Sometimes amazing things happen when you cross similar plants from different regions: Digitalis (European Foxglove) and Isoplexis (Canary Island Foxglove. The result: beautiful perpetual blooming 3′ spires of tubular flowers, which are colored sunset coral in bud and then open, exposing yellow throats with hints of apple green. This particular selection, ‘Flame’, is the first of the Illumination series introduced by Charles Valin which won the prestigious award of Best in Show at the Chelsea Flower Show in 2012.
Last year we grew Digiplexis ‘Flame’ in a large pot. It began to bloom in early June and carried on for months, well into September. The blossoms are sterile, which tricks the plants to be constantly in flower. We brought the container into the cool greenhouse to winter over and it’s back up and about to start the show all over again. This year we’ve also planted it in our garden beds for the constant color it provides. We envision it as the vertical complement to Dahlias and Summer Phlox in a sunny, enriched , well drained border which gets an average amount of irrigation. I can attest that the hummingbirds were regular visitors, as were bees and butterflies, and I suspect it is deer resistant as well.
Because Digiplexis inherited its hardiness genes from its Canary Island parent, it will only winter over outdoors in zones 8-10, (although one of our customers bragged to me the other day that hers wintered over outdoors in a protected spot in zone 7). Dig up the roots after the first frost, as you would a Dahlia and store in a cool spot that stays above freezing for the winter. Gardeners in warmer winter climates don’t have to worry about this, and I can only imagine the display in their garden year after year!
Clockwise from left: Sempervivum ‘Pacific Blue Ice’, Sedum ‘Angelina’, Semeprvivum ‘Carmen’, Sedum album ‘Coral Carpet’, Sempervivum ‘Topaz’, and Sedum stefco
It is early April here in New England, and as the snow retreats, a walk about the garden reveals color from unexpected plants…winter hardy succulents. Yes the early crocus and snowdrops are showing off, but they will come and go quickly. Since we’re still flirting with frosts and will not begin to see rich greens and bright pastels until the end of the month, the delicious burgundy and coral tones taken on by many hardy Sempervivum and Sedum provide a different color palette. These hardy succulents may not grab your attention when plant shopping, since many gardeners aren’t selecting plants at nurseries until warmer temperatures prevail. By late spring, the intense foliage hues change to more muted blue green and olive coloring. And of course, there are many more brightly colored blossoms to distract us.
If you’re taking a survey of your gardens right now, consider where you can use the rich, changing colors and textures that winter hardy succulents provide. They require minimal care and look good year round, especially the “evergreen” forms. Many are hardy into zone 3 plus are deer and rabbit resistant. They ask only for sun and good drainage, and can winter over admirably in containers as well.
The receding snow (we had over 3′ at one point) did not harm Sempervivum ‘Carmen’ in the least.
Anemone sylvestris, is simply lovely and so innocent-looking, but perhaps it should be introduced to you as a potential ground cover. Commonly known as Snowdrop Anemone, this super hardy gem begins blooming in mid-late spring, producing nodding buds which open to 5 petaled white blossoms centered with a ring of yellow stamens. The blossoms, buoyantly dance on 12-18” stems, which are good for cutting, emit a soft early spring fragrance. Although it is a European native, it looks right at home in naturalistic landscapes here in the US, spreading vigorously by rhizomes, and it is very effective for disguising early spring bulb foliage. The wooly seed heads that develop once the blossoms fade add visual interest later in the summer. Occasionally, a small flush of flowering in takes place early fall.
Anemone sylvestris is happiest in a rich well drained soil, and is hardy in zones 4-8. It is not fond of extreme heat, so best to hold off in southern gardens. There are no serious insect or disease problems and it is deer resistant.
Let us reacquaint you with an underutilized evergreen plant for cold climates.
Bold, colorful, architectural evergreen foliage. Dramatic creamy nodding lily flowers in early summer. Deer and rabbit resistant, it grows in poor and dry soils, and is perfectly hardy in zones 4-9. Why oh why don’t more landscapers and gardeners plant Yucca filamentosa ‘Color Guard’?
