Which side of a fence is exposure measured on?


I have a fence which faces southwest. The fence is a relatively open board construction, so the stems will definitely grow through toward the sun.

If I plant the rose on the shadier side (i.e. the northeast side) is light eposure
FULL SUN because the stems and leaves are in the sun,
SHADE (because the roots and base will have much less sun)



Thank you for your question.  As you have identified, the direction in which your yard faces affects the amount of sunlight your garden receives. In general, south-facing yards get the most sun, north-facing sites the least.

You have a southwest facing fence…so the “full sun” would typically be on the south west side, not the north east side of the fence.  In your garden, where the inside of your fence is facing north, the sun will always cast a shadow over the area immediately inside the fence. In the summer the shadow will be shorter and in the spring and autumn longer.

In all sites, the amount of direct sun and the sun’s position in the yard change as the day progresses and through the seasons.  The best way to determine sun exposure of your yard is to simply observe your garden. How much sun is in your yard, or a particular area of your yard throughout the day …as areas that are in sun in the morning may be in shade by the afternoon…and throughout the year.  Some yards are sunnier than others as a result of their exposure but there are other factors that affect sunlight, such as fences, tree canopy and shade-casting buildings. The key is to observe what you have throughout the day and to work with that.

Sun exposure, however,  does not say it all about growing conditions.   The direction your yard faces gives it particular properties throughout the year. A north-facing garden, or border in front of a north-facing fence, will receive little sun in winter, remaining cold and damp, but temperatures will be more constant than in a south-facing area that is warmed after a sunny winter day, only to be chilled at night.  A border by a sunny wall or fence will be far warmer and drier than one in the shade, perhaps beneath a tree, which is likely to be more humid with a more even temperature range.   There are advantages to shade…these gardens are cooler, have a more humid microclimate, and are less prone to drought.  Even within a single garden, you may notice great differences in the growing conditions.  The key is to work with what you have. In doing so, gardeners can capitalize on differences; even in small areas, which allow you to grow a wider range of plants.

Growing roses: Understanding the sun and shade patterns of the garden is important, but only part of the equation.  The second part is understanding what conditions the particular plant needs to thrive.   Typically, roses thrive on direct sunlight. For best results, a minimum of four to six hours of direct sunlight is recommended.  However, even when planted against a north wall roses can still perform well as long as they are in an otherwise light and airy aspect.

But remember, not all roses are the same. There are climbers, shrub roses, floribunda, and the more high maintenance tea roses.  Some roses can get by with partial sun, which is defined as somewhere between three and six hours of exposure per day. Be sure to do your research on what rose you are growing, so you will know what yours needs, in terms of both light exposure and other important growing conditions.

Happy gardening.

You may also wish to read our Gardening Guide on Pruning Roses and a previous question: https://www.torontomastergardeners.ca/askagardener/roses-to-grow-in-part-sun/

October 23, 2022

Toronto Master Gardeners