Annuals For The Dry Garden

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In the Mountain West, where water is both scarce and expensive, the days of flowerbeds billowing with thirsty annuals are gone. As we gradually made the transition from mesic to xeric gardening, the use of colorful annuals was the last element to follow suit.

Many of the annuals that we already grew were drought tolerant but we didn’t realize it. Plants like Petunia integrifolia (wild petunia), Zinnia angustifolia (narrow leaf zinnia), Portulaca varieties (moss rose), Nierembergia hippomanica (cup flower), Thymophylla tenuiloba (Dahlberg daisy), Verbena spp. and Eschscholzia californica (California poppy) have proven to adapt to pebbly soils that are low in organic matter. In fact, they are spectacular in the lean, dry soils of Colorado.

It’s rare to see these types of plants in mass plantings but they are finding their way into the xeriscapes and rock gardens of the region. The typical xeriscape or rock garden has a hearty blend of evergreen and deciduous elements that provide the back bone of the design but is often lacking in summer color. Tucking these drought-loving annuals in between permanent plants gives another whole layer of color, texture and beauty. This aesthetic is becoming more the norm as opposed to beds of petunias and geraniums.

I think that was a big hump to get over for many gardeners. What helped with the transition were the enormous water bills hitting their mailboxes every month! I still get a lot of “I don’t want those stickery yuccas and cactus.” With a little creativity and research, we can create a non-stickery, low-water landscape that has lots of color for our customer. On the other hand, some of us like the prickly plants!

Plants You Need To Know

Growing And Finishing These Plants

We grow a lot of desert annuals by direct sowing the seeds in 4-inch pots. In early to mid-March, we fill trays with potting mix, water them and sow a pinch of seeds in the middle of each. The trays go into a warm greenhouse to germinate. About a week after germination, the trays move to a cool (45 to 55°F) greenhouse to harden. By mid-April, the trays are moved outdoors and covered with frost cloth to finish. This produces a beautiful crop just ready for Mother’s Day!TGC

Kelly Grummons [] is co-owner and chief horticulturist of Timberline Gardens in Arvada, Colo.

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