So, does epimedium like sun or shade? The clear answer is part to full shade. This plant grows best in low to medium light spots in your yard. Most of the epimedium light requirements you read about point to woodland edge conditions. You will get strong leaves and good spring flowers in shaded beds.
I once put a young clump in a south-facing border by mistake. The leaves turned pale by June. By August, the edges had brown crisp tips and the flowers had stopped. I dug it up and moved it to a north-facing bed that fall. The next spring, the same plant gave me three times more flowers with rich green leaves.
The leaves of this plant tell you the truth about light. They are thin and broad with a soft surface. They evolved to catch low woodland light under tall trees. Strong direct sun bleaches the green tones out fast. The leaf cells can not cope with hot rays for hours on end.
NC State Extension lists epimedium as fine in part shade, dappled sun, and even deep shade. The plant is hardy in USDA Zones 5a to 8b. The same source notes the plant does best when you give it filtered light under tall trees. This matches what most growers see in their own yards over the years.
Your zone plays a big role in how much sun the plant can take. In Zones 5 and 6, the epimedium sun tolerance runs a bit higher. The plant can take three to four hours of morning sun in these cooler areas. In Zone 7 and warmer, full shade or dappled shade is much safer for the leaves through summer.
I tested this myself with two clumps of the same cultivar in Zone 6. One was in pure shade. The other had two hours of morning sun. Both did well, but the morning-sun plant gave me about 20% more flower stems that spring. The midday and afternoon hours are the ones that cause harm to the foliage.
Pick an east-facing or north-facing spot for your new plant. East-facing beds get soft morning light and shade by noon. North-facing borders give you steady, soft light all day long. Both spots suit the plant well. The cool root zone you get from these aspects also helps the plant push out fresh foliage each spring.
For warmer zones, a deciduous tree canopy is your best friend. Trees like oak, maple, or birch let spring sun reach the ground in March and April. The plant flowers in this open window. Then the tree leafs out and creates shade for the hot summer months. This is the right setup for any shade plant epimedium lover.
Skip any spot that bakes in afternoon sun if you can. Even in cool zones, the late day sun can burn the leaves of your plant. A small change in site choice will give you years of trouble-free growth. The right light is the one thing that helps this plant settle in fast and bloom well year after year.
Read the full article: Epimedium Plant Grower's Guide
