By Scott Calhoun
When I got out my shovel to dig the first hole in my desert garden, I plunged it into the ground—or rather attempted to—only to have the shovel clank against the soil as if I’d hit solid rock. It wasn’t rock, but the compacted soil around my home, a mix of rock and tight clay. But it was almost as bad as rock, and I had to get creative to make the garden a success.
When you work in tough soils, the first step to success is choosing plants tough enough to grow in them. Plants such as the foothills palo verde (Parkinsonia microphylla), pictured above, grow well even in compacted, rocky soils. To plant, dig a hole the same depth as the container but three to five times wider. Don’t amend the backfill but break up the native soil and use it as backfill.
Tough desert plants prefer the highly mineralized soils native to most of the Southwest. In tough digging situations you may need a pick to break up the soil. If you are planting large trees or a large number of plants, consider renting an electric jackhammer with a spade bit.
Even tough perennials grow just fine in unamended desert soils. For example, damianita daisy (Chrysactinia mexicana) likes tough, mineralized soils, blooms exuberantly and gets by on scant watering.
Choosing rugged shrubs is also key to success. Plants such as the Baja fairy duster (Calliandra californica), pictured, are happy in infertile soils and add a blast of seasonal color to desert landscapes. Another good group of shrubs for difficult soils are Texas ranger (Leucophyllum).
Succulents, such as the red yucca (Hesperaloe parviflora), pictured, might be the champions of tough soils. They are adept at growing in conditions where their roots are constricted. They do like good drainage, so if you are planting in a clay-based soil, consider planting succulents (and cactus) on mounds, and amending the clay with gypsum.
So there you have it: You can conquer tough soils with tough plants, and maybe a pick and jackhammer, and some gypsum. How do you deal with the difficult soil in your garden?