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Epimedium ‘Amber Queen’ is one of the new generation of floriferous hybrids This increased dramatically to 54 in the updated edition (Stearn 2002) that he completed just before his death in 2001. Even as late as the early 1990s only a handful of the known species were in cultivation. Recently introduced species 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. His discoveries include E. campanul atum, E. chlorand­ rum, E. dolichostemon, E. fangii, E. flavum, E. franchetii, E. ilicifol ium, E. latisepalum, E. ogisui, E. mikinorii, E. rhizomatosum and previously named species that were not in culti vation such as E. brevicornu, E. ecalcarat um, E. fargesii, E. lish ihchenii, E. pauciflorum and E. platypetalum. Probst’s introduct ions include An stated unless Nursery, Plant Delights All photographs: E. brachyrrhizum, E. dewuense, E. epsteinii, E. myria nthum and the previously described E. sutchuenense. overview Many yet to be published species from his work are in the pipeline. As of 2008, my collection at Plant Delights Nursery in North Carolina of Epimedium consists of 49 of the currently named 54 species, along with most of the distinct hybrids. Epimediums To n y Av e n T t w a s o v e r 40 y e a r s into are promiscuous, with bees creating my gardening life before I got garden hybrids and natural hybrids in surveys the cultivated involved with epimediums, the wild. While most epimediums species, highlights Ipartly because I found the conflicting make great garden plants, there are a information about them confusing. few that offer little for gardeners, some of the recent It was only with the assistance of and these will not be discussed here. cultivars, and Epimedium guru, Darrell Probst, that I was finally able to embrace them. Propagation describes his In the late Prof. William Stearn’s Epimediums spread via a woody favourites first Epimedium monograph (Stearn rhizome located just below the soil 1938) only 21 species were known. surface. As with bamboos there are 10 March 2010 PlantsmanThe fast spreaders (leptomorphs) and spring frosts the flower spikes of slow spreaders that appear to form a early­flowering ones will need tight clump (pachymorphs). Division protection below ­4°C. is best done after flowering. The Some epimediums have evergreen pachymorphs are the most challeng­ foliage while others are completely ing to divide, hence the higher price deciduous. As a rule, the deciduous they usually demand. If you try to species are hardier than those that divide them use a pair of bonsai retain their foliage. When planting scissors. Roots on divisions should them in the garden, keep in mind be cut back to about 10cm long. One that just because the foliage is of the most important tricks I evergreen does not mean it will look learned from Probst is to always great throughout the winter. Where leave two­thirds of the foliage on I am based, severely cold winters can newly divided plants to encourage damage evergreen foliage that in some them to form new roots. mild years may look fine. Most Epimediums can be grown from gardeners trim any remaining seed, but you will need to have a keen damaged foliage in mid to late eye as the seed is small and the February, before the new flower capsules can split without warning. Epimedium sagittatum ‘Warlord’ (above) and spikes begin to emerge. While many Seed is usually mature about 45 days Epimedium ‘Yokihi’ (below) are two new selections epimediums are grown primarily for after pollination (Probst, pers. comm.). their flowers, several of the newer I tried for years to gather seed, which colchicum, E. x rubrum, E. x warleyense species and hybrids are worth growing must be sown fresh, with no luck, and E. x versicolor seem to be partic­ for their lovely foliage. Epimedium and now I just allow it to fall into a ularly durable in very dry sites. Most wushanense has superb mahonia­like well­prepared seed bed where it will epimediums are native to alkaline leaves, while E. acuminatum and germinate the following spring. If soils, with the exception of a few E. x omeiense have wonderful leaf you are lucky enough to collect seed Japanese ones such as E. grandiflorum. mottling. Some selections of it will require 60 days below 4°C I recommend a soil with a pH of 6.2 E. x youngianum emerge purple or with before germinating. At Plant Delights to 6.5 – although on the acid side, a red border, as does E. grandiflorum Nursery we have been able to flower this allows us to grow most species var. higoense, and the leaves of about 10% of one­year­old seedlings well. According to Dan Hinkley E. x versicolor are a kaleidoscope with the rest flowering in the second (1997), the cultivars of E. grandiflorum of colours as they emerge. year. Since most epimediums are do not fare well in alkaline soils. Here I have categorised species by self­sterile, offspring