by Barb Levisay
Walking through the garden center, labels let you know right off the bat whether each plant likes sun or shade. Those labels are critical in helping you choose the plants that will thrive in your garden environment. But the flip side—how much sun exposure do your flower and veg beds get—is trickier than you might think.
Until a few years ago, I thought I had a good handle on how much sun each of my flower beds got. After losing a couple of sun-loving shrubs in a bed I thought was full sun, I decided to put it to the test. Over the course of a week, I checked each hour of the day to see if the bed was in sun or shade. The results surprised me and inspired me to be more “data-driven.”
Is the amount of sun a bed gets really that important?
Yes, it is. When you invest your time and money planting a garden, whether flowers or vegetables, you want to get the best results possible. Each plant has light requirements, and it’s pretty easy to search and find out what those requirements are.
For vegetable gardens, full sun is a requirement. You’ll have some veg successes with less than 6 hours of full sun, but you’ll have a lot of disappointments as well. It’s a bit easier for the ornamentals. No matter what the exposure of your flower beds, there are great options out there. You can find foliage and flowers that suit the site and will fill your yard with color.
Plant tags or online descriptions will guide you on whether a plant needs sun, shade or something in between. Generally accepted guidelines are:
Full sun plants require 6+ hours of direct sunlight
Part sun plants require 3-6 hours of direct sunlight
Part shade plants prefer 3-6 hours without late day direct sunlight
Full shade plants want less than 3 hours of direct sunlight
So many shades of sun
Living in a region with hills and lots of trees means there are plenty of sun obstructions that cast shadows on our garden beds. Rarely do we get the luxury of a garden bed in the middle of the lawn with uninterrupted sun exposure. Your ornamental gardens were likely built to enhance the look of the house without regard to how much sun they get.
Of course, accurately gauging the amount of sun each of your beds gets is tricky because it’s constantly changing. Leaves come and go, trees and shrubs get bigger, the sun travels up and down the horizon through the year—the shadows and light on your beds are always on the move. But by understanding your sun exposure better, you can choose plants and place them in locations that most closely match their requirements.
The sun exposure of a single bed can vary greatly based on the shadows cast by trees and buildings.
This past winter, many of us lost trees and limbs that will drastically change sun exposure. At our house, the beautiful white oak that shaded our deck and protected the “shade bed” for 30+ years came down. That bed, which held hostas, hellebores, astilbes and bleeding hearts is now very much full sun. I have to find new spots for all the shade-loving plants and re-fill that bed with sun worshipers.
Sun-tracking tips
Since I learned so much from my first exercise, I’ve become a bit of a sun-tracking nerd. With a clear understanding of the amount of sun an area will receive, I know I’m giving my plants the best possible environment to flourish. My notes help me plan out bed design during the winter months, when it’s hard to remember where shadows fell when the leaves were on the trees and the sun was higher in the sky.
To make tracking easier, I’ve made a set of flags numbered 1 through 6. I set those flags out across the beds I want to track and log my observations. Old school, I use a pencil to fill in the table over the course of a week, checking whether my flags are in sun, shade or dappled whenever I think of it.
A simple table tracking sun exposure helps you choose the plants that will thrive in that location.
I get started sun-tracking in April or May when most trees are fully leafed out. Tracking again around the solstice and the fall equinox gives me a complete picture of the sun exposure across the growing season.
You certainly don’t need to be as nerdy as me about sun-tracking to get real benefits. Just being more aware and noting how much sun your beds are getting will give you more success in the garden. Your plants don’t ask for much, but they do want the right amount of sun to give you their very best.
If you have a question, send a note to me at barb.levisay@gmail.com .