Leafing again: the strange case of the ocotillo

One of the odder native residents of the Sonoran desert is the ocotillo bush. It typically consists of several spindly branches, vertically striped and spiny, up to 20 feet tall, that are leafless for long periods, only to sprout thick lines of small leaves within a few days after a rain.

Ocotillo branches with few leaves

Its desert adaptation of dropping leaves and playing possum is so complete that ocotillo plants for sale, in their leafless phase, with their branches tied in a bundle and roots bare, look thoroughly dead.

Ocotillo branches with many leaves

In the spring, they produce numerous red tubular blossoms at the ends of the branches that attract insects and birds of many species. They make great landscape plants because of their sparse sculptural look, and extremely low water requirements, and striking seasonal changes.

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Choose native plants for your desert landscape

One way to figure out what plants will be suitable and attractive in your desert landscaping is to go to a nearby natural area and see what is growing wild.

Make sure you select a location that is similar to yours in exposure, dryness and altitude.

Take photos or make a list of plants you find attractive. Never dig up native plants! They are fragile and rare, and in most places it is illegal to do so.  Almost everything you will see is available in plant stores. Photos will also help you arrange your landscaping, showing which plants grow together, and how much space they need.

Then go to the web or in plant books to learn about the plants you have found, or take your photos to a local nursery that specializes in native plants, and decide which are for you.

The variety of desert plants is surprising: cacti, shrubs, vines, spring-flowering annuals, many kinds of perennials. A big virtue of native plants is that they  require little in the way of extra water and plant food, and are easy to maintain.

One thing to keep in mind about native plants–some of them grow very slowly, so it may take a while for your landscape to mature. But there is nothing to match their beauty, and their ability to attract native fauna.

Strangeness in the desert soil: Caliche

Here’s one way to encounter caliche. Some friends pulled over one night in the New Mexico desert and camped in their truck. Happily for the desert, there was rain in the night. Unhappily for the humans, the next morning they found themselves surrounded by a huge pond of extremely slippery ankle-deep goo. Only after a long dirty struggle were they able to push their truck back onto the road. Caliche is what allowed a mudbath to form in the middle of the desert.

Another way to discover caliche is to dig a hole almost anywhere in the desert. Soon, inches or feet deep, you’ll hit a layer of what seems to be cement, even in places where you know there’s never been any construction.

What you’ve found is caliche, a white layer of soil, rich in calcium carbonate, clay, and other minerals that have been driven down into the ground by the hard infrequent desert rains, until the minerals form an often impervious layer of soil, also known as hardpan.

Wikipedia can tell you more.

When rain falls on an area with dense caliche, rather than sinking into the soil, the water runs off, if it can find a channel, sometimes causing the surprising desert flash floods, because so little water is absorbed into the ground. Or it puddles up, creating a sea of mud.

Digging a simple hole can require a pickaxe. Since the calcium carbonate can be alkaline enough to harm plant roots, planting in an area with caliche means that you may have to add conditioners as well as nutrients to the soil– and make sure there is drainage, even if that means digging a drainage hole through the caliche.

The Arizona Master Gardener, a great source of information, gives details of how to deal with it.