two basic types; the bush or herbaceous peony and the so-called tree peony. With similar flowers, the main difference between the two are their bloom times and their growth habit. Herbaceous peonies die back down to the ground each winter and bloom later in the season (May-June) whereas the tree peony, which isn’t really a tree, is more like a shrub with stems and branches that do not die back to the ground and flower mostly in May. Paeonia rockii is a tree peony.

Tree peonies are long-lived shrubs with exquisite flowers, but they take careful placement and a lot of patience until they’re well established.

They are best planted in the autumn so they are able to start forming new roots over the winter and it’s critical that they are planted in a location with full/part sun, well drained soil, good air circulation, and protected from strong winds that could damage the brittle branches. They can take several years to get established to consistently bloom each year and they also resent being transplanted.

Paeonia rockii

 

 

Common Name:  Joseph Rock’s Tree Peony
Location: Pacific Connections – China Entry
Origin: Gansu, China
Height and Spread: 6-8′ tall and about 5-7′ wide
Bloom/Fruit Time: Early-Mid May

 

A few selections of P. rockii can also be found growing at the Seattle Chinese Garden.

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April 2014 Plant Profile: Convallaria majalis ‘Striatum’

April 3rd, 2014 by Soest Gardener, Riz Reyes

Spring flowers are in abundance in April, but very few possess the charm and delightful scent of the infamous lily-of-the-valley. Known to be a thug in the garden once established, a variegated selection appeared that seemed to not grow as quickly. Still quick to spread in rich, moist soil and capable of competing with neighboring plants, the thin yellow striping along the leaf is quite unusual and can light up shady areas both before, during and after bloom.  The only caveat to growing this plant is its tendency to revert back to all-green foliage. Once this is encountered, simply yank out the green reversions to maintain excellent foliage color.

 

Common Name:  Variegated Lily-of-the-Valley
Location: Soest Garden Bed 7
Origin: Garden Origin
Height and Spread: 6-8″ tall and can spread forming patches in the garden.
Bloom/Fruit Time: April-May

 

 

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March 2014 Plant Profile: Stewartia sinensis

March 10th, 2014 by Soest Gardener, Riz Reyes
Photo by Mitch Evans

Photo by Mitch Evans

It may seem odd that we’re profiling a plant we currently don’t have yet at UWBG, but soon everyone will be able to see it in a very prominent spot at the Center for Urban Horticulture. After over 10 years in its place, the 2nd of two Parrotia persica (Persian Ironwood) in the Soest Garden will be removed to make room for a new tree that will take its place for the next 10 year cycle to cast part shade in Bed 2. Curation has selected the exquisite and rare Stewartia sinensis.

Many keen gardeners and horticulturists are familiar with the more common Stewartia pseudocamellia and the stunning bark of S. monodelpha. This Chinese stewartia seems to have been overlooked in the trade as descriptions state that the flowers are a hair smaller than that of S. pseudocamellia and monodelpha and the fact that it may be less hardy than the two species may also have contributed to its status as a collector’s item destined mainly for taxonomic collections.  It has the same exquisite white blooms with the yellow stamens and the trunk of this small tree is truly exceptional with pretty peeling bark and a magnificent marbling pattern as the plant ages.

Be on the lookout for this stunning species. It will be years until it casts the kind of shade the underplantings of herbaceous perennials prefer, but the eventual effect will be quite dramatic.

 

 

 

 

Common Name:  Chinese Stewartia
Location: Soest Garden Bed 2
Origin: Central China
Height and Spread: 20-25′ high x 15-20′ wide
Bloom/Fruit Time: June-July

 

 

 

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February 2014 Plant Profile: Helleborus x ballardiae Gold Collection® Merlin

February 4th, 2014 by Soest Gardener, Riz Reyes

Helleborus x MerlinHellebores are very popular winter-blooming perennials, and plant breeders are responding to the high demand for easy maintenance and colorful blooms during the gloomiest time of the year. The Gold Collection® is an assortment of species and modern hybrids selected for vigorous growth and prolific blossoms year after year. ‘Merlin,’ a Ballardiae hybrids (H. niger x H. lividus), is simply magical: it opens as a soft pink with a deeper pink reverse and a hint of lime green. As the flower ages, the blooms age to a richer deep pink and hold on for many weeks. The foliage on ‘Merlin’ is exquisite, with a hint of marbled variegation on tough, clean leaves.

