Category Archives: Trees and Shrubs

woody plants, trees and shrubs

Salix chaenomeloides ‘Mt Aso’

Salix chaenomeloides ‘Mt Aso’

Even though the sun was shining today, I was still feeling discouraged by yesterday’s snowfall. As I went out to make sure all the greenhouses were properly closed for the day I caught a glimpse of pink, shimmering in the late afternoon light. Greeting me with optimistic charm was the pink pussy willow Salix chaenomeloides ‘Mt Aso’ . I had planted one last fall, and it was set off quite dramatically by the freshly fallen snow.

Salix chaenomeloides is the Latin name for giant pussy willow. It is native to Japan but adapts well to a wide range of garden situations including sandy, average and even quite moist soil. Plants can get quite large, 15′ or more, but in order to have a steady supply of branches which will bear the rosy red catkins (which are male flowers by the way, are you surprised?) you should coppice (cut back to 1-2′ above ground) every 2 or 3 years. This will keep plant size a more reasonable 6-8′, and provide you with an ample supply of cut branches for winter arrangements

Salix chaenomeloides ‘Mt Aso’ is hardy to zone 4. You know you want one. Go for it. I guarantee that if you plant  ‘Mt. Aso’ this year, you’ll be smiling next March, even if “return to winter” weather tends to make you grumpy.

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Stewartia pseudocamellia var koreana

Stewartia_koreana_flower500It would be a difficult choice, but if I had to select one deciduous tree for my garden, it would have to be the Korean form of Stewartia pseudocamellia, and this is why: here is a small tree (25-30′) with striking interest in all 4 seasons. In winter, a mature Stewartia pseudocamellia var koreana shows off its handsome narrow pyramidal shape, which broadens a bit with age, and lovely exfoliating bark, exposing shades of tan, pink and gray. In spring, it breaks anew with fresh dark green elliptical leaves, arranged alternately along its branches. In early summer, lovely 3″ white camellia like flowers are displayed. Each blossom only lasts a short time, but there are so many produced over several weeks that you never feel it is not performing.  In autumn, Stewartia pseudocamellia is truly mesmerizing, flashing you with foliage in shades of brilliant red, orange, gold and green.Stewartia_koreana_fall

Stewartia pseudocamellia is native to Japan and Korea, and the Korean form is generally considered a bit hardier. The Korean form tends to have a more narrow pyramidal shape than the species found in Japan. In its native habitat, it is found growing with Clethra barbinervis and Enkianthus campanulatus, both exceptional large shrubs or small trees, with multi season interest.  Stewartia pseudacamellia var. koreana grows best in sun or partial shade in a humus rich but well drained soil, out of strong wind. It is hardy to minus 20F and grows well in zones 5-8.

stewartia_bark

 

Viburnum dilatatum ‘Michael Dodge’

Viburnum dilatatum ‘Michael Dodge’

Meet ‘Michael Dodge‘, a golden berried hybrid of Linden Viburnum. He is a cheerful fellow,  who shows off in late spring with a bevy of white lacey flowers and then later develops clusters of showy yellow fruit, which is a sight in our garden right now. The birds are leaving the fruit alone, but that is fine with me because the fruit bearing stems are perfect additions to autumn floral arrangements.

I received a nice note from the plant’s breeder, Mr. Michael Dodge himself.  He informed me that he made a deliberate cross between V. dilatatum and V. d. Xanthocarpum in hopes of getting a larger fruited yellow form in his days working at Wintherthur in Delaware. Mr. Dodge left Winterthur not long after, but was notified that there were some very nice clones from the seedlings he planted. Harold Bruce, the garden curator at that time, named the best yellow fruited clone after him.

Viburnun dilatatum is of Asian ancestry and although it looks perfectly at home in a naturalistic border, it is not as favored by birds and wildlife (plant V. dentatum and other native viburnum species). What it does do is provide dramatic color in the  autumn landscape.  Something you should note is that in order for a good berry set you need another cultivar of V. dilatatum nearby. This may sound confusing, so I should clarify. You should plant a different clone for good cross pollination, and Mr Dodge specifically recommends Viburnum dilatatum ‘Cardinal Candy‘, who will put on a show of its own with bright red fruit.

Viburnum dilatatum ‘Michael Dodge will grow 8-10′ tall and wide. He is not fussy about soil, but will certainly appreciate a fertile loam and grows best in full sun or partial shade. ‘Michael Dodge  is hardy through zone 5.

