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.
Sedum sieboldii on the left, next to Sedum cauticola
Hmm….October Daphne. Well, it’s a bit of a stretch to say this delightful sedum is reminiscent of a Daphne, but if I use my imagination I might convince myself. Perhaps there is a bit of a resemblance to one of the low creeping forms. Regardless of whether the common name is misleading, little Sedum sieboldii adds a dose of autumn color to the late season garden, with clusters of rosy pink flowers at the tips of arching stems, clothed with pink and apricot tinted blue green scalloped foliage.
Botanical nomenclature now wants to classify this form of Stonecrop as Hylotelephium, but for the sake of common knowledge let’s continue here using the genus Sedum. Sedum sieboldii begins the spring season as a tidy rosette of almost turquoise fleshy scalloped leaves that develop a lovely wine red edge. The form and foliage work well all season and then informally transform in early fall, when the stems begin to extend, flower and develop October color. It is super hardy (we’re talking zone 3 here). It is most often used as a rockery subject, tucked into crevices where it remains quite happy, but we’ve left it outdoors in frost tolerant pots and it returns in the spring unfazed. Obviously Sedum sieboldii likes well drained soil, but we’ve found it to be quite forgiving of average soil conditions.
Bush clover in blossom waves
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.
Just the common name, Toad Lily, sparks curiosity and invites close inspection. The delicate blossoms of this attractive cultivar of Tricyrtis formosana resemble small orchids and have distinctive spotting on the blue-violet petals. Flowering interest begins in early August, but the golden yellow foliage adds color early in the season. Plants are stoloniferous, forming small clumps 12″ high, making it suitable for the front of a border. Small Hosta such as ‘Wogon Gold’ and Japanese Forest Grass Hakonachloa macra make excellent companions.
Grow Toad Lilies in a soil that stays uniformly moist, yet well drained. The foliage tips will brown if the soil becomes too dry, and although not lethal, will make the plants less attractive. Tricyrtis ‘Gates of Heaven’are unappetizing to deer, and are hardy through zone 5-9.
Waxbells, as Kirengeshoma palmata is commonly called, is an herbaceous perennial with a shrublike habit that adds striking foliage and sweet pale yellow flowers to the late summer shade garden. The flowering display begins in mid August and continues through September. Earlier in the season, the large maple like leaves add bold contrast to the many delicate textures that predominate in our beds. Kirengeshoma may be a little late to break dormancy in the spring, since the new shoots are quite frost sensitive, but once it finally feels the weather is safe, it quickly grows to a height of 4-5′. With time, plants form large clumps 3-6′ across. And if you need another big plus, the deer dislike it.
Kirengeshoma is native to the woodlands and low mountain regions of Japan and Korea, which accounts for its hardiness through zone 5. It grows best in a rich, slightly acidic soil that is moist yet well drained. Propagate by seed or by division in early spring. We like to associate Kirengeshoma with blue and gold Hosta, such as ‘Deep Blue Sea’ and ‘Brother Stephan’ as well as late blooming Actaea ‘Hillside Black Beauty’ .
Sometimes your garden needs something tall, something blue. The abundant display of summer perennials laden with yellow daisy-like flowers begs for plant selections which offer dark contrast.
A “temperennial” here in zone 6, Tall Mexican Petunia won’t winter over outdoors for us, but it certainly will in zones 8-10. Still, we always make room for it in our gardens and also use it in container combinations where the tall 3-4′ purple stalks are clothed with narrow dark green purple tinted foliage. The continuous display of violet blue funnel shaped flowers extend on short stems from the leaf axils, and attract bees, butterflies and hummingbirds.
Ruellia ‘Purple Showers’ does enjoy evenly moist soil, and will even grow well along a pond?s edge or in low standing water, a situation that can be challenging. This does not mean it won?t grow in average soil conditions, for it will, but it does not want to fry. Southern nursery catalogs list Ruellia as an evergreen shrub. We suspect Ruellia may become territorial in warm climates, and should be planted where its vigor is an asset.
Not all Persicaria deserve persecution. Persicaria amplexicalis ‘Golden Arrow’ is not only one of the “good” members of the Polygonum (Knotweed) family, it is an extremely handsome and versatile perennial. The first thing you should note is the golden green lance shaped foliage, which is attractive all season. Big plus. In mid summer ‘Golden Arrow’ begins to display an array of ruby colored spiky tassels, which account for its common names: Firetail and Red Bistort. The flower show continues into September, and both flowers and foliage combine beautifully with the many late summer yellow composites, as well as pink or blue/violet asters, and of course all the Salvia.
Leaf color is brightest yellow when grown in full sun, but ‘Golden Arrow’ will require a little extra moisture if the area is on the dry side. Otherwise, grow it in a well drained soil in half day sun, where the golden yellow will tint slightly more green. Foliage height reaches 18-24″, with flowers adding another 6″ or so to the plant’s stature. The spread of each plant depends on age and culture, but expect Persicaria ‘Golden Arrow’ to eventually take up 2 sq. ft. It grows well in a wide range of hardiness zones from relatively mild zone 9 through a quite chilly zone 5.