 

Skagit Gardens in Mt. Vernon, WA kindly donated a batch of Helleborus x ballardiae Gold Collection® ‘Merlin’ to UW Botanic Gardens,  and the plants have done well for us. They’re exceptional in the garden, but also in containers for those who don’t have much space. Helleborus x Merlin 2

 

 

 

 

 

Common Name: Hellebore hybrid
Location: Entry Triangle Bed Entry along NE 41st St.
Origin: Garden Origin.
Height and Spread: 10-12″ high x 18″ wide
Bloom/Fruit Time: December-March

 

Helleborus x Merlin Habit

 

 

 

 

 

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January 2014 Plant Profile: Cupressus macrocarpa ‘Goldcrest’

January 6th, 2014 by Soest Gardener, Riz Reyes

Cupressus WG 1A striking addition to any landscape, this golden Monterey Cypress is quite popular and widely available in nurseries and garden centers. ‘Goldcrest’ is noted for its narrow, upright habit and exquisitely bright color; it fits into many different planting situations especially in smaller spaces.

The caveat to this beauty is its semi-hardiness in the Pacific Northwest. It requires a warm spot in the garden or it is best confined to a container planting that could be moved during a hard, cold winter. Most plants sold in garden centers are small, immature trees with very tender, needle-like foliage, and have a wonderful citrus scent when rubbed. They’re wonderful as a vertical accent in a container and are frequently sold decorated with ornaments during the holiday season.

They should be grown in full sun and have well draining soil. Once established, they are quite drought tolerant and often they turn slightly orange or light brown during the winter time, resuming chartreuse coloration once the weather warms in spring.

Cupressus WG close up

Common Name: Goldcrest Monterey Cypress
Location: Containers in Fragrance Garden
Origin: Garden Origin. Original species is native to the central California coast, USA.
Height and Spread: 6-7′ high x 18-24″ wide
Bloom/Fruit Time: N/A

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December 2013 Plant Profile: Gaultheria procumbens

December 2nd, 2013 by Soest Gardener, Riz Reyes

Gaultheria procumbens 1This low growing, creeping shrub often gets overlooked throughout most of the year, but its vibrant fruit and evergreen foliage make it a stunning addition to the winter garden, particularly in containers. The Wintergreen grows via shallow underground rhizomes and like most plants in the Ericaceae, it prefers acidic soils and because of its diminutive size, grows best in mostly sunny and exposed sites.

 

Gaultheria procumbens comboAmerican Wintergreen is best utilized in container plantings here in the Pacific Northwest as large patches of it in the garden are rarely encountered. It can be a tricky plant to get established in the garden and requires regular watering initially, but looks to be drought tolerant once it gets going.

As a container plant, the lovely (and edible) fruit are closely admired and last for many weeks. The fruit itself is actually a dry capsule and it’s the fleshy red calyx that surrounds it that looks like the fruit. When crushed, it has a minty aroma.

Common Name: Teaberry, American Wintergreen
Location: Containers by the commons and Merrill Hall
Origin: Eastern North American
Height and Spread: 3-8″ high x 10-12″ wide
Bloom/Fruit Time: September-March

 

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November 2013 Plant Profile: Camellia sasanqua ‘Setsugekka’

November 4th, 2013 by Soest Gardener, Riz Reyes

Camellia 2After a tremendous autumn display, the show continues in the landscape with wonderful fall and winter blooming plants that take center stage. This lovely selection of the fall/winter blooming Camellia sasanqua is highly coveted by garden designers for its glossy, dark green, evergreen foliage and simple flowers that do not leave a horrible mess once they’re through flowering.

‘Setsugekka’ has lovely pure white flowers with stunning yellow stamens that begin blooming in late October. It has a soft, earthy scent to its flowers and it has somewhat of a free and open habit that lends itself to being trained up against a wall as an espalier that provides a dark green background to others plants during the spring and summer months when its not blooming.

Camellia 1

Common Name: Fall-Blooming Camellia
Location: Fragrance Garden/NHS Hall Bed
Origin: Garden Origin
Height and Spread: 10-15′ high x 7′ wide
Bloom Time: October-February

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October 2013 Plant Profile: Hypericum Hypearls™

October 1st, 2013 by Soest Gardener, Riz Reyes

Hypericum 3Since our sample plants arrived three years ago from Blooms of Bressingham, this series of hybrid St. John’s Wort has really impressed us with their vigor, beauty, and reliability out in the garden.  These short shrubs are wonderful in bedding; not only are their showy yellow flowers attractive, it’s the fruit on these tidy plants that are the main draw.

Luminous pink to captivating corals, they often will be blooming and fruiting at the same time making them exquisite in floral arrangements. Even the ripened black fruit remain intact and are quite ornamental.

 

 

Hypericum 4

Hypericum Hypearls™ Olivia with Erigeron ‘Prosperity’ poking through

Hypericum 1

Hypericum Hypearls™ Renu

Hypericum 2

Hypericum Hypearls™ Renu with older fruit

Common Name: Hybrid St. John’s Wort
Location: Blooms of Bressingham Plant Trials
Origin: Garden Origin
Height and Spread: 2-3′ high x 3″ wide
Bloom/Fruit Time: Mid-June-Frost

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