For hot, dry areas or a garden bed with no source of irrigation, plant flowers tolerant to drought. As small seedlings they will need coddling and constant care, just like any other seedling. But after they have been transplanted and are actively growing, these flowers will grow quite well without artificial watering, except in cases of extreme, prolonged drought.
A low-growing annual that thrives in dry areas, the moss rose (Portulaca grandiflora) has 2-inch flowers that resemble roses and finely divided foliage. Its flowers are rose, pink, orange, yellow, white or bicolored. It also is a somewhat prolific reseeder, although the seedlings are tiny and slow to get growing. Plant moss roses in full sun in well-drained soil. They will thrive in areas where other annual flowers shrivel up and die.
Flowering from late spring through fall, salvia (Salvia splendens) produces spikes of purple, white or red flowers with grayish green foliage. Salvia grows 12 to 36 inches high, depending on the variety. It is moderately tolerant to drought and an excellent choice for urban flower borders where artificial watering is not possible. Salvia grows best in full sun to partial shade.
A member of the amaranth family, cockscomb (Celosia argenta var. crista) gets its common name from the shape of its flowers: they greatly resemble the "headpiece" on a rooster. Also called celosia, they grow best in full sun and are moderately tolerant to drought. Although red is the most well-known flower color, it is also available in shades of yellow. Cockscomb grows 12 to 36 inches high, depending on growing conditions.