“Ground-cover for dry shade“ is the most common refrain when I ask people if they are familiar with Epimediums. (No, is another common answer!) Although some species do spread and make great drought-tolerant ground covers, the vast majority of species are clump forming and all of them prefer adequate moisture and well-drained, humus-rich soils. Those that most often make the ground-cover cut– E. ×rubrum, E. ×versicolor ‘Sulphureum’ and E. ×perralchicum ‘Frohnleiten’– do so for several reasons. They are drought-tolerant after they become established, short in stature, with good quality foliage. They have also been on the market for many years. Hopefully this list of some uncommon ground-cover types will encourage you to expand your horizons and try some of the lesser known, but still useful, beautiful and spreading forms of Epimedium.
All Epimediums grow by woody rhizomes that live just below the soil surface. The woodiness of these rhizomes or “underground stems” accounts for their relatively slow growing nature (as compared to herbaceous perennials). It also makes them very tough (as does the fact that the stem is protected underground). Some species–grandiflorum, diphyllum and fargesii for example- have very short, incremental rhizome growth each year, so that over time, the stems of the plant form a woody underground “knot”. These types make an ever-enlarging clump over time, but essentially occupy the same real estate for many years. Generally the kinds whose annual rhizome growth can be measured in inches, rather than fractions of an inch, are considered to be spreading types or “ground-covers”. Here I focus on some of the less commonly used spreading types.
E. macrosepalum ‘Sweet Rachel’ is a charming, very low-growing, spreader. Recently introduced to cultivation in the U.S., this selection is the result of a National Arboretum plant exploration of the southeast coastal region of Russia. I value this cultivar mostly for its evergreen foliage that displays some of the best fall color in all of Epimedium-land. Heart shaped, leathery leaves cover the ground at only about 3-5″ high. Limey green in spring, they turn a beautiful burgundy-red in fall when grown in bright shade or a bit of sun. Although a shy bloomer, this species has beautiful, large (for an Epimedium) flowers that I liken to eggs on an Easter egg hunt– an extra special treat to discover. Their large, rounded lavender-pink sepals arch back while the spur tips and the rim of the flower cup stretch forward and brighten to white. Their very thin rhizomes grow 4-8+” annually here in Massachusetts.
E. ×versicolor ‘Neosulphureum’ is often overlooked in the shadow of it’s well known sister plant ‘Sulphureum’. It does not spread as quickly, (the rhizomes grow only 2-4″ a year), but nevertheless, it forms a nice tight ground cover that just travels at a slower pace. A hearty bloomer, it is surprisingly showy in the shade, with its soft yellow flowers shining brightly against the delicately bronzed semi-evergreen spring leaflets. It makes a very classy addition to the woodland garden.
Many customers ask me for a white flowering spreader, but very few Epimediums fit that bill. Epimedium sempervirens ‘Okuda’s White’ is one of them. George Schenk introduced this unusual and rare cultivar from Japan in the 1970’s. Although most sempervirens cultivars are clump forming, this gem spreads 4-6″ a year with large, pristine white flowers against light green leaves, a very fresh-looking combination. This very low growing, semi-evergreen groundcover only reaches 5-8″ in height.
If you want a wonderfully warm pop of bright spring color, then you can’t do better than E. ×versicolor ‘Cupreum’. It is one of my very favorites. Cheerful pinkish-salmon flowers with a soft yellow cup hover above red-flushed leaflets, spider-veined in lime-green in springtime. In fall, the angular leaflets turn a distinctive and attractive blackish maroon. Plant it against a solid colored background, such as the white of a birch trunk, or the grey of a granite boulder, to best show the cacophony of spring color of this handsome variety. Semi-spreading at 4-5″ per year, with foliage 9-12″ tall. In good soil and bright shade, you can expect your clump to increase to a diameter of 2′ in 4-5 years.
From Iran comes the drought-tolerant, evergreen E. pinnatum ssp. pinnatum. Its foliage has an attractive reddish-blush in both spring and fall. This subspecies has far more textural foliage than E. pinnatum ssp. colchicum, with 9 leaflets per leaf instead of 3-5. Its bright lemon-yellow flowers erupt from the blush of the newly emerging foliage in spring to brighten any space. It is a good spreader with 8″ long rhizomes.
One of my favorite deciduous spreaders is E. grandiflorum f. flavescens ‘Chocolate Lace’. The new foliage looks like molten dark chocolate- with just a hint of red– against the tracings of its green veins. It makes an excellent backdrop for late blooming Narcissus such as ‘Thalia’. It is also spectacular when paired with blue-foliaged Hosta sp. in the garden, as are many Epimediums with dark spring foliage. 10″ tall in bloom, I consider it a “semi” spreader with rhizomes extending only 2-4” annually.
I hope this inspires you to try something new this season. All of the above described plants are uncommon in the trade.
As always I look forward to serving you– our loyal and enthusiastic customers. Thank you for your patronage and for helping to preserve, appreciate and perpetuate Barrenworts, Bishop’s Caps and Fairywings.
Owner- Garden Vision Epimediums