Gardening for Real People, II: Sun and Shade

The guidelines you get in most gardening books, or on the little plastic spiked tags that come with your plants from the shop, are usually very cut-and-dried about the plants' sun requirements: "Six or more hours of sun per day," for instance, or, "No afternoon sun."

But the messy conditions of the real world make nonsense of such simple prescriptions. Four hours of full sunshine and another eight of dappled sun under light shade may deliver more light to your tomatoes than the six hours of full sun they supposedly require. A bit of sun slanting in under taller trees late in the afternoon is unlikely to burn the leaves of your rhododendrons. Nearby glass or a white structure may reflect a good deal more light onto your plants than they receive directly. And what's more, the listed figures are the optimal conditions. But plants strive to survive, and can often get by on something far shy of optimal: I have seen backyard tomato gardens that couldn't have gotten more than two or three hours of direct sun a day, but where the tomatoes looked fine.

Another thing of which to take note is the time of year. In one of my gardens I was planting in June, and did not stop to consider, in choosing where to site plants, that the sun was at its absolute peak. Within two months spots that I had thought were sunny were in deep shade for most of the day. This is an especially relevant consideration for seasonal plants. Daffodils, for instance, need sun... but really only in the spring. Thus, you can plant them under deciduous trees, in places where sun-loving, summer-season plants could not possibly get by.

A great clue to what will survive where is what is already surviving where. Is there grass growing in a spot? Then that spot is at least a "partial sun" spot. Ferns? The spot is fairly shady, and will support hostas or astilbe fine. No ground plants at all? Then that's deep shade.