Category Archives: Summer Color

summer interest inthe garden

September Report: Successful Containers

New England’s weather challenges even the most experienced gardener. The summer of 2013 certainly gave this gardener a dose of humble pie. Spring arrived late but was quite lovely for several weeks. June was cool and adequately moist (some folks in western New England were deluged with rain, but we were happy here with what we received. July was tropical. Hot, humid, humid, did I say humid? And there are plants that loved the tropical weather: Colocasia, Coleus Papyrus, Canna. Unfortunatley I hadn’t planned on hot humid weather, so I didn’t plant many of them this year. No this year I couldn’t plant enough succulents; in the ground, in containers, in vertical gardens. It could have been a better summer for growing them, but they managed to carry on sullenly and perked up when August proved to be cool and dry. And now we are here, at the end of the season, to judge which of the containers held up the best over the 3 month period. (See the June article: The Before Pictures  for evidence of how containers transformed.)

The Cissus had to be cut back. Begonia ‘Concorde  has resented the recent chilly nights. Still this has been an easy shade loving combo which I would repeat.

Coleus ‘Odalisque’ dominated this planter, Begonia thurstonii has held its own, but can’t say the same for the Begonia ‘Elegance’ (there is a glimpse of what’s left of it). Our Begonia boliviensis hybrids and and most of our Fuchsia really pooped out early this year.

This partial shade planter wasn’t shown in the June post, but it has been quite lovely all summer. Plectranthus ‘Velvet Elvis’ is really starting to bloom now. Why don’t people grow more of the interesting trailing ivies?

I was a little disappointed that the Xanthosoma didn’t explode with growth, but the gentle green foliage of Pelargonium tomentosum looked fresh all summer, and I love to rub its leaves as I walk by.

Once the Eucomis bloomed, that was that, and then the Lantana montevidensis with its profusion of lavender flowers on wiry stems took over. Oxalis triangularis never disappoints, and Tradescantia ‘Blue Suefilled in nicely.

We have planted this classic stone bowl with succulents for the past few years, but this year’s growth was the least impressive. Not bad, but look what it did last year.

Only the Senecio cylindricus put on growth. I think all the other succulents just sat there. At least they didn’t melt.

This bowl was planted around the 4th of July, with a mix of hardy and tender plants. The Senecio ‘Blazing Glory’  is beginning to bloom with it’s bright orange buttons. I like the hardy Sedum ‘Turkish Delight’ but next time would leave out the Sedum ‘Xenox’.

We moved our famous River Pot to a more prominent spot. What wouldn’t look great in this pot?

The vertical garden is still looking sweet. The Crassula schmidtii has been in bloom for weeks, and the Echeveria ‘Atlantis’ continues to want to send up flowers.  I made several  versions of these vertical gardens, experimenting with just hardy plants and mixing lots of different tender succulents. Some succulents grew well despite the weather, others were more temperamental.

This container continued to inspire customers to replicate it all summer. The grouping is Echeverias ‘Afterglow’ and ‘Lola’, Phormium ‘Pink Stripe’, Saxifraga ‘Maroon Beauty’, and silvery Dichondra.

What was your summer weather like and  how did your containers fare this year?

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Euphorbia corollata

Euphorbia corollata

I think I know the reason why few people grow this easy care, refreshing native plant, commonly called Prairie Baby’s Breath: plants, even young seedlings, transplant poorly. The happiest plants have planted themselves, like this clump that adorns our front walk entry right now; it was sown in situ. Of course, you need to have a mother plant nearby to have these babies come up on their on accord, and that’s a “chicken or the egg” dilemma. We always have a few potted plants here at Avant Gardens but because they usually look weak and spindly, they are not an easy sell….unless you happen to visit our nursery and gardens in August. Now, everyone marvels at this “different baby’s breath” when they pass by.

Once established, Euphorbia corollata asks for little but sunshine and well drained soil. It begins to bloom heavily in mid July and carries the show through the month of August. I haven’t tried it as a cut flower, (it is a spurge and has that milky sap), but maybe I should experiment with sealing the stems with a flame, which will prevent that sap from poisoning the vase water. Perhaps it would be prudent to stress that some people are very sensitive to Euphorbia sap and can get serious skin irritations when exposed to it. Fortunately for me it has never been a problem.

Euphorbia corollata is hardy in zones 4-7. We planted it in our gardens more than 20 years ago, and it is still there, a testimonial to it’s longevity, often popping in new spots, especially well drained pockets. Should it sow where you don’t want it, just pull it out. In addition to being quite attractive to beneficial insects, such as bees and wasps, it isn’t a plant deer or rabbits will likely munch on, since it is poisonous if ingested.

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Calamintha nepeta ssp. nepeta

Calamintha nepeta ssp. nepeta

At last, we found an image that displays Lesser Calamint,Calamintha nepeta ssp. nepeta , in a flattering light. Perhaps that’s why more people don’t grow it: it doesn’t always photograph well, and it’s not in bloom when everyone is plant shopping in April and May. It has been one of our “go to” plants when designing sunny gardens for years. Here’s why.

Calamintha nepeta ssp. nepeta has grown well in our garden for the past 18 years. Yes, the same specimens, planted in 1995, return each year true to form. In spring they present as tidy little subshrubs (no, it does not spread by runners) with mint scented, slightly shiny leaves.  In July (June in warmer zones) sturdy 18″ stems bearing racemes of airy blue tinted white flowers appear, creating a cloud like effect for the front of the border and accenting any plant around it, and it is especially complimentary to roses. The blossoming continues into October, when the flowers take on blue tones with cooler temperatures.  Calamintha nepeta ssp. nepeta is a primo plant for attracting bees, butterflies and beneficial insects. This form of Lesser Calamint has rarely self sown in our gardens, unlike the very similar  Calamintha nepeta ‘White Cloud’, which seems to happily self sow. You might like having babies, or not. You decide.

As mentioned before, this is a reliable perennial (18 years and still going strong) for us here in southern New England. Calamintha nepeta ssp. nepeta performs well whether we  are having a hot dry summer or a cool moist one. It likes a soil that is well drained, but does not need or want lots of fertilizer. I know it will be this reliable in zones 5-7, but would be interested in hearing if folks are growing it successfully in zones 8 and 9.  Its tidy form and endless flowering means it can be combined with so many other plants, depending on your color scheme, but consider using it with Asclepias tuberosa, Sedum ‘Maestro’, Echinacea ‘Fatal Attraction’ or Caryopteris for strong summer interest.

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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.