Caryopteris x ‘White Surprise’ PPAF

Caryopteris 'White Surprise'

Caryopteris ‘White Surprise’

What’s not to love? For three years now,  this white variegated form of Blue Mist Shrub has been a stunning plant in one of our sunny raised beds, providing great form, foliage and easy performance despite dry conditions and humid heat. ‘White Surprise’,  a sport of Caryopteris  ‘Heavenly Blue’, becomes a handsome 3′ x 3′ mound of aromatic white edged foliage, topped with contrasting medium blue flowers from mid-summer through September. Of particular note is how well the white edged foliage resists leaf scorch. Bees and butterflies flock to the whorled clusters of blossoms. It pairs well with so many other long season interest plants, such as Echinacea ‘Virgin’, Alstroemeria ‘Mauve Majesty and Sedum ‘Maestro’ .

Grow Caryopteris ‘White Surprise’ in well drained soil in full. It is hardy in zones 5-9, although there may be more winter die back in colder climates. Not a problem though: just cut it back hard in mid spring. Caryopteris is deer resistant, and it’s lovely white/green/blue coloring is a cooling sight in the hot summer garden.

Cornus kousa ‘Wolf Eyes’

Cornus kousa 'Wolf Eyes'As I get older I am so appreciative of all the trees Chris and I have planted over the years, often as little twigs which we acquired from specialty mail order nurseries or the Arboretum Plant Sale. One that has become our favorite is Cornus kousa ‘Wolf Eyes’,  a variegated form of Chinese or Japanese Dogwood.

Wolf Eye’s‘ was selected at Manor View Farm in Monkton MD, and has been declared by plant expert Paul Capiello to be one of the best variegated forms of Cornus kousa. Eventual height depends on siting and hardiness zone (hardy in zones 5-9), but reports range from 10-20′ with equal spread. Our ‘Wolf Eyes’ is a now 12′ x 10′ specimen. The gray green leaves are delicately rimmed with white, and will curl slightly as protective measure when cited in hot sun. What we find remarkable is how well the white “flowers” (really showy bracts) stand out against the white variegation, when it “blooms” in June. As the flowers fade, curious edible fruit begin to form. They look like red raspberries on short sticks when they ripen in early fall. Fall foliage color takes on pinkish red tints.

Site ‘Wolf Eyes’ in full or half day sun, and, no surprise, in a rich well drained but adequately moist soil. Water well in dry spells., but excessive overhead watering from a sprinkler or irrigation system  can cause spotting of the foliage. C. kousa is resistant to Anthracnose, but too much exposure to wetness for extended periods will cause fungal problems.

Rhododendron diversipilosum ‘Milky Way’

Rhododendron diversipilosum 'Milky Way'

Image courtesy of Briggs Propagators

We thought you might enjoy the subtle charm of this hardy little known Rhododendron (perhaps nomenclature is its problem) . Commonly called Labrador Tea, formerly classified in the genus Ledum, and then later named R. tomentosum, there’s been obvious confusion when gardeners are seeking information. ‘Milky Way’ is a superior clone selected by Steve Hootman. In mid April, it produces trusses of small white starry flowers, which allude to its cultivar name. Fine textured evergreen foliage is small narrow and olive green.

Rhododendron diversipilosum ‘Milky Way’ is quite cold hardy, growing well in zones 3-6. It can take poor soil conditions but will be happiest if given a well drained soil with humus and regular moisture in sun or partial shade. Plants grow to 3′ in height and up to 5′ in width. It would be a great addition to a rock garden planted with early spring Narcissus, Hellebores and Veronica ‘Georgia Blue’.

Spirea thunbergii ‘Ogon’

Spirea thunbergii ‘Ogon’, in fall

Had to include this plant portrait now because this baby’s fall color is on fire! We had wanted to portray Spirea thunbergii ‘Ogon‘ (a.k.a ‘Mellow Yellow’) in a blog post last spring, but there are always so many plants vying for our attention at that time of year. Not that this Spirea doesn’t. As a matter of fact, it is one plant we never tire of, and include it in many of our landscape installation projects.

Unlike most Spirea, this species has narrow willow like foliage that emerges a bright lemon yellow in early mid spring. White flowers adorn the arching branches just prior, and as the leaves unfurl. Although they are sweet enough, they aren’t why you should grow this shrub. Grow this Spirea for the texture and color the foliage provides year round, and which as you can see here, is an especially grand finale of volatile color in November.

