My yuccas grow well in red clay soil. You don't want to mix sand into clay soil. But you certainly could mix it into your gravel. Isn't it humid in Virginia? I don't know how well desert plants do in humidity.

My land has areas of sandy soil and areas of red clay soil. The native prickly pear only seem to grow in the sandy soil. The yuccas seed themselves all over, growing in both types of soil.

Lorna

Jim,

You have to remember that a desert is defined by the quantity of rain the area gets, usually less than a foot, not necessarily the types of plants grown. The native plants of a desert, either low or high, have developed the ability to conserve water during dry periods. Some store water, like cactus, yuccas, etc. and some slow down their metabolism, like sage, mesquite, etc. All of these will grow in most areas of the country, just don't supplement natural rain.