Category Archives: Summer Color

summer interest inthe garden

Boehmeria platanifolia

Boehmeria platanifoliaThe longer we garden the more we appreciate both subtlety and contrast… especially when a plant makes you do a double take because of some extraordinary features. Boehmeria platanifolia is one of these plants: unique foliage, size, with late summer pale green flowers. This species of Boehmeria has large sycamore shaped green leaves (up to 5″) with serrated edges and covered with tiny hairs giving the plant a soft glow. The leaves attach to the sturdy stems with contrasting red petioles. Green tassel flowers emerge from the branch tips in August and continue to droop into the fall.

Boehemeria platanifolia performs best in partial shade, in a soil that is evenly moist. Established plants can grow to 5′ tall and 4′ wide. It is a Japanese member of the Nettle family, Urticaceae, and this particular species is quite hardy…reports say to zone 4, but we’ll play it safe in saying it will grow well in zones 5-8.

Combines well with Tricyrtis (toadliles), Begonia grandis (Hardy Begonia) and Leucoseptrum (Japanese Wood Mint) in the fall shade garden.

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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.

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Gentiana ‘True Blue’ PPAF

Blue. Not only blue, but ‘True Blue’… that is the name hybridizer Darrell Probst chose for his selection of this long blooming Gentian.

Here?s been our experience. This is the third year ?True Blue? has spent in our garden, and it seems quite happy where we planted it: at the top of a stone retaining wall, in well drained rich soil, in a partly sunny spot (4-6 hours a day).  Gentiana ‘True Blue’ begins to bloom by mid July and carries on through the summer heat into September. Our plants have only have grown to 12-15″ in height, although all the literature suggests it can grow to 2′ or more.  Darrell suggests that we plant this Gentian in a more fertile soil to attain full height, and I”m ready to find a few more spots in the garden that will accommodate this lovely specimen.The 2″ chalice shaped flowers face upward, catching the morning dew.

Hardiness range is USDA zones 3-8. Darrell shared in the comments box that the parents of this hybrid are of Japanese or Korean ancestry, perhaps G. makinoi, and not from more fussy alpine regions. All the more encouragement you need.

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Euphorbia ‘Ascot Rainbow’

Euphorbia 'Ascot Rainbow'Those of us in northern climates are suspicious when we’re told showy evergreen Euphorbia are hardy for us (zone 6), with good reason. Arctic winds and lack of snow cover often dessicate the foliage and those the early blooms. Well we’ve had mixed results with the fabulous Euphorbia ‘Ascot Rainbow’, and what we’ve learned is it’s all about siting. That being said, we’d grow this plant regardless of winter hardiness because it looks good for the entire growing season, from early spring into December.

Euphorbia ‘Ascot Rainbow’ is a selection of E. x martinii. It boasts beautiful gold and green variegated foliage tinged with coral red, especially on the new growth and when temps are cooler. Multiple red stemmed branches form 18-24″ mounds. Euphorbia ‘Ascot Rainbow’ blooms on new and old growth, with adorable variegated bracts exposing tiny red flowers. I’ll say this again, this plant looks fabulous the entire growing season here in New England, and because of this it is equally as wonderful in containers as it is in open ground.

Now in regards to siting: we used Ascot Rainbow in container plantings at an urban restaurant, where they looked so fabulous at the end of the winter  that we left them in for the spring display. Really! In this protected spot, surrounded by buildings radiating heat, the Euphorbs were quite happy. In open ground we’ve had mixed results. In a raised bed with good drainage the plants came through, although we had to cut back the sad looking evergreen foliage after the winter. Snow covered much of the ground during the winter of 2010 and 2012  and our plantings came through unscathed. The recommendation: good drainage, protection from wind,  in sun or partial shade.

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Plectranthus ‘Mona Lavender’

Plectranthus ‘Mona Lavender’ just beginning to bloom

Plectranthus is a large genus from South Africa, related to Coleus. This selection, ‘Mona Lavender’, was bred at Kirstenbosch Botanical Garden in Cape Town, S Africa in the 1990’s and was introduced into the US market by Ball Horticultural. Plectranthus ‘Mona Lavender’ is a stunning plant bearing dark green foliage with eggplant purple undersides. She teases you with an occasional bloom in summer months, but we have found here in southern New England that it is not until  late August when the real display begins. Multitudes of lavender throated flowers are held in upright spires providing a show that continues right until frost.