Yucca ‘Color Guard’ provides northern gardeners with a brightly colored vertical accent for mixed border plantings. Plants attain a foliage height of 24″, and when ‘Color Guard’ chooses to bloom, those creamy white lilies are held on 4-5′ tall towering stalks. Hummingbirds almost swoon over the plants in pour garden. We have it planted in a hot dry bed, with Acanthus hungaricus, Crambe maritima Euphorbia ‘Ascot Rainbow’ and dwarf evergreens.
Tricyrtis hirta ‘Tojen’
A must have plant for the late summer/fall shade garden is Tricyrtis hirta, commonly known as Japanese Orchid or Toad Lily. There are numerous cultivars; one I am especially fond of is the selection ’Tojen’ , with has unspotted lavender, orchid like flowers held in loose sprays on sturdy stems above large lush foliage.
Toad Lilies enjoys a rich welled drained soil that stays adequately moist in the growing season. ’Tojen’ is more forgiving of drier soils than other cultivars, but I recommended keeping the soil irrigated to keep plants at their best in late summer when they really show off. ‘Tojen‘ grows 24-30” tall by 30” wide and is hardy in zones 5-8. Some great companion plants are Kirengeshoma palmata, Begonia grandis and late blooming Hosta such as ’Red October’.
One look at Kniphofia and you might be able to guess its native habitat is Africa. Commonly called Torch Lilies, or Red Hot Pokers if you prefer, this member of Xanthorrhoeaceae family (not Liliacea, the Lily family) forms upright grass like foliage clumps from which rise spires of beautiful multi-toned tubular flowers beloved by bees, butterflies and hummingbirds. There are over 70 species, some of which are not hardy in northern climates. Most species bloom during northern hemisphere summers, but there are a few forms that will bloom when summer arrives in S. Africa, that is to say, December.
Recently Terra Nova Nurseries introduced a line of dwarf hybrid Kniphofia which they affectionately called the Popsicle Series. These dwarf selections have foliage that grows 12-15″ tall, with flower stems reaching 18-24″ depending on the cultivar. Blooming begins in mid July (for us), with flowering stalks continue to emerge right through September. We planted a half dozen of the form ‘Creamsicle‘ last summer, with its bright to pastel yellow orange coloring and they wintered over well, so this year we tried 2 new selections… ’Orange Vanilla Popsicle‘, with a toffee orange to cream tones and ‘Pineapple Popsicle‘ with a tart pastel lemon to chartreuse coloring.
Plant Kniphofia in a soil with good winter drainage and in full sun. It provides a 2 exclamation point to beds when used in small groups, or would be stunning used en masse in a larger setting. Kniphofia is a great companion to Euphorbia such as Ascot Rainbow and almost any Sedum. It can be sited in the foreground of a mixed shrub border…we have it coming up through a sea of steel blue Shore Juniper.
One more thing you might appreciate: deer do not like it!
Kniphofia ‘Pineapple Popsicle’
Kniphofia ‘Orange Vanilla Popsicle’
Persicaria polymorpha at dusk, photo by Paul Clancy
Mention the name Persicaria in horticulture circles, and you may raise a few eyebrows. Persicaria has a very bad cousin: Polygonum cuspidatum, commonly known as Japanese Knotweed or Running Bamboo (but it is not a bamboo!), and this cousin can spread DREADFULLY. But please read on…
Persicaria polymorpha is commonly called Giant Fleece Flower, and this common name describes it well. Within a few seasons, Persicaria polymorpha will reach 5′, maybe 6′ tall and form imposing clumps, increasing in width each season to 6′ or more. Talk about taking up space! In June and July, white Astilbe like plumes adorn the plant and the blooms seem to last and last. This is a great plant for a long distance view (think about its size and white color) and is memorable when viewed in the early evening light.
