These plants bear tubular flow- ers that flare into saucerlike or bell-like cups. The species listed here grow as a spreading mound or a ground-covering mat. All are covered with blooms during summer. Can be grown as perennials in the Lower South, cool-weather annuals in the Coastal and Tropical South, summer annuals elsewhere.
N. gracilis. Native to the Argenine desert, this species and its primary selection, 'Starry Eyes', endure hot summer, either arid or humid, growing into a mound 10 in. tall and 18 in. wide. Plant in sun, with good drainage. After the lavender-centered white bells fade, shear for more flowers. Perennial in the Lower South, (USDA 8) and warmer.
N. linariifolia (N. caerulea, N. hippomanica). DWARF CUP FLOWER. To 612 in. high and wide. Much-branched, mounding plant with very small, stiff leaves. Flowers are blue to violet. Trimming back plant after bloom to induce new growth seems to lengthen its life. 'Augusta Blue Skies' is a compact hybrid with lavender-blue flowers and improved heat tolerance. Plants may surprise you and overwinter in the Middle South, (USDA 7) and warmer.
N. repens. WHITE CUP. Bright green foliage forms a mat to 46 in. high, 2 ft. wide. White blossoms. For best performance, don't crowd it with more aggressive plants. Not as heat tolerant as N. linariifolia. However, plants can overwinter in the Middle South, (USDA 7) and warmer.
N. scoparia. TALL CUP FLOWER. Growing 12 ft. tall, favorites include 'Purple Robe' and the white 'Mont Blanc', usually sold as N. hippomanica. Plants may overwinter in the Middle South, (USDA 7) and warmer, so cut back, but don't pull them out at summer's end.
N. Summer Splash series. Grows 1012 in. tall and 12 ft. wide in both white and blue. Tolerant of heat and humidity.