Epimedium (Fairy Wing)

Epimedium are members of the barberry family which includes such other familiar garden plants as Mahonia (lumped by some into Berberis), Berberis, Podophyllum (mayapple), and Vancouveria.

Epimediums are known by several common names such as fairy wings, bishop's hat, and our personal favorite, horny goat weed. In Asian cultures, epimediums are used as herbal medicines to stimulate androgen hormones and therefore enhance sexual desire, erectile dysfunction, and to provide energy. This use was reportedly discovered after a farmer noticed goats which grazed on epimediums became much more sexually active. It is with mixed feelings that one passes bushels of dried epimedium roots in a roadside market on the way to a high peak in Asia...we'm sure they provided much enjoyment for the indulging parties, but at great expense to the preservation of many of these species.

In the late Professor William Stearn's first epimedium monograph in 1938 (updated just before his death in 2001), only 21 species were known.  Even as late as the early 1990s only a handful of these known species were represented in cultivation by living specimens.  As we would soon discover, far less than half of the epimedium species had even been discovered or named. 

Few genera of plants have seen such a dramatic increase in new species, primarily thanks to the work of  Mikinori Ogisu of Japan and Darrell Probst of Massachusetts.  Most of the epimedium species discovered and introduced in the 1990s were due to the work of the tireless Ogisu. 

Mikinori Ogisu's discoveries include Epimedium campanulatum (1996), Epimedium chlorandrum (1997), Epimedium dolichostemon (1993), Epimedium flavum (1995), Epimedium fangii (1995), Epimedium franchetii (1996), Epimedium ilicifolium (1998), Epimedium latisepalum (1993), Epimedium ogisui (1993), Epimedium mikinorii (1998), Epimedium rhizomatosum (1998), and previously named species that were not in cultivation such as Epimedium brevicornu, Epimedium ecalcaratum (1991), Epimedium fargesii, Epimedium lishihchenii (1997), Epimedium pauciflorum, and Epimedium platypetalum.

Darrell Probst's introductions include Epimedium brachyrrhizum (1997), Epimedium dewuense (2003), Epimedium epsteinii (1997), Epimedium myrianthum (1998), and the previously described Epimedium sutchuenense which he introduced to cultivation.  Many yet to be published species from his work are in the pipeline. 

As of 2008, our collection had swelled to 49 of the currently named 54 species, along with most of the distinct hybrids.  Epimediums are quite the promiscuous bunch, with bees creating both garden hybrids and well as natural hybrids in the wild.  While most epimediums make great garden plants, there are a few that offer little for gardeners, and these will not be discussed here.  For the purpose of this article, we are grouping my descriptions based on the plant morphology...plant characteristics that are easily observable, especially flowers. 

Epimediums spread via a woody rhizome, located just below the soil surface.  Just like bamboos, there are fast spreaders (leptomorphs), and slow spreaders that appear to form a tight clump (pachymorphs).  In the garden and nursery, epimediums can be divided, which is best done after flowering has finished. 

One of the most important tricks we learned from Darrell Probst is to always leave two-thirds of the foliage on the newly divided plants to encourage them to form new roots.  The tight clumping pachymorphs will be the most challenging to divide, hence the higher price these usually demand.  If you decide to try dividing them, get a pair of bonsai scissors.  Roots on divisions should be cut back to 4-5" long. 

Epimediums can be grown from seed, but you'll need to have a keen eye since the seed usually mature about 45 days after pollination (Probst).  We tried for years to gather seed, which must be sown fresh, with no luck and now we just allow the seed to fall into a well prepared seed bed, where it will germinate the following spring.  If you're lucky enough to gather the seed, they will require 60 days below 40 degrees F for germination.  We have been able to flower about 10% of one year old seedlings with the rest flowering the second year.  Since most epimediums are self-sterile, a lot of your offspring will be hybrids, creating a myriad of possibilities where many different species are grown nearby.

In gardening circles, epimediums are known as great plants for dry shade, but in the wild, most grow in very moist soils, with many being found near woodland waterfalls.  While epimediums will indeed grow in dry shade, they fare much better in part sun to light shade with a rich, organic, moisture-retentive soil.  As with all plants, stay away from salt-based fertilizers which can burn epimediums when used in excess.

