Cyanthillium cinereum aka Little Ironweed

Cyanthillium cinereum is extremely easy to grow - so easy it's considered a weed in 47 countries across Asia, Africa, Australia, and the Americas. This hardy plant thrives in disturbed soils, tolerates semi-arid and partially saline conditions, and can colonize a wide range of environments from roadsides to pastures. It requires minimal care once established and readily self-seeds.

Cyanthillium cinereum requires moderate watering. While it can tolerate semi-arid conditions and brief dry spells, it performs best with regular moisture. In its natural habitat, it grows in both wetland and non-wetland areas, indicating flexibility in water requirements. Allow soil to dry slightly between waterings but don't let it become completely parched.

Cyanthillium cinereum prefers sandy-loam soils with acidic pH between 4 and 6, but it's highly adaptable and can grow on a wide range of soil types. The plant even tolerates partially saline conditions. Good drainage is beneficial, though it can handle occasional wet conditions as it's found in both wetland and non-wetland habitats.

Cyanthillium cinereum requires full sun to thrive. As a plant that typically grows as a weed in open, disturbed areas like roadsides, fields, and waste grounds, it has evolved to maximize sunlight exposure. It will not perform well in shaded conditions and should be planted where it receives direct sunlight throughout the day.

Cyanthillium cinereum propagates readily from seed. The seeds are equipped with fluffy white pappus hairs that aid wind dispersal, allowing the plant to spread easily. Germination typically occurs within 8 to 33 days. Simply scatter seeds on the soil surface in a sunny location and keep moist until germination. The plant self-seeds prolifically once established.

Cyanthillium cinereum is a fast-growing herb that typically reaches 15-80 cm (6-31 inches) tall, though specimens up to 1 meter (3 feet) have been recorded. The plant has an erect, slightly branched growth habit with a spread of approximately 30 cm. It grows quickly and can form dense patches when conditions are favorable, completing its lifecycle in a single growing season in most climates.

Cyanthillium cinereum produces attractive composite flower heads arranged in loose, flat-topped clusters (panicles) at the branch tips. Each head contains 15-30 small disc florets in shades of purple, pink, mauve, or occasionally white, measuring about 3-5 mm in diameter. Flowering occurs primarily in summer to autumn, though tropical plants may bloom year-round. The flowers are wind-pollinated and develop into small brown achenes with fluffy white pappus for wind dispersal.

Cyanthillium cinereum is primarily wind-pollinated, which is somewhat unusual for the Asteraceae family where insect pollination is more common. The small disc florets produce pollen that is carried by air currents to other flowers. Under favorable conditions, the plant flowers and sets seed continuously for many months, ensuring prolific reproduction.

Cyanthillium cinereum is native to tropical Africa and tropical Asia, including India, Sri Lanka, Indochina, Indonesia, Arabia, and extending to Australia and Pacific islands. The species has since naturalized extensively across Mesoamerica, tropical South America, the Caribbean, and parts of the southern United States including Florida and Hawaii. It thrives in the seasonally dry tropical biome.

Cyanthillium cinereum grows exclusively outdoors and is not suitable as a houseplant. It requires full sun and is hardy in USDA zones 9-12, meaning it needs frost-free or near frost-free conditions. The plant thrives in disturbed soils at elevations from sea level to 1,300 meters (4,300 feet). In temperate climates with frost, it can be grown as an annual during warm months.

Cyanthillium cinereum is a tropical to subtropical plant that does not tolerate frost. It thrives in warm temperatures typical of USDA hardiness zones 9-12. The plant grows best in consistently warm conditions and will die back or perish entirely if exposed to freezing temperatures. In its native range, it grows from near sea level to elevations of 1,300 meters where temperatures remain mild.

Cyanthillium cinereum is notably resilient to most pests and diseases, which contributes to its weedy nature. However, it can serve as a host plant for the Cuban slug and is known to transmit the tobacco leaf curl virus and root-knot nematode to agricultural crops. These characteristics make it a concern in agricultural areas where it may spread pests and diseases to nearby crops.

Yes, Cyanthillium cinereum is edible with a 3 out of 5 edibility rating. The young, tender leaves have a slightly bitter taste and are cooked as a potherb or added to soups in parts of Africa and Asia. In Kenya, the plant is sometimes cultivated specifically as a leafy vegetable. The leaves contain vitamins A, B, and C, along with various minerals including calcium, iron, magnesium, and potassium.

Cyanthillium cinereum has extensive use in traditional medicine, particularly in Ayurveda where it's known as 'Sahadevi.' Traditional applications include treating fevers, skin conditions, respiratory ailments, gastrointestinal disorders, and as a diuretic and anti-inflammatory agent. In Thailand, it's used for smoking cessation. Modern research has confirmed anti-inflammatory, antimicrobial, antioxidant, antidiabetic, and anticancer properties in plant extracts. The whole plant, leaves, and seeds are all used medicinally.

Beyond food and medicine, Cyanthillium cinereum has limited other uses. The seeds yield a fatty oil that has some medicinal applications. In some regions, the plant has been studied for potential use in smoking cessation programs. Due to its weedy nature, it is not commonly cultivated for ornamental purposes.

The toxicity level of this plant has not been officially confirmed by Ploi. If there is a possibility of ingestion of plant material with an uncertain toxicity by you, a family member, or a pet, it is advisable to seek the assistance of a medical professional.