How to Understand Your Yard's Sunlight So You Know What to Plant Where
Full sun, part shade, full shade; it can get confusing! This simple guide will help you gauge sunlight levels throughout your landscape so you can pick the best plants to thrive in each unique area.
Sunlight, along with water and soil, is a key component for healthy foliage, flowers, and fruit. Of course, the amount of light your yard gets will change throughout the day as shadows from building and taller plants move with the sun. Most plants will thrive in at least six hours of direct sunlight, which is often called full sun for gardening purposes. But many plants will unfurl fabulous foliage and beautiful blooms in less light than that, so you can still create a lush and colorful garden in all but the shadiest conditions. Here's what you need to know to make the most of every kind of light level in your landscape.
Study Your Yard's Sunlight
Get started by recording how much sunlight your yard receives over time. Assess light patterns every hour or two throughout the course of a day, noting where shadows fall and for how long. Keep in mind that in spring, bare-branched trees may give the illusion of sunny spots beneath, but once they leaf out, they often create heavy shade during summer and into fall. Buildings and walls also cast shadows; consider those structures as you plot the sun's path over your patch of earth.
Use marking flags or stakes to indicate light and shadow in your yard. Or you can create a light map on paper. Start with a few sheets of tracing paper, sketching a copy of your yard's outline on each page. About two hours after sunrise, observe where light and shade fall and mark them on the tracing paper, noting the time. Repeat the process through the day, each time using a different sheet of paper. Stop recording about an hour before dusk. Use a pencil to mark shady sections of the yard on each page. Label sun and shade pockets to indicate whether they reflect morning or afternoon conditions. Layer the pages together, and you'll get an accurate picture of how much light your yard receives. Create a composite drawing to use as a one-page light map.
Understanding Sun and Shade Areas
Parts of the landscape that receive sunlight nearly all day are straightforward to work with when it comes to designing gardens and choosing plants. You can count on the intensity of sunlight to vary slightly based on time of day, with morning light offering softer, gentler rays and afternoon sun blazing with sizzling rays.
Shade is a little more complicated. There's the deep shade you find on the north side of a house; alongside a stone wall or privacy fence; or beneath a 70-year-old beech tree, where the sun only peeps from winter through early spring. Pair these deep shade locations with plants that don't require very direct sunlight to thrive.
Dappled shade dances beneath honeylocust trees, where small leaves filter sunlight to cast a shifting glow. Deciduous trees, like maples and ashes, offer seasonal shade. Spring sunlight under leafless boughs provides the perfect place for ephemeral plants, such as bleeding heart or naturalizing spring bulbs, which produce an early-season flower show and then quietly disappear as tree canopies fill in and shade deepens. As the sun takes an overhead route, shade patterns shift and shorten in summer under deciduous trees and then lengthen as summer moves into fall. These seasonal light patterns are helpful to know as you choose and situate plants for your garden.
Test Garden Tip: In a woodland setting, tall trees often cast light shade, punctuated by shafts of sunlight. Count on reliable shade performers such as astilbe to brighten shady gardens with colorful blossom spires. Plant a mix of astilbe varieties that bloom at different points in the season to create a longlasting flower show. Companions for astilbe include golden hakonegrass, goatsbeard, hostas, and several types of ferns.
A plant's light requirements shift throughout the United States. In the South, sun-loving plants might need shade during the hottest part of the day, while in the Pacific Northwest, cloud cover can prevent sun-lovers from flourishing. Where cool, wet summers prevail, plants that nominally prefer partial shade can thrive in sunnier conditions.
Plants and Light Requirements
Most plants have preferred light conditions for top-notch performance, which are often described as full sun, part sun, part shade, or full shade. Not sure what these terms mean? You're not alone. Here's how to decipher the light code.
Full sun: Plants require at least six hours each day when the sun shines directly on them.
Part sun/part shade: These terms usually mean the same thing; that plants should receive three to six hours of sun per day, preferably in morning or evening, not during the hottest parts of the day. The rest of the time, the plants can be completely shaded or in dappled shade.
Full shade: Plants need fewer than three hours of direct sun per day. This could describe the conditions found on the north side of a structure or under a shade tree where sunlight briefly penetrates the canopy at some point during the day.
You can make some shade do a disappearing act. If you have a tree with branches that cast dense shade, lighten the scenery below by removing lower limbs. This process, called limbing up, effectively lifts a canopy, permitting sunlight to penetrate the leafy shade more. During late summer and fall, sunlight can slant beneath limbed-up trees to lighten deep shade. Selectively thinning can increase light to the ground below. Consider replacing solid fences with vine-covered lattice to increase light.
Rules Are Flexible
Once you know your garden site's sun and shade characteristics, start picking out plants. And keep in mind that if you place a plant where it gets too much or too little light, you won't necessarily kill it. You'll likely experience fewer flowers, shorter life span, less color, or gangly stems. So if an annual or perennial isn't thriving in a given light location, grab your shovel and transplant it to another spot. Plants are tough; they usually can handle moving from place to place.