Plants such as Epimedium x rubrum, Epimedium x warleyense, Epimedium x perralchicum, Epimedium pinnatum ssp. colchicum, and Epimedium x versicolor seem to be particularly durable in very dry sites. Most epimediums are native to alkaline soils, so we recommend a soil with a pH between 6.2 and 6.5 that allows us to grow all species well.  According to Dan Hinkley (Pacific Horticulture, 1997), the cultivars of Epimedium grandiflorum do not fare well in alkaline soils.

Most epimediums are spring flowering, with a few species such as Epimedium rhizomatosum and Epimedium davidii continuing sporadically through the summer.  We have categorized them into flowering times in the chart (Chart #1) below with some beginning as early as early March (NC- Zone 7b) and other not starting before late April. In areas subject to late spring frosts, the flowering spikes of many of the early flowering epimediums will need to be protected if temperatures drop below the mid-20s F.

Some epimediums have evergreen foliage, while others are completely deciduous.  As a rule, the deciduous species are more winter hardy than those that retain their foliage. When planting them in the garden, keep in mind that just because the foliage is evergreen doesn't mean it will look great throughout the winter.  For us, severely cold winters can damage evergreen foliage that in some mild years may look fine. Most gardeners trim any remaining damaged foliage in mid-late February, before the new flower spikes begin to emerge. 

While many epimediums are grown primarily for their flowers, several of the newer species and hybrids are worth growing for their lovely foliage.  Epimedium wushanense has superb mahonia-like leaves, while Epimedium acuminatum and Epimedium x omeiense are a couple of species with  wonderful leaf mottling.  Some selections of Epimedium x youngianum emerge purple or with a red border, as does Epimedium grandiflorum v. higoense. The leaves of Epimedium x versicolor are a kaleidoscope of colors as they emerge.

Below, we have categorized species by their plant form and flower types in order to help you select the best plants for your site.

Small species with small/medium sized flowers

If you're looking for small and dainty in the epimedium world, the deciduous Japanese Epimedium diphyllum (Zone 5-8) is for you. This cute garden plant has been in cultivation since the mid 1800s and ranges in flower color from light pink to white. The fading flowers are topped by a second flush of spring foliage. We consider Epimedium diphyllum to be a clumping species, but one which can make a 2' wide, easily dividable clump in 7 years.  Epimedium diphyllum and the evergreen Epimedium sempervirens have naturally hybridized to produce Epimedium x setosum, which is intermediate between both parents.

Mid-sized species and hybrid groups

Next are the most familiar group of epimediums...mid-sized plants that represent what most folks typically think of as epimediums.  Plants in this group average around 18" tall x 18" wide and are composed of several species and hybrid groups. From smallest to largest, they include Epimedium sempervirens, Epimedium x youngianum (Epimedium diphyllum x Epimedium grandiflorum), Epimedium grandiflorum, Epimedium koreanum, and a series of interspecific hybrids.  

Epimedium sempervirens (Zone 5-8) is a similar Japanese species to Epimedium diphyllum, except for having evergreen (from Zone 7 south) foliage, larger flowers and about 1/3 larger plant size.  Epimedium sempervirens produces flower stalks reaching 12-15" tall with 6-10 flowers each, also in colors ranging from white to lavender. Epimedium sempervirens is usually a tight clumping species, although some forms can spread a bit.  Another trait of Epimedium sempervirens is the new leaves often emerge with a lovely red flush. The major drawback to Epimedium sempervirens is the tendency of the second spring flush of foliage to obscure the flowers.

Epimedium x youngianum represents a large group of hybrids between Epimedium diphyllum and Epimedium grandiflorum.  A few forms are tardily deciduous, indicating that some hybrids attributed to this group may not belong here. Some clones of Epimedium x youngianum also have a second flush of foliage that obscures the flowers, but the problem isn't nearly as prevalent as in Epimedium sempervirens or Epimedium diphyllum.  As expected, Epimedium x youngianum is usually intermediate between the spreading clumps of Epimedium diphyllum and the tight clumps of Epimedium grandiflorum. 

Epimedium grandiflorum (Zone 4-8) is a winter deciduous Japanese species that represents the majority of the epimedium cultivars in commercial trade.  Like Epimedium sempervirens, most forms are tight clumpers, although a few may have longer rhizomes.  Many of the earlier selections of Epimedium grandiflorum have large flowers produced among or just slightly atop the foliage, usually obscured by the second spring flush.

