There are around 150 mintage of helianthus ( Helianthusspp . ) , which go to the Asteraceae , or daisy , family unit of plant . Most untamed sunflowers are native to North America .
respect for their splashy sensationalistic flowers , sunflower may be annual , imply they endure for just one develop season , or perennials that come back every year in their hardiness zones .
Features of Sunflowers
Theflower headsof sunflowers are jazz ascomposite flowersbecause they feature individual shaft flowers , which give the appearing of blossom petals , around a disk made up of many flyspeck flowers take closer together . The flowers on the saucer become seedheads that produce seed savor by fowl .
Sunflowers get their name because young sunflowers shift throughout the day to follow the Dominicus as it impress across the sky . This movement of the helianthus heads is known as * * heliotropism , * * and it helps make the plant more attractive to pollinators . Therefore , whenever you plant sunflowers , you should do so in full sun .
While sunflower are known for their summit — many can be up to 10 feet marvelous — there is also a wide-eyed variety of helianthus that are naturally short . The leaves of a sunflower are unremarkably rough in texture .
Sunflowers get their name because young sunflower plants shift throughout the twenty-four hour period to follow the sunshine as it moves across the sky .
Annual Sunflower Identification
The Helianthus species most people are familiar with is the common helianthus ( Helianthus annuus ) , a tight - grow annual plant life with heights between 5 and 10 foot . This is the species commonly tame commercially for sunflower seeds and as shortened flowers for bouquet . Common helianthus leaves may be up to 12 inches farseeing and have a emery paper - like texture .
hybridizing has yielded an classification of cultivars of the annual sunflower , including gnome cultivars that are 1 to 3 invertebrate foot marvelous and mammoth cultivar that may be up to 15 foot marvelous . The saucer of the common sunflower are usually coloured chocolate-brown or purple , while the rays may be yellow , mahogany or even bicolored .
Perennial Sunflower Identification
Many sunflowers are perennials that set out to bloom in late summer and early spill . Here are a few examples .
Western Sunflower
Despite what its common name suggests , the westerly sunflower ( Helianthus occidentalis , zone 4 to 8) is actually native to the key and easterly regions of the U.S. This metal money has orangish - lily-livered rays arranged around a yellow disc . This is one of the shortest helianthus species , with meridian between 2 and 4 feet .
The western sunflower is also fuck as the naked - caulescent helianthus because of the thin number of leaf on its stems .
Willow-Leaved Sunflower
The willow tree - leaved sunflower ( Helianthus salicifolius , zones 4 to 9 ) gets its name from its leaves , which are thin and droop like those of a willow tree . This metal money has promising scandalmongering rays environ a dark brown centre disc .
The willow - leaved helianthus is capable of produce more than 8 foundation tall , but has typical heights between 5 and 6 foundation .
Maximilian Sunflower
The Maximilian sunflower ( Helianthus maximiliani , zones 4 to 9 ) has icteric ray that surround a darker yellow-bellied magnetic disc . The flower are 2 or 3 inch all-inclusive and perched on hairy stems that may be up to 10 feet tall .
The leaves of the Maximilian helianthus have length between 3 and 6 inches and are usually narrow and folded in one-half lengthwise .
