MISSOURI BOTANICAL GARDEN BULLETIN 109 



HELIANTHUS ANGUSTIFOLIUS 



One of the most showy perennials during the months of 

 October and November, or until the foliage and flowers are 

 killed by heavy frost, is the narrow-leaved sunflower, Helian- 

 thus angustifolius. This plant has a natural distribution in 

 open swampy land from Long Island to Florida, mainly near 

 the coast, and west to Arkansas and Texas. It varies in 

 height from three to eight feet. The heads are two to three 

 inches broad, with bright yellow rays and purple disks, and 

 are borne few, sometimes solitary, on the slender branched 

 stems. The leaves are long, very narrow, dark green above, 

 paler beneath, rough to the touch. 



Under cultivation the growth and habit of Helianthus 

 angustifolius are considerably changed. It branches nearer 

 the ground, the delicate dark green leaves making the plant 

 attractive for foreground planting during the entire growing 

 season until autumn when it becomes a mass of yellow flowers. 

 The flowers are very sensitive to the sunlight, changing their 

 position to face the sun during the day. While the native 

 habitat is a rich open swampy ground, the plant adapts 

 itself to the soil conditions of the ordinary garden border 

 provided there is not too much shade. 



Helianthus angustifolius is easily propagated from seeds. If 

 these are sown in November or December in a cool green- 

 house and the plants carried on in pots during winter and 

 planted out in their permanent positions after danger of 

 frost in the spring, the maximum of growth and flowers will 

 be attained the first year. If sown in the open ground in 

 the spring, however, full-grown blooming plants will not be 

 produced until the year following. Propagation may also be 

 accomplished by taking up the viviparous plants which form 

 around the base of the old stem after flowering and in the 

 spring planting them in the positions where the mature plants 

 are desired. They will then bloom the following autumn. 



While this plant was described by Linnaeus in 1753, it has 

 not yet become generally known as a garden subject. Its 

 graceful form, floriferous habit, ease of culture and propaga- 

 tion should make it a general favorite for foreground planta- 

 tions in shrubberies and for the hardy border. The color of 

 the flowers makes possible many attractive combinations with 

 the various species of white, blue, and purple asters whose 

 season of bloom corresponds to that of the Helianthus. 



In 1909 about twenty plants of Helianthus angustifolius 



