What do all these lighting requirements mean?

How much light is enough? How much is too much, or not enough? These are the four primary categories that you need to remember.

Scenic view of a winding road through peaceful countryside fields with blue skies.

Full Sun

Not a hint of shade in sight. Seedlings might get a tiny bit of relief from tall prairie plants, but generally there is nowhere to hide. These plants get at minimum 6 hours to a full day’s worth of sun.
In larger habitats, these types of areas are often maintained with fire ecology to prevent pioneering tree species from germinating and gaining a foothold. This is also a common site on pastures and old abandoned farmland, where wild species have begun moving in. You can also find this on rocky bluffs or glades and in alpine habitats above the tree line. At home, this is in the middle of the lawn.

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Part Sun

You’ll find this in transition zones between open meadows and wooded areas, in forest clearings, clear cuts, areas with canopy die-back. They will get some direct sun (around 2 hours or more) during part of the day, but it will be less than 6 hours total.
This is common in orchards, abandoned unmanaged farmlands where tree species have begun moving in and are tall enough to begin casting shade. At home, you’d find this on the eastern or western portion of the house or any structures that cast shade part of the day.

A tranquil forest scene featuring a shaded path and an old wooden shed surrounded by lush greenery.

Light Shade

This is the lighting condition that is common a bit deeper into the transition area between an open meadow and forest, often filled with thickets where unmanaged. You will also find this where there is an opening in the canopy, either due to a roadcut, power lines, railways, areas with big boulders or cliffs, water features, and so on. Indirect light filters through the canopy.
At home, you’d find this wherever you have a few trees planted spaced far enough apart for them to grow full canopy spreads, but the canopies are open enough to allow a bit of sun to get through.

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Shade

So little light reaches the ground that you cannot see the sky, and you are amazed that anything can grow in a space that ranges between dark and midnight. These areas are filled with mosses, ferns and a smattering of sedges. In deciduous forests these areas are quite bright, more like part sun conditions, and there will likely be some populations of ephemerals. Once the trees leaf out, there is no more light hitting the forest floor. In evergreen coniferous forests, it’s dark pretty much year-round. Most ephemerals do not grow here, and new trees cannot germinate and grow.
At home, this is the northern side of shade-casting structures or on heavily wooded properties.

“light condition” to “light condition”

Lighting Ranges Indicate a Plant’s Range of Tolerance

The vast majority of plants are adaptable to a range of lighting conditions. Shade plants need to adapt the moment a tree dies and falls, suddenly allowing far more light to filter in. Meanwhile, sun plants need to adapt for pioneer species that take root and begin casting shade as they grow taller. After all, nature isn’t a static picture. A wild landscape is constantly changing through the years.

Knowing this, by learning in which habitats our native plants naturally occur, these ranges make more sense. We need to think of lighting requirements as they might exist over a span of a lifetime, not just throughout the day. Areas that receive full sun now would not necessarily get it throughout their lifespans. Areas cast in deep shade may suddenly find themselves cast in brighter light due to the death of mature trees, a forest fire, landslide, or other calamity.

One last point I need to make: plants require a lot of energy to produce flowers and fruit. Shade plants understandably produce far less of it than ones which grow in full sun. There are, of course, always exceptions to the rule. When siting a plant, you generally want to aim for the highest light tolerance. Any plants that prefer something in between, but can tolerate lighting in either direction are noted in that plant’s description. It is true that I have asters that grow and bloom in full shade, but moved to a sunnier location, they grow far more dense and bloom prolifically. In the shade they tend to grow sparse with a few blooms here and there. The more sun they get, the more energy they can devote to reproduction.

Sun to Part Sun

Prairie plants that will adapt to a few trees moving in that cast shade. As more trees fill in, their populations begin to die back.
If these plants were people, they would spend a significant amount of time tanning in the yard, adding oil for good measure. In the winter they would continue visiting tanning beds just to get enough sun, and likely would have daylight-temperature bulbs throughout their homes.

Sun to Light Shade

Marginal species (existing between open meadows and forest edges) that can grow anywhere within that margin. Once the mid-succession species take over pioneer, their populations dwindle. One of the species I find well adapted to this shift is Liatris spicata. While they really prefer to grow in full sun, where they’re far more robust and taller, I’ve found them reseeding in the shade of a maple tree. They will still bloom and produce seed, but they rarely reach more than 18″ tall at most. I particularly like the more shade-adapted Liatris growing in my yard.

Sun to Shade

These can handle it all, and exist in all spaces, from sunny lawns to dense forests. Nothing can bring these down. They’re the most chill of the plant kingdom, happy to be growing wherever they find themselves, and bounce back relatively quickly should the situation take a 180. Plants like blue eyed grass or spring beauties are quite adaptable, and you can find them growing just about anywhere. They’re happy to be alive, no matter where they put down their roots.

Part Sun to Light Shade

These species grow closer to the forest in a transitional area. They may also be found along streambanks, floodplains, oak savannas. The total opposite of the chill sun to shade crowd, these are the goldilocks plants. Not too much light, but also not too little – it needs to be just right. One example would be spring-blooming ephemerals, which begin going dormant as the trees begin leafing out.

Part Sun to Shade

Forest plants that are adapted to disturbance. They normally may grow in shady conditions, but won’t burn if a tree falls, suddenly casting them into more light than they’re used to. Like the aforementioned aster growing in my woods, they take advantage of this situation to replenish the seed bank with their progeny. These may also be the later-blooming spring ephemerals, such as ramps. Allium tricoccum get their photosynthesizing done while the trees are bare, saving their blooms for early summer once it’s warm enough for a greater presence of pollinators, though now in full shade.

Light Shade to Shade

The red-headed Scots-Irish children in the plant kingdom, where any amount of sun gives them sunburn. SPF100 only, please, but really, staying out of the sun is best. They aren’t completely useless in the landscape, because they can quite literally handle growing “where the sun don’t shine.” You may even find some of these in evergreen, coniferous forests.

What are the lighting conditions on your property?

While there are many gadgets designed to calculate this for you, they can only do this in one area at a time. If you have a large property, that is quite an investment to make up front, in addition to not teaching you how to adjust for any shrubs or trees you may choose to add to the property. With experience, you learn to read the landscape without needing to map the sun. If you’re just getting started, try this guide to sun mapping provided by Robert Pavlis.

GardenMyths guide to sun mapping

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Now that you understand what lighting conditions mean…

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