Spirea thunbergii ‘Ogon’ is hardy to minus 20F (zone 5), and grows quickly to a height and width of 4-5′. It’s very happy in full sun, but grows well in partial shade, and seems to withstand poor dry soil conditions without hindering its performance. Like all Spirea it can be cut back hard in the spring if you choose to keep it shorter, but you’ll sacrifice the flowers. We could go on and on about which plants to use in combination with ‘Ogon’, but the list is practically endless. May we suggest Acanthus hungaricus, Fothergilla ‘Blue Shadow’, Japanese maples of any form, Geranium ‘Rozanne’.…..(we could go on and on).

Fothergilla x ‘Blue Shadow’

With Halloween just weeks away, it’s fitting that we take a look at a very colorful Witch Alder. The Witch Alders, as you may guess, are closely related to Witch Hazels, and are native to the southeastern US.  They are multi season plants, with honey scented white bottle brush flowers emerging in early spring (just before and as the plants leaf out), plus attractive form and outstanding fall color. One we are pleased to be growing is Fothergilla x ‘Blue Shadow’ notable for the lovely glaucous blue foliage it displays all summer.

Fothergilla x ‘Blue Shadow’ was discovered by Gary Handy of Boring OR, when he noticed this very blue leaved sport on another fine cultivar, Fothergilla ‘Mt Airy’. It’s a vigorous but compact grower, with an upright habit at first, then becoming thicker with age, and finally achieving 5-6′ in height and width. ‘Blue Shadow’ grows well in full sun or partial shade, prefers a reasonably moist but well drained slightly acidic soil, and is quite hardy in zones 4-8. It can be used as a focal point, or planted en masse at the edge of a woodland. So many plants would make great companions. For spring interest, pair with dwarf Rhododendrons; for summer, Hydrangea quercifolia ‘Peewee’ , and for fall the golden Leucosceptrum  and Carex ‘Blue Bunny’ to compliment ‘Blue Shadow’s technicolor display.

Lespedeza thunbergii ‘Gibraltar’

Bush clover in blossom waves
without spilling
a drop of dew
—- Matsuo Basho

If you had to choose one plant to fill your late summer garden, you might consider the lovely Japanese Bush Clover, Lespedeza thunbergii ‘Gibraltar’. This selection was discovered by the accomplished plantsman, Bill Frederick, at Gibraltar, one of the duPont family estates in Wilmington, Delaware.  We have to admit ‘Gibraltar’ is a big show-off, quickly growing to 5-6′ tall and in just a few years occupying an 8-10 sq. ft. area quite easily. It loves a sunny spot and is hardy in zones 5-9.

 Lespedeza thunbergii ‘Gibraltar’ is in the legume family, and this means it does not require a rich soil, but prefers one that is a lean and well drained. To manage its size and form, you should cut the woody stalks hard to the ground in early spring. This may seem alarming at first, but Bush Clover blooms on new growth and  the full height will be attained by mid summer. A bevy of cascading branches adorned by an abundance of purple pink pea blossoms will add eye catching color from late August through September.

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Albizia julibrissin ‘Summer Chocolate’

Purple Mimosa TreePerhaps the most asked about plant in our garden right now is this purple leaved silk tree or mimosa, with it’s stunning chocolate purple fernlike foliage. The followup question is often, “but is it hardy” to which we answer, “yes, but…”. (Recommended hardiness zones are zones  (6b) 7-10, and our garden is definitely zone 6a.)

This is the scoop based on our experience. Albizia julibrissin ‘Summer Chocolate’ is a fast growing ornamental tree or large shrub, introduced to the US market roughly 10 years ago. True, it is less hardy than the more common green leaved forms. In 2005, our first attempt to establish this tree failed. We didn’t site it well.  We planted ‘Summer Chocolate’ in a spot where we thought it would look outstanding, but alas, it was the lowest spot on our property and the soil remains too wet there over the winter.  Initially we were resigned to growing it as a container subject, but were reminded by the old adage: if a plant doesn’t grow well in one spot, try another, and then another.

Good drainage usually is key in wintering over borderline hardy plants. We planted the next specimen in well drained soil in front of a south facing stone wall, and are now enjoying this beauty for the 3rd year in a row. It did get some die back after the winter of 2009-2010, but broke growth along the lower trunk and quickly grew to 6′ that year. We won’t expect it to reach full height or width, and don’t really care.  Tropical appearing chocolate colored foliage with a shrublike habit suits us just fine.

Those of you in milder winter areas (zones 7-10) can expect this tree to reach 20′ in stature and spread, with silky pink puffs of flowers in summer.  Gardeners in zones colder than 6 might consider growing ‘Summer Chocolate’ as a stunning container specimen. The plant, pot and all, can easily be moved into an unheated garage or other protected spot once it goes dormant in late autumn.