Proper sun exposure is integral to the survival of plants. Too little, and your plants become weak, thin, and sad-looking. Too much and they spend two-thirds of the day drooping ! This isn’t really a new concept – so why is it so difficult to figure out which plants belong in which parts of your garden?

How Sunny is Full Sun?

Part of the difficulty is that there are some overlapping (or just downright confusing) terms out there that describe the light requirements of plants. After all, what’s the difference between Part Sun and Part Shade? How many hours of light does a Full Sun location actually get? There’s no sense looking for plants tolerant of ‘dappled light’ if you have no idea what that actually means. Below, we’ve listed some of the terms you might see while researching plant choices, either online or in-store. Note that these are our definitions, and though we’re confident in our wording, there’s bound to be some out there who disagree.

Direct Light: A plant is exposed to direct light when the sun is shining directly on it.

Indirect/Incidental Light: A plant is exposed to indirect light when the sun isn’t shining directly on it but it still receives light; it can be reflected off of nearby surfaces or perhaps the location is open to the sky.

Dappled Light: This one is tricky. Trees such as honey-locusts or birches have very open canopies that let a high degree of light through them even when they’re in full leaf. These areas receive a combination of direct and indirect light, allowing for a surprisingly wide variety of plants to be grown nearby. Consequently, areas with dappled light are not dark enough for plants that prefer full shade.

Full Sun: Plants that require at least six hours of direct sun each day fall into this category.

Sun to Part Shade: Plants that prefer at least six hours of sun each day fall into this category. These plants will tolerate 4 – 6 hours of light, but they may lose some of their visual appeal (i.e. less blooms, and bright foliage may turn greenish).

Part Shade: Plants that prefer around four hours of direct sun each day or dappled light all day. These plants will likely struggle if planted in full sun or full shade.

Part to Full Shade: Plants that prefer around four hours of direct sun each day. These plants will tolerate less than four hours, but they may lose some of their visual appeal.

Full Shade: Plants that prefer a maximum of 3 hours of direct sun each day. It is important to clarify: low-light plants are not no-light plants. Unless you’re growing mushrooms, your plants will need some amount of light to survive. Basements, garages, or any place where physical barriers completely block the sun are not suitable for growing plants.

Sun to Shade: Plants that have no preference and can tolerate full sun, full shade, or anything in between.

Changing Seasons, Changing Conditions

Another part of the difficulty in picking plants suitable to your yard is that the light conditions change from season to season, and even from month to month. You could look out your window in February and assume that the north-west corner of your house only gets a few hours of sun a day. Come July, however, that spot will probably be subject to eight hours of blistering hot afternoon sun. Our latitude means that in the winter, the sun hangs in the south sky, while in the summer it tracks much further north.

It isn’t just the sun that changes, either. Nearby trees that are barren early in the spring will create additional shade once they leaf out. It’s important to try and picture what your yard will look like during all three seasons when deciding how much light your yard actually receives.

Furthermore, as your garden grows, lighting conditions will change from year to year. A tiny maple sapling may come to turn your entire backyard into a full shade location in fifteen years.

Now, you’re going to drive yourself crazy if you sit there trying to predict how your garden will look in fifteen years’ time. But it’s good to keep some of these thoughts in the back of your mind, to be addressed as time goes by.

Survive, or Thrive?

A final bit of confusion is that sometimes we mistakenly assume that plants will adapt to any location — perhaps your neighbour has a Lilac tree growing in shade. This is true, to a point — plants will do all sorts of miraculous things to adapt to difficult locations; in the shade they’ll produce more chlorophyll to compensate for lower light levels, and will grow taller than usual as they “reach” for sunnier areas.

In such situations, however, it’s important to distinguish between locations a plant will survive in and locations it will actually thrive in. The lilac growing in the shade won’t flower, and will likely suffer from recurring mildew and disease issues because it is growing poorly. Most of us will find growing a lilac in the shade difficult, and this plant will consume a lot of time and attention.

For this reason, we label our plants on the assumption that you want them to thrive. A Magic Carpet Spirea can probably survive in shady areas, but all of the things we’ve come to enjoy about it – its bright foliage, dense habit, and early summer flower clusters – will be absent in the shade. For that reason, our signage categorizes all of our Spirea as “Full Sun” plants.

Once you sort out lighting needs, the next step is to make sure you’re watering correctly. Check out our post on Watering Pitfalls to learn some quick and no-nonsense watering tips.