Companion Plants for Plumbago

Ornamental Grasses

• Ornamental grasses make great companion plants; their roots don’t compete for moisture or nutrients, they require little pruning or fertilization and most species don’t overgrow their bounds. Purple fountain grass (Pennisetum setaceum) grows from 3 to 4 feet tall and is hardy in zones 9 and 10. This ornamental grass, which can be grown as an annual, thrives in full sun and tolerates a variety of soils. It grows in an arching clump of red-purple foliage and produces pink-purple inflorescences from summer through late fall. New Zealand flax (Phormium texax) grows in 9-inch-tall clumps of wide, tapered foliage. Hardy in zones 8 through 10, this grass comes in a range of cultivars, from the copper, pink, white and yellow-striped Maori Queen to the dark purple-red Rubrum. It grows well in sunny sites with well-drained soil.

Shrubs

• Choose shrubs less than 6 feet tall so as not to create shade for your plumbago, and allow adequate space in between plants to avoid root competition. The century plant (Agava americana) is hardy in zones 9 through 10. This evergreen, which grows from 3 to 6 feet tall, thrives in sunny, well-draining sites and tolerates drought and salt. This shrub has long, blue-green fronds edged with small, curving spines. It blooms with yellow-green flowers. The pigeon berry (Duranta erecta) is also hardy in zones 9 to 10. Pigeon berry, an evergreen, grows to 6 feet tall with a similar spread and flowers in spring with white-blue blossoms, followed by yellow fruits.

Ground Covers

• Ground covers can grow around — and even in the slightly shaded spots beneath — a plumbago. These low, spreading plants help prevent erosion and weed growth. Purple heart (Setcreasea pallida “Purple Heart'”) grows from 6 to 12 inches tall and spreads into a mat of striking purple foliage. Hardy in zones 9 through 11, this spreading plant blooms with pink flowers and thrives in sun to partial shade and moist, well-draining soil. Dwarf jasmine (Jasminum parkeri) adds fragrant, yellow flowers to the landscape in early summer. This deciduous shrub grows to 12 inches tall with a 30-inch spread. It is hardy in zones 9 through 10 and grows well in full sun to partial shade and a variety of soils.

Perennials

• Sun-loving perennials add color to the garden through the growing season. Compatible species include gerbera daisies (Gerbera jamesonii), a 18-inch-tall perennial that blooms with red, pink, yellow and salmon flowers from early summer to late autumn. Hardy to zone 8, these bright plants grow well in sunny, well-draining sites. Brazilian verbena (Verbena bonariensis ) also blooms from summer through frost. This 4-foot-tall perennial produces purple flowers that attract butterflies. It thrives in sunny, well-drained sites.