If you don’t know much about plants that thrive here in the Valley, it can be easy to get confused over how to properly care for the different things in your Phoenix or Scottsdale landscaping. Trees and shrubs are a lot more straightforward than cacti and succulents. They are instantly identified by their woody trunks and stems, but when you aren’t so sure what those plants without leaves in your yard are, its very easy to water too much or too little.
First of all, cacti are succulents. Succulents indigenous to the Americas. They aren’t native anywhere else in the world except the western, arid regions of North and South America. Cacti also have their own class in the world of botany, while succulents do not. Some succulents we use here in our landscaping originated in the Americas, and others on the other side of the Atlantic. Hmm… why is this important? Because while they adjust to the extreme temperatures we have here in the desert, natural moisture conditions where they are natives may differ from ours. And then there’s the fact that a plant forced into survival mode will never be beautiful, which is what we need from the things planted in our yards.
Everyone knows that a cactus has spines, or thorns as some might see the prickly part to be, but some succulents also have somewhat similar features. So, how do you know if it’s one or the other? Only cactus spines grow out of an areole, a dimple or knob that an array of spines grow out of, be it 1 spine or a dozen. There are succulents, like Euphorbia, that look for all the world like a cactus, and can even have the word cactus in their name – but they’re not cacti, and the spines do not sprout from an areole. In fact, the spines on a Euphorbia are the dried remains of the leaves, as seen in the image on the right/bottom below. Look at the difference between the second image and the first one of the spines on a Prickly Pear cactus.
Cactus do not have leaves… ever, because those spines, at least the bottom one in an array, are their leaves. And their areoles are always in a pattern – like columns, and rows, where succulents produce spines along trunk ridges, leaf edges, or the bumps that look like they will produce spines never do.
Here’s a group of plants that has representatives originating from many places around the world. It includes cactus, though a botanist would never lump them in with the rest, a horticulturalist will. To keep this in focus for what you need to know about your desert landscaping in Phoenix or Scottsdale, we’ll stick to those non-cactus succulents that are hardy in this climate. Mainly, they are Aloes and Agaves, which look a lot alike, but we also have a variety of Echeveria, Euphobia, Hesperaloe (Yucca), and others that do well in the Valley.
Aloe and Agave similarities separate inside the leaves. Aloe leaves are super fleshy, because it’s where the plant stores water. Agave leaves are tough and stringy – the water is not stored in the leaves. What does this vast difference mean? A fleshy succulent has leaves that withstand dry spells, while one with stringy, fibrous leaves stores water in it’s roots. If the water available to the plant is concentrated in the roots, then the leaves will die faster than those with fleshy leaves. So repairing the beauty to fibrous plant that has gone without moisture too long means it must regenerate new leaves, while the fleshy one will plump back up. Both Yucca and Agave are fibrous, while Aloe, Echeveria, Euphorbia and cactus plants are not.
All xeriscaping plants are good for low-water landscaping, but some are better equipped naturally to deal with longer dry periods than others. They can’t all be watered on the same schedule with the same amount of added moisture. Your soil will have some influence on how often and how much you should water your plants to keep them in prime form. And the best way to water your Phoenix or Scottsdale landscaping is with drip irrigation at the roots. This puts the water where the plant can use it, and it’s not lost to the sun, heat, and wind.
First image courtesy of Curt Gibbs, CCby2.0