tend to be Most epimediums are spring their size and flower type in order to hybrids if you grow more than one flowering, with a few species such as help you select the best plants for species, creating many possibilities. E. rhizomatosum and E. davidii your site. I have also given US hardi­ continuing sporadically through the ness zone ratings; most of the UK is Cultivation summer. In areas subject to late in Zone 8. Many of the cultivars are In gardening circles, epimediums are only available in the US at present known as great plants for dry shade. but hopefully enterprising nurseries However, in the wild most grow in will distribute them further. very moist soils, with many being found near woodland waterfalls. Small species with small or While epimediums will indeed grow medium flowers in dry shade, they fare much better If you are looking for small and in part sun to light shade with a rich, dainty in the Epimedium world, the organic, moisture­retentive soil. As deciduous Japanese E. diphyllum with all plants, avoid using salt­based (Zone 5–8) is for you. This dainty fertilisers which can burn epimediums species has been in cultivation since when used in excess. Hybrids such as the mid 1800s and ranges in flower E. x perralchicum, E. pinnatum subsp. colour from pale pink to white. It ➤ March 2010 11 E. sempervirens ‘Violet Queen’ E. x youngianum ‘Tamabotan’ E. grandiflorum ‘Purple Prince’ is represented in cultivation primarily emerge with a lovely red flush. ‘Tamabotan’ (purple foliage, pale by three cultivars, ‘Nanum’ (white Cultivars include ‘Candy Hearts’ lavender flowers), ‘White Cloud’ flowers), ‘Roseum’ (pink flowers) and (red­edged leaves, pale lavender (small clump, white flowers) and ‘Vanilla Ripple’ (syn. ‘Variegatum’) flowers), ‘Cherry Hearts’ (red­edged ‘White Star’ (white flowers). (speckled leaves).The 20cm tall leaves, white flowers), ‘Mars’ (red­ At the nursery we find each of flower spikes bear two to six flowers purple flowers), ‘Okuda’s White’ the above cultivars to be dramatic each, certainly nothing to match the (white flowers) and ‘Violet Queen’ improvements over E. x youngianum show ier species, and the fading (red­flushed foliage, pale lavender ‘Niveum’ and E. x youngianum flowers are topped by a second flush flowers). The major drawback to ‘Roseum’. Some have a second flush of spring foliage. I regard E. diphyllum E. sempervirens is the tendency of the of foliage that obscures the flowers, as a clumping species, but one which second spring flush of foliage to but the problem is not nearly as can make a 60cm wide, easily obscure the flowers. prevalent as in E. sempervirens or dividable clump in seven years. Epimedium x youngianum represents E. diphyllum. As expected, E. x Evergreen E. sempervirens has a large group of hybrids between youngianum is usually intermediate crossed with E. diphyllum in the wild E. diphyllum and E. grandiflorum. A in habit between the spreading to produce E. x setosum, which is few cultivars are tardily deciduous, clumps of E. diphyllum and the intermediate between the parents. indicating that they may not belong tight clumps of E. grandiflorum. here. Cultivars attributed to this Epimedium grandiflorum (Zone Mid-sized species and hybrids hybrid include ‘Baby Doll Pink’ (small 4–8) is a winter deciduous Japanese This group of plants, typically 45cm clump, small pale pink flowers), ‘Be species that includes the majority of tall and 45cm wide, is the most My Valentine’ (very floriferous, dark Epimedium cultivars in the trade. familiar to gardeners. Darrell Probst pink sepals with a white cup), ‘Beni­ Like E. sempervirens, most cultivars has interesting theories on the origin kujaku’ (pale lavender flowers), are tight clumpers, although a few of this and related groups that he will ‘Capella’ (pink sepals, white spurs), may have longer rhizomes. hopefully publish one day. ‘Fairy Dust’ (small pale pink flowers), Cultivars of E. grandiflorum include Epimedium sempervirens (Zone 5–8) ‘Grape Fizz’ (small pale lavender ‘Bandit’ (dwarf plant, red­edged from Japan is similar to E. diphyllum, flowers), ‘Liliputian’ (very dwarf, leaves, white flowers), ‘Benedict’s except for being about one­third attractive white flowers), ‘Milk Choc­ Violet’ (lavender flowers), ‘Bronze larger with evergreen (from Zone 7 olate’ (chocolate mottled leaves, Maiden’ (chocolate foliage, pale lav­ south) foliage and larger flowers. The white flowers), ‘Milky Way’ (white ender flowers), ‘Cranberry Sparkle’ flower stems reaching 30–40cm tall flowers), ‘Murasaki­shikibu’ (purple (chocolate new leaves, cranberry red with six to ten flowers each, also in sepals, white spurs), ‘Pink Star’ (pale flowers), ‘Dark Beauty’ (chocolate colours ranging from white to pink, nearly white flowers), ‘Purple leaves, purple outer sepals, white cup lavender.

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