Grow Plectranthus ‘Mona Lavender’ in rich soil in sun or partial shade. Plants branch quickly when pinched, and this encourages a compact form. ‘Mona Lavender’ generally reach 18-24″ for us, but may get 2-3′ in a climate with a longer growing season. (Customers in Florida wholeheartedly give this plant a thumb’s up). We love using her in containers where her dark foliage adds contrast, and surprise from the late flush of blossoms. Alas she is only hardy to 35 degrees, so when frost is predicted, you may want to bring ‘Mona Lavender’ indoors. She might be very happy spending the winer on your sunny window sill.

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Pennisetum orientale ‘Karley Rose’

There are many forms of Fountain Grass out there, including some lovely selections that are only hardy in warm climates, such as P. setaceum and advena cultivars. One that we’ve been charmed by is this selection of Oriental Fountain Grass, Pennisetum orientale ‘Karley Rose’ . ‘Karley Rose’ begins sending forth it’s soft fuzzy plumes in June and carries on through October… that’s 5 months. ‘Karley Rose’, pretty enough for pots, is splendid planted in drifts, where it will dazzle and dance in the late day light.

‘Karley Rose’ forms clumps of slender green foliage which are about 2′ tall and wide.  3-4′ stalks bear smoky mauve pink plumes very early in the season. Horticultural literature states it is hardy in zones 6-9, but a number of our customers reported no losses in zone 5.  Give her a spot in full  sun, (sheprobably can take a little shade) and a soil that has good drainage. Pennisetum orientale ‘Karley Rose’ is a star candidate for xeriscaping, and would be great partnere dwith Euphorbia Helena’s Blush’, Sedum ‘Maestro’  and Calamintha nepetoides.

Chasmanthium latifolium ‘River Mist’

Chasmanthium latifolium ‘River Mist’ (image courtesy of Itsaul Plants)

Chasmanthium latifolium ‘River Mist’ is another plant whose charms are not revealed well in a photograph. This variegated selection of Northern Sea Oats, an American native grass with a bamboo likeness, has light and lovely white striped foliage/seed heads, and performs a graceful dance in the garden with any gentle breeze. It does particularly well in light shade and is stunning used en masse or as a vertical focal point in containers. The foliage forms clumps 12-15″ tall and 24″ wide. 30″ stalks bear the showy striped seed heads in late summer and early fall. Take advantage of siting ‘River Mist’ where backlighting will add drama to the display, or use it against a darker shades to set off the white striping.

The objection some may have to this attractive native grass is that it does self-sow, though perhaps not as vigorously as the straight species, and the seedlings are usually not variegated. What one should do to avoid the unwanted seedlings is to cut the attractive flowering stalks for flower arrangements.  Plants are tough and hardy in zones 4-9, making them suitable for gardens throughout much of the U.S.

Aralia cordata ‘Sun King’

Aralia cordata 'Sun King'Need a bold, deer resistant plant for the shade garden? Consider Aralia cordata’Sun King‘, tropical in appearance, but a really good option for cold climate gardens.  Hardy in zones 3-8, this choice selection of Spikenard is slow at first, but once established, forms a 3′ x 3′ mound of broad compound brilliant yellow foliage. It retains a golden glow throughout the summer as long as it gets 2-3 hours of sunlight. Sturdy 3-4′ stalks emerge in mid August, each topped with a small fireworks display of white flowers. Dark fruit follow the floral display. When the show is over, ‘Sun King’ will need a rest and will die back with the first hard frost.

Aralia cordata ‘Sun King’ grows best in a rich but well drained soil that has available moisture during the growing season. Good companion plants, besides Hosta, include Actaea ‘Hillside Black Beauty’, Fargesia scabrida, Kirengeshoma palmata and Hakonechloa macro .

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Thalictrum x ‘Splendide’

Giant MeadowrueThere are some plants which you have to meet in person, as photographs just can’t convey their personality or presence. Thalictrum ‘Splendide’, a new giant Meadowrue from French breeder Thierry Delabroye, is one such specimen. Vigorous stalks shoot to the sky  ( 6-9′ in height), are heavily branched and bear clouds of dime sized lavender blossoms in such volume, the bouquets may indeed become top heavy, so added support by staking is a good idea. This airy display begins in June and continues for months (yes, months) into September.

Good news for cold climate gardeners: Thalictrum ‘Splendide’ is quite hardy, wintering over in zones as cold as 4 (some even say zone 3). It is a hybrid of T. delavayi planand it is sterile, which accounts for its long season of flower production. Like all Meadowrue, ‘Splendide’ enjoys a rich moist soil in sun or partial shade. Use ‘Splendide’ in the company of other big perennials and shrubs that also thrive in somewhat moist conditions, such as Eupatorium maculatum, Persicaria polymorpha, Hibiscus coccineus or Hydrangea cultivars. Don’t let ‘Splendide’s size intimdate you. It?s refreshing to have perennials in the garden that you can look up to.

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