Plants vary in the amount of water they require and so you need to choose carefully if you? live in an area of low rainfall. The twelve flowers on this list all need some water, but are less demanding than many others. In addition to selecting the best plants for dry conditions it is important to water in the correct way and to apply a mulch to conserve moisture in the soil. The list of twelve plants to grow in a drought comes from an article by Stephanie Kriess which I found on The Master Gardeners website.

It is difficult to know what to do about investing in new plant material this year. In spite of fears of drought, it has been raining some this spring and I believe you can buy new plants and have good success with them this season. However, you must give careful attention to plant selection, placement and care. In fact with the increasing frequency of water shortages in this area over recent years, careful selection of drought tolerant plants should be the norm, rather than the exception.
There are many beautiful drought tolerant plants that are readily available in local nurseries and home/garden stores. They come in a wide range of colors and sizes. Some good perennials include:
Perennial Bachelors Button (Centaurea montana). This lovely rounded plant grows about 12 inches high and 12 inches wide. Its leaves are long and a silvery green. Flowers are blue and about 2 inches in diameter. With deadheading (removal of spent flower heads before they go to seed) Centaurea will bloom from May through September. The one downfall of this plant is that it spreads by underground runners and may also reseeds itself throughout the garden. You can take care of this problem by pulling up unwanted seedlings in the spring.
Daylily (Hemerocallis). We are all familiar with the daylily by now. There are more than 20,000 registered hybrids, in colors ranging from yellow, to red to deep purple. They range in height from 6 inches to over 30 inches. Most bloom only once per summer, but every year more repeat or continuous bloomers are being developed. The most famous and earliest repeat bloomer is ‘Stella d’Oro’. The foliage of daylilies stays attractive all summer, although the appearance of the plant does benefit from removal of spent flower heads and browning leaves. Daylilies generally need to be divided every 4 or 5 years.
Candytuft (Iberis sermpervirens) is a great spring-blooming low-growing plant for the front of the border. The flowers last for about 10 weeks. Its evergreen foliage is dark green and the flowers are pure white. The plants have a woody base and should be cut back severely every other year to insure that they do not get leggy.

See more at The Master Gardeners