Culture
Gazania linearis is winter hardy to USDA Zones 5 to 9 where it is easily grown in sandy to average, well-drained soils in full sun. Many of the other species of Gazania, including a large number of hybrids, are commonly sold in commerce today as plants that are winter hardy only to zones 9-11, and for the most part are grown in much of the U.S. as annuals. By contrast, G. linearis and its cultivars grow well throughout Zone 5, with established plants preferring consistent moisture but being able to tolerate some soil dryness, including brief periods of drought. Avoid soils that completely dry out in summer, wet soils, and heavy clay soils. Deadhead spent flowers to encourage additional bloom. Species plants are easily propagated by seed, summer cuttings or division. Sow seed in fall or winter.
Noteworthy Characteristics
Gazinia linearis, commonly called treasure flower, is a compact cold hardy herbaceous perennial that is native to grassy slopes and rocky cliffs in the Drakensberg Mountains of South Africa. It is a stemless flowering plant that produces a ground-hugging mat to 3-4” tall of linear to linear-lanceolate, entire to rarely pinnatifid, revolute-margined leaves (each to 4-5” long). Leaves are shiny green and glabrous to sparsely hispid above but white tomentose beneath, and are held in basal rosettes rising from stout woody crowns. Solitary, golden yellow, daisy-like flowers (each to 3” diameter) bloom in spring and summer on scapes rising slightly above the foliage to 5-6” tall. In frost free climates, flowers may bloom intermittently throughout much of the year. Ray florets are bright yellow, often with dark brown basal spots which form a showy narrow ring around the center disk of densely-packed yellow to reddish-orange disk florets. Flowers open with morning sun but close at night or on cloudy days.
Notwithstanding its attractive ornamental features, this perennial often spreads rapidly in a weed-like fashion in many areas around the world where it has been introduced. It is now listed as an invasive species in the State of California where it has primarily escaped cultivation and naturalized in native grasslands, coastal areas, roadsides and waste places.
Genus name possibly honors Theodore de Gaza (1398-1478), 15th century Greek scholar, who translated some important botanical works of Theophrastus from Greek into Latin. In the alternative, the genus name may come from the Latin word gaza meaning "treasure" in reference to the attractive flowers as memorialized by the adoption of the common name of treasure flower for this plant.
Specific epithet is in reference to the linear leaf of the plant.
‘Colorado Gold’ primarily differs from species plants by having silvery leaf undersides.
Problems
No serious insect or disease problems. Overly moist soils can lead to root and stem rot. Plants are sometimes affected by powdery mildew, bacterial leaf spot, fungal spots and crown rot. Thrips and mealybugs occasionally appear.
Uses
Valued as a low-growing ornamental. Mass in beds, rock gardens, border fronts or slopes. Ground cover or edger. Containers.