Here are the facts: Giant Fleece Flower likes average soil, or moist soil, or even very dry soil once established. It loves full sun but will grow in partial shade. It is a bold perennial and and adds contrast to the finer textured plants in your garden. Like Baptisia, it is one of the first herbaceous plants to attain good height in the spring. It is deer resistant and long lived. I have yet to discover seedlings about, although it can be propagated by seed. Persicaria polymorpha is hardy in zones 4-9.
Consider Persicaria polymorpha when you are in need of a big, bold, hardy, long blooming, deer resistant plant.
Growing Lavender en masse here in the northeast has often been a risky thing to do. Lavender would suffer winter damage, and we would often find we had to replace plants here and there every winter. The good news is that after this recent cruel winter which caused more than its share of plant casualties, a new Lavender introduction came through unscathed. Lavandula ‘Phenomenal’, in fact, is looking pretty phenomenal.
Here’s the data. ‘Phenomenal’ was introduced by Peace Tree Farm Nursery in PA, after the folks there observed it for years in their trial beds. ‘Phenomenal’ tolerated extreme heat and humidity in summer, making it a good choice for hot summer areas, and was resistant to root diseases which often plague lavenders where winters are cold and wet. ‘Phenomenal’ begins blooming in late spring and carries on through July, with masses of intoxicatingly fragrant lavender blue flowers. Plants grow slowly at first, but reach large proportions
24″ tall and 36″ wide in several years time. Deer and rabbit resistant, it also attracts butterflies and grows best in full sun and well drained soil. Plants are super hardy too,
wintering over in zones 4-8.
Looking for a bold foliage plant that is cold hardy through zone 5, deer resistant and is one of the first to show signs of life in the spring? Meet this form of Variegated Russian Comfrey, a naturally occurring hybrid of S. officinale x S. asperum. ‘Axminster Gold’ will form 18-24″ tall robust clumps of 14″ creamy yellow edged lanceolate leaves, which grow 2-3′ wide. In late spring and early summer, pink and lavender “bluebell-like” flowers will bloom on nodding 4′ stems, attracting a myriad of butterflies. Once the blooming period is over, do remove the aging stalks to promote fresh foliar growth. Last summer we saw ‘Axminster Gold’ in a garden paired with Periscaria ‘Firetails’, and want to duplicate this combination.
Grow ‘Axminster Gold’ in full sun or partial shade in a soil that is rich and somewhat moisture retentive. ‘Axminster Gold’ can be quite vigorous once established in the garden but is somewhat scarce in the trade due to propagating difficulty. For some reason plants propagated from root cuttings will be solid green , so divisions must be taken from the central crown in order to ensure you’ll be getting the gold variegation.
A wintry mix of weather blew into town this week, but Ligularia ‘Last Dance’ didn’t want the waltz to end. This recent introduction from Itsaul Plants looked smart all season with glossy bronze purple round foliage accented by slightly pointed lobes. To add Halloween contrast, it sent forth bright yellow composite flowers in October and is still blooming away as of 11/14. Hardy and tropical looking…hmm. First disclaimer…it did winter over in our zone 6 garden last year, but during the coldest period we were blanketed with snow. Ligularia x ‘Last Dance’ is a hybrid of Ligularia (Farfugium) hiberniflora and Farfugium japonicum, two species from Japan and Taiwan, but the Farfugium japonicum can’t be trusted in zones colder than 7.
Ligularia ‘Last Dance’ is being marketed with plant tags saying it is hardy into zone 4. I’m thinking this is a stretch. Reports from commercial growers say it is growing and wintering in Zeeland, Michigan (Zone 6) and Philadelphia (Zone 7). If you do want to grow this for its end of the season burst of color, here is the data: Foliage height is about 12″ high, and can grow to 2-3′ wide. Yellow blossoms are held on 1-2′ stems. It does well in sun or partial shade in a moist soil, but seems as happy in average conditions.
I think this season I will put down a winter mulch to protect my investment. Should it prove not to be zone 6 hardy, I say it should get 100 points for being a stunning container plant. Would love to hear from anyone else who is growing Ligularia ‘Last Dance’.