By Joe Pearl
With the amount of rainfall this winter in the deserts of the Southwestern United States, coupled with early high temperatures, here comes an explosion of vivid colors in and around our deserts. To pick out one plant in particular to talk about is a bit of a challenge, but here goes.
What about the brittle bush, or the desert marigolds, or any of the globe mallows, or the popping Penstemon? There are so many options to choose from; that it is a tough decision. Then there are the annual wildflowers that are popping up darn near everywhere. Purples, blues, yellows, oranges, whites, take your pick.
So, lets’ go with the Penstemon varieties. With so many different varieties out there for both the homeowner as well as the landscape contractor, almost any of the available plants make great additions to the landscape.
Being a relatively hardy plant, growing in zones from 4 – 10, they can tolerate temperatures in the freezing zones to the downright sultry hot days of the deserts of southern Arizona. Although they are not truly happy in those frigid temperatures, as long as they receive some protection, they will survive. As for the hot, hot days, they actually are happy if given a bit of shade in the later parts of the day.
Having over 250 different varieties (with some not-so-readily available, but out there), makes the adventurous landscaper become a hunter of the oddball varieties. They can be found, and once found, through experimenting, they can be planted in their ideal location. Whether it be an intensely hot location or a spot with good afternoon shade, this is the “trial and error” adventure. Isn’t this what landscaping fun?
Another really cool thing about growing Penstemon, is the sizes that a mature plant with blooms can reach. From the P. cobaea – 12-18 inches in height to the P. barbatus, up to six feet tall, there is a species that will suit any space. One can’t go wrong by using Penstemon in a native landscape.
As for locations and soil conditions for these desert beauties, 
they prefer a well drained soil, somewhat sandy, if possible. At the same time, these plants can be seen growing out of a crack in a rock outcropping. This will only make a person wonder why did they go through all the work to improve the soil condition, when these plants seemingly can appear from a crevice!
One of the best features about growing them is that they will propagate easily from seed. In other words, do not weed around them once they are done blooming and going to seed because the little sprouts that are being removed are highly likely to be seedlings. Let them grow, and spread. Enjoy these easy-care desert dwellers.
Plants them all over the place! That’s right, everywhere. In the spring, it will be well worth it. They look awesome when they pop up in between a planting of blackfoot daisies, or other low-growing groundcover plants. Even in pots, they can and often are treated as annuals (in certain areas).
Penstemon is a great plant for the Southwest. It will surprise people when it blooms on and off throughout the summer, although the spring is when it will be at its best. This is a great time of year to make your selection. Tall or short, dazzling bright or pale pastel, there is a Penstemon for every place!
Joe Pearl is a horticulture consultant in Mesa, AZ.