If one of your concerns about xeriscaping is that your garden will look as barren as the Southwest desert, it only takes a little planning and time to ensure you have some color and texture from spring to fall. Of course, that’s easy if you have unlimited water and time.
But it’s also entirely possible and relatively simple to have continuous color using low-water plants. Here are a few suggestions:
Don’t give up on bulbs. Although you would think they use lots of water, they’re like the camels of the plant world, adapted or bred to store water and energy in their roots, stems or leaves. They also do best in well-draining soil. I’m lumping corms, tubers and rhizomes with true bulbs. Spring-flowering bulbs should need no water other than rain after established unless you have a really long dry spell, especially during growth and flowering. As long as you choose varieties recommended for your area and follow care guides for placement, mulching and dividing, you should be able to add bulbs to your xeric garden as desired. I love how iris and tulips bloom early as a sign of spring.
Choose one or two continuous, or nearly continuous, bloomers. I don’t know how a small shrub, especially a xeric one, can bloom in the late spring or early summer and hold those blooms all season. But I think the easiest way to plan a small xeric garden is to select one continuous bloomer you like, then build around it. For example, santolina usually blooms all summer, after one trim or shearing back in the spring. Since it has yellow flowers, you can then decide how you’d like to complement the low spreading shrub with other colors throughout the summer. By the way, it’s also evergreen, so you can consider how to complement the gray (silvery foliage) or green santolina with another evergreen or some hardscaping for winter interest. Other examples, depending on your zone, are gaura (Gaura linheimeri) or most salvias, though some might require deadheading.
Try a groundcover. You don’t have to replace your entire lawn with a groundcover, but you can add color with some well-placed xeric planting. Several thyme varieties require no water at all and are terrific at filling in spaces between pavers, rocks or stepping stones. You’ll get some green and tiny purple flowers when they bloom. A groundcover also can cool the roots of other plants that need a little help to survive hot summer days. Just remember that they spread, especially if you overwater them.
Supplement with a few annual seeds or containers. Satisfy your desire for early color and bloom variety each year with some annuals. Seeds are inexpensive, but are a little more water and time intensive. Or fill a designated area of your patio, deck or garden with a few containers with pops of color from annual bedding plants. You can decide when the color appears and what colors you want to complement your perennial blooms. Seeds sowed as soon as the ground warms will bloom later than many of your perennials. And many annuals continue blooming with or without pinching and deadheading. I love petunias in containers because they spread with little effort on my part and need no deadheading, just pinching off of spent buds every now and then to look their best.
It can be a lot of work to deadhead continuously. So it’s probably good to limit the number of annuals that need regular trimming of blooms to force new ones. But some xeric plants such as lavender and salvias will bloom a second time with one trim following the first bloom, so you get a late, bonus wave of color.
Some plants give you plenty of hints (Autumn sedum booms in fall!). But if you have limited space and experience, a xeric landscape designer can help you select the fewest plants possible for continuous bloom.