Epimedium koreanum (Zone 3-7) was long considered a subspecies of Epimedium grandiflorum, but was finally split out as a species on it's own.  As the name indicates, it is found in Korea and northern Japan. While most Epimedium grandiflorum outside of Northern Japan where Epimedium grandiflorum var. flavescens resides, Epimedium grandiflorum has flowers of white to purple, while Epimedium koreanum has yellow flowers.  Also, the deciduous Epimedium koreanum spreads 6-12" per year via rhizomes compared to the typically clumping Epimedium grandiflorum.   

Epimedium x rubrum (Zone 4-8) is a name used for a group of semi-evergreen hybrids between E. alpinum and probably E. sempervirens (Probst - Garden Vision catalog 1997).  Epimedium x rubrum is most prized for its leaves, which emerge with a stunning reddish margin. The short spikes of pinkish red flowers can be obscured if the old foliage is not removed before flowering.   

Epimedium x versicolor (Zone 5-8) is the name for a group of hybrids between the deciduous Japanese Epimedium grandiflorum and the European native evergreen Epimedium pinnatum first raised in the Ghent, Belgium Botanic Garden in the mid 1800s. These hybrids are known for their stunning new foliage, which is chocolate, highlighted by green veins. From Zone 7 south, the foliage remains evergreen, but becomes deciduous as you head further north.  

Species with short flower spikes and large spider-type flowers

The next group are evergreen epimediums that have large flowers in pink to white, but are borne on short flower stalks.  Epimedium brachyrrhizum, first described from China in 1997 is similar to another species, Epimedium leptorrhizum (Zone 5-8) that has been known since 1938.  Both have spreading rhizomes with Epimedium brachyrrhizum possessing a thicker rhizome, spreading considerably slower.  For us Epimedium leptorrhizum never exceeds 6" in height, while Epimedium brachyrrhizum typically reaches 1' tall.  Both evergreen species are topped in early spring with very short flower spikes of 8-12 flowers ranging from pink to lavender, and occasionally white.

The foliage of Epimedium brachyrrhizum turns a nice shade of lavender in the winter.  Epimedium ogisui(1993) (Zone 6-9) is a similar spreading evergreen species with near horizontal spikes of large white flowers. The Chinese Epimedium epsteinii (Zone 5b-8), also named in 1997,  is a similar evergreen species with short, but spreading rhizomes and short flowers spikes, sporting up to 12 large bicolored inflorescences of purple cups and spurs, backed by a white outer sepal. Plants in this group make superb groundcovers, often with attractive red mottled foliage.       

Species with long flower spikes and large spider-type flowers (pink or purple)

Some of the most showy epimediums are those with large flowers on long spikes.  The evergreen Epimedium acuminatum (Zone 5-8) from limestone cliffs in the Southern Chinese provinces of Yunnan and Sichuan leads this list along with its hybrid, Epimedium x omeiense (acuminatum x fangii).   Epimedium x omeiense is fairly new to cultivation, first flowering in cultivation in 1982 (W. Stearn 2002).  In our studies, the primary easily visible difference is that Epimedium acuminatum has smaller, narrower leaves and is shorter in stature, 12" tall for Epimedium acuminatum, compared to 24" tall for Epimedium x omeiense.  Epimedium acuminatum flowers with 18" long arching spikes, each adorned with up to 50 large flowers composed of long dark purple spurs, highlighted by pale lavender inner sepals. The flowers are so large, the spikes can become quite heavy, so much that their tips nearly touch the ground.  For this reason, we recommend both Epimedium acuminatum and Epimedium x omeiense be planted atop a berm, so the flowers can be better enjoyed.  Both Epimedium acuminatum and Epimedium x omeiense are prized for their long-pointed and wonderfully mahogany mottled leaves. Compared to the tight clumping species, this is a reasonably good spreading species.   

Species with yellow spider-type flowers

There are a number of evergreen Chinese species with large cream to yellow flowers including Epimedium davidii, Epimedium fangii, Epimedium flavum, Epimedium hunanense, Epimedium franchetii, Epimedium lishihchenii, Epimedium rhizomatosum, Epimedium membranaceum, Epimedium chlorandrum, and Epimedium wushanense. 

