Most annual flowers require consistent moisture throughout the growing season for adequate growth and bloom. However, there are a few annuals that perform well in dry weather. While other annuals are suffering from a lack of moisture, these annuals will flower profusely without a significant rise in the water bill. All of these drought tolerant annuals will require water initially to establish a good root system. Once established, however, they require little watering. All perform best in full sun with well-drained soils.
Possessing fine textured foliage and yellow daisy-like flowers, Dahlberg Daisy (Dyssodia tenuiloba) is an excellent annual for edging and containers. The small, dainty flowers measure 1/2 inch in diameter. Plant height ranges from 6 to 8 inches with a 15 to 18 inch spread. The Dahlberg daisy never seems to stop flowering even in the hottest and driest of conditions.
Even in the severest of droughts, Rose Moss (Portulaca grandiflora) can take the heat. This succulent annual is often used as a groundcover or in containers. Plants rarely grow taller than 6 to 8 inches. Flowers are available in a wide range of bright and pastel colors with single or double flower forms. This native of Brazil is known for tolerating the difficult locations. If rose moss can't tolerate dry summer conditions, nothing can.
Globe Amaranth (Gomphrena globosa) has clover-like flower heads. The globe-like flower heads are available in white, pink, lavender, yellow, and red. This old-fashioned garden plant is a favorite of many gardeners due to its durability, use as a cut and dried flower, and its tolerance to poor sites. Its popularity as a dried flower is richly deserved since the flowers retain their color for long periods. Height ranges from 9 to 24 inches with a 10 to 12 inch spread.
Dusty Miller (Senecio cineraria) is one of the few annuals grown for its foliage rather than of its flowers. The silvery-gray foliage of dusty miller is an attractive addition to beds, borders, edging, and containers. Leaf textures vary among cultivars. 'Cirrus' has rounded leaves while 'Silverdust' or 'Silver Lace' leaves are finely divided. Plants range from 8 to 16 inches tall. The compact bushy plants prefer hot and dry summer conditions. Avoid wet sites. Plants tend to rot in wet locations.
For another heat and drought tolerant daisy, try Gazania (Gazania rigens). Flower colors include yellow, orange, bronze, pink, white, red, and various combinations. Many have darker centers. Flower heads are 2 to 3 inches in diameter. Growing in basal rosettes, the dandelion-like foliage of gazania is dark green with white, fuzzy undersides. Plants range from 6 to 12 inches tall. Flowers tend to close at night and reopen the next morning.
For something with a little more height, Spider Flower (Cleome hasslerana) is an excellent choice. Flowers are pink, lavender, or white flowers. The extended stamens (pollen-bearing organs of the flower) give it a spider-like appearance. Leaves are palmately compound and sometimes spiny at the base. While plants respond to abundant moisture, they are tolerant of dry, hot conditions as well.
Melampodium (Melampodium paludosum) may seem like an exercise in phonics, but it is also an excellent heat and drought tolerant annual. The small, golden-yellow daisy flowers literally smother the 8 to 10 inch mounding plants all summer.
Another commonly available drought tolerant annual is Periwinkle (Catharanthus roseus). Periwinkle possesses glossy, dark green foliage and pink, salmon, lavender, or white flowers. The flowers often have contrasting centers or eyes making them stand out in the garden. Plant height ranges from 4 to 12 inches with an equal spread
Other drought tolerant annuals include: Marigold (Tagetes sp.), Cockscomb (Celosia sp.), Cosmos (Cosmos sp.), Sunflower (Helianthus sp.), and Zinnia (Zinnia sp.). Don't let dry weather stop you from having flowers in your garden. The aforementioned annuals will tolerate the heat and drought better than we will.
This article originally appeared in the May 12, 2000 issue, p. 51.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on May 12, 2000. The information contained within may not be the most current and accurate depending on when it is accessed.