LIGHT AND SHADE TERMS IN GARDENING EXPLAINED

I always tend to get confused when I have my eye on a certain plant and the label tells me it needs a certain condition, partial shade, plant hardiness zone, or whatever, and I am left trying to work out if my garden's growing conditions fit the bill.  After all, for example, my kitchen window faces more or less eastward.  In winter, if we are lucky enough to get any sun at all, it only gets a few hours until, perhaps, only 9 or 10 a.m., then it is in shade. At that time of year, there are very few plants there to worry about.  However, in spring and summer it's a different story when my garden comes alive. most are dormant. That same place can get full blazing sun until mid-day when the sun heads over to the other side of my home.  So, does that count as partial shade?  Apparently it does.

East facing wall with morning summer sun and plants that get partial shade

FIFTY SHADES OF SHADE AND LIGHT



Light shade is an area where there is nothing above but sky, nothing overhanging like an awning, or a dense canopy created by trees, but that an object (like a high fence, wall, or hedge, blocks direct light from the sun.   



Partial shade is an area that receives two or three hours of sunlight in the early morning or late evening.  The reason for being specific about time of day is because the strength of sunlight increases at mid-day when the sun is overhead and, thus, nearer. 



Moderate shade is an area that receives reflected light (for example off a white wall, a shiny object - like a mirror) or diffused light (light that is filtered through overhead trees, for example).



Deep Shade is an area that receives hardly any light at all, as under a dense canopy of overhanging trees. 

Dappled Shade is diffused light that filters through to plants, sunlight through a canopy of trees, for example.





A more extensive explanation is available here at RHS Shade Gardening (external link)





Be aware though that all these rules are verging on guidelines. I mean, some plants can tolerate various conditions depending upon circumstance.  For example, Japanese Maples can tolerate a lot of sun as long as they are well watered (with good drainage) and their roots don't dry out.  When that happens, then the foliage suffers and shrivels.  They are actually better off in the ground than in containers where they can dry out more quickly.