Understanding shade in the desert

Gardening here in the desert makes you appreciate shade. When I bought a house, I insisted that the back yard face east. That way, you get morning sun, but the house itself shades the yard in the afternoon, in the hottest part of the day. That's the easy part about understanding shade in your garden - the sun comes up in the east, goes over your house, and sets in the west. Here in the Phoenix, Arizona area, it can be uncomfortably hot even in the early morning, and brutally hot by late afternoon.

But there is another aspect of shade that you have to consider - how the sun moves from south to north as the seasons change. The shade that you see in the picture is coming from a north-facing wall and patio in April. In the winter that shadow was much longer, because the sun was farther south. By mid-summer, that shadow will be much shorter, as the sun moves towards the north. In the middle of the summer, that is, after the summer equinox, the shadow will get longer as the sun begins to move south again.

Summer is on its way, so the shadow will get shorter every day until the equinox, when it reaches only to about Macintosh's doggy-door. So plants that have gotten a lot of shade up to that point will suddenly find themselves without it, at least in the morning. And it will happen at the absolutely hottest time of the year.