Sun vs. Shade - How Much Light?
A big part of matching the right plant to the right place is figuring out how much light your planting area gets. Light is a dynamic thing through the day and through the seasons so you'll want to make observations at different times of the day and, if possible, at different times of the growing season. If your planting location gets full sun all day long, your light analysis is pretty straight forward. If that's not the case, check your site at one hour intervals from 9:00 AM until 6:00 PM and note how much sun the area receives and at what time of day. Sun at 3:00 in the afternoon is much hotter and intense than sun at 9:00 in the morning.
Use the following designations to categorize what you observe:
A sunny site receives six or more hours of direct sunlight between 10:00 am and 4:00 pm. See our our complete listing of Sun Perennials
Partial Shade (or Part Sun)
In part shade, plants should receive less than 6 hours of sun a day. This is an area that gets sun part of the day and shade part of the day. A wall, building or distant trees might produce this type of shade. Gardens on the east side of a building usually get morning light and afternoon shade while gardens on the west get morning shade then intense hot sun in the afternoon. Areas where open tree branches allow sunlight to flicker across the ground and areas that get patches of sun intermittently through the day also qualify for partial shade .Good candidates for part shade include Actaea, Ajuga, Aruncus, most ferns, Brunnera, Buxus, Carex, Hakonechloa, Helleborus, Heuchera, Heucherella , Hosta, Hydrangea, Pulmonaria, Tiarella.
In full shade, plants generally receive less than 3 hours of sun a day. Many shade perennials will perform better with some sun.