Terrestrial Invasives

Verbesina encelioides

Verbesina encelioidesWild Sunflower

Common Name 
Wild Sunflower
Legal Status 
Emerging Weed

V. encelioides is an erect annual reaching 30 cm and up to 160 cm and grows from a taproot system. Leaves are toothed or lobed and have two growth patterns: lower leaves are opposite and triangular, while the upper leaves are alternate and lance shaped. Fine white hairs are present on the underside of leaves and on the stem. Flower heads are bright yellow and found on elongated stalks and resemble small sunflowers, and are 2.5 to 5 cm in diameter. This species originates from North and Central America.

Flower head
Wild sunflower
Wild sunflower
Seeds in the flower head
Where does this species come from? 
North America (i.e. southern and western USA and northern and central Mexico).

Why is it a problem? 
This species invades roadsides, cultivated and fallow land, disturbed sites and sandy watercourses. It is considered as an intrusive invader, which spreads over fertile land and prevents development of any other indigenous species due to its high propagation and density. It has a potential to take over habitat of indigenous plants. This plant has poisonous toxins that are a threat for grazing sheep and cattle.
Means of reproduction? 
The plants reproduce by both self and cross-pollination. It produces large amounts of seeds in autumn/early winter, with each flower being able to produce over 300 seeds.