Plantopedia

Helianthus annuus (Sunflower)

Scientific Name

Helianthus annuus L.

Common Names

Sunflower, Grand Soleil (French), Tournesol (French), Sonnenblume (German), Girasole (Italian), Himawari (Japanese), Haebaragi (Korean), Girassol (Portuguese), Girasol (Spanish), Alizeti (Swahili), Solros (Swedish)

Synonyms

Helianthus annuus subsp. annuus, Helianthus annuus var. annuus, Helianthus annuus f. annuus, Helianthus aridus, Helianthus aridus var. aridus, Helianthus erythrocarpus, Helianthus indicus, Helianthus jaegeri, Helianthus lenticularis, Helianthus macrocarpus, Helianthus macrocarpus, Helianthus multiflorus, Helianthus ovatus, Helianthus platycephalus, Helianthus tubaeformis

Scientific Classification

Family: Asteraceae
Subfamily: Asteroideae
Tribe: Heliantheae
Genus: Helianthus

Flower

Color: Yellow and brown
Bloom Time: August to September

Description

Helianthus annuus is an annual herb, up to 10 feet (3 m) tall, with an erect, unbranched, rough-soft-hairy stem. The leaves are broad, coarsely toothed, rough and mostly alternate, up to 15 inches (40 cm) long. The flower is up to 15 inches (40 cm) in diameter and is actually a flower head of numerous small individual 5-petaled flowers (florets). The outer flowers which resemble petals are called ray flowers. The flowers in the center of the head are called disk flowers. The ray flowers are tongue-like and yellow in color, and the disk flowers are small, tubular and brownish. The fruit is long, flat-oval, slightly angular, smoothly haired–virtually glabrous cypsela, usually tipped with 2 withering bristles.

How to Grow and Care

If you decide to add Sunflowers to your garden, there are a few things you will want to keep in mind.

First of all, they are called sunflowers for a reason. They need sun. Make sure that the location you choose for your Sunflowers gets full sun.

Second, you do not need to worry about soil too much. They are not picky about the conditions of the soil, but they are plants. They will do better in better soil.

Third, Sunflower seed shells do contain a substance that is toxic to grass. So, you will need to either harvest the Sunflower heads before the seeds begin to fall out or you will need to plant your Sunflowers in a location where you do not mind any nearby grass being killed.

Fourth, keep in mind the height of the Sunflower variety you have chosen. A giant, twelve-foot variety will end up acting very much like a small tree and may shade the surrounding flowers… – See more at: How to Grow and Care for Sunflowers.