Although first discovered on limestone cliffs in China around 1869, the garden worthy Epimedium davidii (Zone 5-8) wasn't introduced to cultivation until 1985. There are both tight clumping and slowly spreading forms of Epimedium davidii, both of which hold their spikes of up to 2 dozen curved yellow-spurred flowers above the small spiny green foliage for good visibility. Because new buds that form along the rhizomes and the leaf axils re-flower (Probst, American Nurseryman, 1998), it produces new flowers for us throughout the summer. Epimedium davidii is a superb garden plant deserving more widespread recognition, although it is not a species that performs well in dry locations. 

The Chinese Epimedium fangii (1995) (Zone 5-8), Epimedium flavum (1995) (Zone 5-8), and Epimedium hunanense (1931)(Zone 5b-8) are similar evergreen species with short flower stalks of bright yellow flowers. These are still little known in cultivation. Epimedium fangii is the fastest spreading of these species, followed by the vigorous Epimedium hunanense and then the dwarf Epimedium flavum. The flowers in this group are much small than the rest of the yellow spider group.

Epimedium franchetii (1996) (Zone 4-8) and the similar Epimedium lishihchenii (1997) (Zone 4-8) are slowly spreading evergreen species, also recently discovered in China..  Both of these species are similar in growth and form to Epimedium acuminatum and Epimedium x omeiense, but with up to 2 dozen large yellow flowers with recurved spurs, held horizontally on sturdy 2' long flower stalks.  Both species can produce foliage that emerges with an attractive bronze hue.  Although some folks argue that these represent a single species, we find that all of our clones of Epimedium lishihchenii have much larger foliage than Epimedium franchetii. 

Epimedium chlorandrum (1997) (Zone 5-8) is a similar slowly-spreading species native to Sichuan and also resembles Epimedium acuminatum, but the flowers are creamy yellow on 2' long arching spikes.

Another group of yellow spider-flowered epimediums include Epimedium rhizomatosum, Epimedium membranaceum, and Epimedium ilicifolium.  For us the Chinese Epimedium rhizomatosum (Zone 5-8) flowers longer than any other species, often reblooming throughout the summer.  As the name would indicate, Epimedium rhizomatosum, named in 1998, spreads via long rhizomes, as compared to the shorter rhizomes of the similar looking E. membranaceum (1922). Epimedium rhizomatosum is adorned with short 15" long flower stems of large-spurred yellow flowers. Epimedium membranaceum (Zone 5-8) is a similar species with up to 30 large-spurred yellow flowers on 2' long stems.  Epimedium membranaceum is a superb garden specimen that starts flowering just as Epimedium franchetii ends and continues all summer, thereby extended the flowering season.  The third and smallest of the group is Epimedium ilicifolium, a smaller growing (1' tall x 2' wide in 3 years) plant, composed of narrow, spiny green leaves.  Despite its small stature, Epimedium ilicifolium is one of the most floriferous of the group with light yellow flowers that are tightly packed along the flower spike as compared to the wide spacing of Epimedium rhizomatosum and Epimedium membranaceum.

As best we can determine, the slowly spreading Epimedium wushanense (Zone 5-8), although named in 1975,  wasn't sold before 2000. The long, spiny evergreen leaves (nicely mottled in some clones) up to 8" long come through the winter in great shape (NC), and serve as a nice background for the spikes of up to 100 long-spurred creamy-yellow flowers.  The entire flowering spike can reach nearly 3' in height. The flowers are bunched closely together and held just above horizontal on a very sturdy spike.

Species with small yellow bell-shaped spurless flowers

For something a little more dainty, there are yellow-flowered species without the long spurs of the group above.  Epimedium platypetalum (1922) (Zone 5-7) is a cute semi-evergreen Chinese species with spreading rhizomes and small yellow spurless bell-shaped flowers along 1' tall flowering stems.  Two other little known, but similar Chinese species with compact rhizomes are Epimedium ecalcaratum (1991) (Zone 5-7) and the clump-forming evergreen Epimedium campanulatum (1996) (Zone 4-7a), topped in spring with 2' flower stalks of small yellow bells.

Species with tiny white flowers

You'll never hear this next group decried as showy, but we would not be without these for their understated charm. The clumping, evergreen Epimedium sagittatum (1877) (Zone 5-8) is one of many Chinese species with tiny flowers, but the feature to recommend is the attractive cinnamon colored leaves as it emerges. Epimedium myrianthum (1998) (Zone 5-8) is  similar to Epimedium sagittatum, except the former usually has red tinted foliage, while the latter is often mottled and Epimedium myrianthum has a much larger number (up to 150) of tiny flowers. Epimedium pubescens (1877) (Zone 6-8) is a similar evergreen species with slightly larger flowers. Unlike the previous two, Epimedium pubescens comes in both a clumping and a creeping form. Epimedium stellulatum is relatively new, being introduced to cultivation in 1983 and only named in 1993. Epimedium stellulatum (Zone 5-8) is similar to the above three species, but with even larger flowers on a 20" tall stalk that gives it considerably garden value.  Other species in this group, which are still relatively rare include the Chinese Epimedium truncatum (1990) (Zone 5-8), and Epimedium baieali-guizhouense (1993) (Zone 5-8), each with tiny white flowers.

Species with Dodecatheon-like flowers

Several other favorites that don't resemble any of the aforementioned species are the clumping evergreen species Epimedium fargesii (1894)(Zone 5-8), Epimedium dewuense (2003) and the slowly spreading evergreen Epimedium dolichostemon (1988)(Zone 5-8).  In flower, these more closely resembles a dodecatheon (shooting star).  We find Epimedium fargesii to be of the most elegant, understated of all the fairy wings...unfortunately, the lack of commercial demand will probably keep it rare.  Epimedium dolichostemon which has wider spurs is also prized for its wonderfully mottled foliage. Epimedium dewuense is the smallest of the three with flowers that resemble a small Epimedium fargesii.

Other Species and Hybrid Groups

Other than the previously mentioned species and groups, there are a couple of others which are fairly widespread in commercial production. 

The European Epimedium pinnatum ssp. colchicum (1903) (Zone 5-8) is a lovely evergreen species.  Epimedium x warleyense is a hybrid of Epimedium alpinum and Epimedium pinnatum ssp. colchicum. This is one of the few true orange-flowered epimediums.   

Epimedium perralderianum (1862) (Zone 5-8) is the only species native to Africa...Algeria, in fact. The 1' tall stalk, held above the foliage is adorned with up to two dozen large bright yellow flowers. A similar looking hybrid to the parent derived from crossing Epimedium perralderianum with the closely related Epimedium pinnatum ssp. colchicum is Epimedium x perralchicum. This cross has long spreading rhizomes like its parents. 

Below is a list of epimedium hybrid group names...some already published, and others published here for the first time

Chart 1 - Epimedium Relative Flowering Times

*Flowering times are average in Zone 7b Raleigh, NC (average winter temperatures -15 degrees C (5F) and will be later in colder climates and earlier in others.

Early March - Mid March

• pubescens - ends late April

Mid March - Late March

• brachyrrhizum - ends mid-April
• chlorandrum - ends late April
• epsteinii - ends mid- April
• fargesii - ends mid-April
• franchetii - ends mid-April
• sagittatum - ends early April
• sempervirens - ends mid April
• stellulatum - ends early May
• truncatum - ends early May 

Late March - Early April

• acuminatum - ends early May
• davidii - ends May-July
• dolichostemon - ends mid April
• grandiflorum - ends mid April
• leptorrhizum - ends mid- April
• lishihchenii - ends mid-April
• myrianthum - ends mid-April
• ogisui - ends late April
• pauciflorum - ends mid-April
• rhizomatosum - ends mid-May
• x rubrum - ends mid-April
• x setosum - ends mid April
• x versicolor - ends mid April
• x youngianum - ends mid April

 Early April - Mid April

• baieali-guizhouense - ends late May
• brevicornu - ends mid-May
• x cantabrigiense - ends early May
• diphyllum - ends late May
• grandiflorum v. higoense
• hunanense - ends late April
• ilicifolium - ends late April
• x omeiense - ends early May
• x perralchicum - ends late April
• pubigerum - ends late April
• x sasakii - ends late April
• wushanense - ends late April 

Mid April - Early May

• dewuense - ends early May
• membranaceum - ends August
• platypetalum - ends early May 
• shuichengense - ends mid-May  

We hope you find this group as enjoyable as we do and hope your interest in epimediums has been "spurred" to new heights.  Again, a final thanks to Darrell Probst, without whom this would not have been possible and without whom many of these great epimediums would never have made it into commerce.