Chrysanthemum

Lore & Background

Chrysanthemums are perennial herbaceous flowering plants, sometimes taking the form of subshrubs, belonging to the family Asteraceae. Their leaves are arranged alternately along the stem and are typically divided into leaflets; they may be pinnatisect, lobed, or serrated (toothed), though they are rarely entire. The leaves are connected to stalks that have hairy bases. The plant’s inflorescence is a compound structure, consisting of an array of several flower heads, or occasionally a solitary head. Each head is supported by a base covered in layers of phyllaries. The ray florets, arranged in a simple row, are white, yellow, or red, while the disc florets are yellow. Pollen grains measure approximately 34 microns. The fruit is a ribbed achene. Native to East Asia and northeastern Europe, most species originate from East Asia, with the center of diversity located in China. As a late-season flower, chrysanthemums are associated in the Northern Hemisphere with the month of November. The genus was first formally described by Linnaeus in 1753, originally containing 14 species. A ruling by the International Botanical Congress in 1999 changed the defining species of the genus to *Chrysanthemum indicum*, restoring the florist’s chrysanthemums to the genus *Chrysanthemum* after a period of taxonomic splitting.

Reader's Guide

Chrysanthemums are perennial herbaceous flowering plants in the family Asteraceae, native to East Asia and northeastern Europe, with their center of diversity in China. They bloom in autumn and are associated in the Northern Hemisphere with the month of November. The name derives from Greek words for gold and flower. The genus was first formally described by Linnaeus in 1753, though its taxonomic history is complex: the genus once included many more species, but was split into several genera, with the economically important florist’s chrysanthemums moved to *Dendranthema*. A 1999 ruling by the International Botanical Congress changed the defining species to *Chrysanthemum indicum*, restoring the florist’s chrysanthemums to the genus. The leaves are alternate, divided into leaflets, and may be pinnatisect, lobed, or serrate, with hairy-based stalks. The inflorescence is an array of several flower heads or a solitary head, with a base covered in layers of phyllaries. Ray florets are white, yellow, or red, while disc florets are yellow. The fruit is a ribbed achene. Cultivation began in China as early as the 15th century BCE, and over 500 cultivars were recorded by 1630. By 2014, over 20,000 cultivars existed worldwide, with about 7,000 in China. In Japan, cultivation began during the Nara and Heian periods and flourished in the Edo period, producing many flower shapes and colors. The imperial crest of Japan is a chrysanthemum, and the monarchy is called the Chrysanthemum Throne. Chrysanthemums entered American horticulture in 1798 when a cultivated variety was imported from England.

Did You Know?

• The name 'chrysanthemum' comes from Ancient Greek words for 'gold' and 'flower'.
• Chrysanthemums were first cultivated in China as early as the 15th century CE.
• The imperial crest of Japan is a chrysanthemum, and the monarchy is called the Chrysanthemum Throne.
• Pyrethrum, a natural insecticide, is derived from chrysanthemum flowers.

Ancient Chinese Origins and Medicinal Legacy

For over two millennia, the chrysanthemum has held extraordinary significance in Chinese culture, long before reaching European soil. Its earliest role was medicinal rather than decorative. The foundational pharmacopoeia, the Shennong Ben Cao Jing, placed it among the highest tier of therapeutic substances, linking it to the ancient pursuit of immortality. Prolonged use was said to unblock the circulation of blood and qi, ease the body, retard ageing, and extend life. The concept of "lightening the body" was tied to the mythological ideal of celestial Immortals who could soar and ride the clouds. It was not until the Jin and Tang dynasties, around the fifth century, that the chrysanthemum was cultivated as an ornamental, though it continued to serve dietary purposes. Centuries later, herbalist Li Shizhen documented a hundred cultivars, noting their ability to dispel heat and toxins and sharpen vision. By the early twentieth century, roughly two thousand cultivars were known in China.

European Discovery and Botanical Taxonomy

The chrysanthemum's journey into European botanical science unfolded over more than a century. Though the flower had been known in the Netherlands since the mid-seventeenth century, widespread horticultural adoption did not occur until the 1800s. Ramatuelle carefully distinguished this new cultivar from Linnaeus's Chrysanthemum indicum, which bore small yellow heads, and proposed the name Chrysanthemum morifolium. The horticulturist Wilhelm Miller later clarified that the florist's chrysanthemum was a blended product of C. indicum and C. morifolium, both wild species native to China and Japan. Today the global complex of cultivars is estimated at twenty to thirty thousand, with more than a thousand varieties established in Europe alone since the nineteenth century.

Physical Form and Botanical Structure

The chrysanthemum grows as a perennial herbaceous or slightly woody plant, typically reaching thirty to ninety centimetres in both height and spread, with upright stems forming a dense, rounded tuft. Its branches are silky and covered in a fine short down, giving the whole plant a thick, leathery texture. The leaves are the most reliable identifier of the species: broad and ovate in outline, wedge-shaped at the petiole, and exceeding one hundred and fifty millimetres in length. Lower leaves are deeply plumed, while those higher on the stem become increasingly entire. They are alternate, lobed, pinnatifid, and toothed, fleshy in texture, and dusted with grey hairs. When crushed or wrinkled, they release a strong, distinctive scent. The flower heads are radiate, composed of peripheral female florets with zygomorphous ligules surrounding central actinomorphous, tubulated, bisexual florets. External bracts are herbaceous with a narrow margin. In complex inflorescences, numerous cup-shaped partial clusters group together. Tongue flowers appear in shades of green, white, yellow, pink, and purple, ranging from simple daisy-like forms to dense pompom doubles. The plant initiates blooming only when day length falls below fourteen hours. Over a millennium and a half of cultivation, tens of thousands of cultivars with vastly different head shapes, sizes, and colours have been produced.

Horticultural Classification and Artistic Cultivation

In North America, chrysanthemums are broadly divided into two horticultural groups: garden hardy and exhibition. Garden hardy types are perennials capable of overwintering across most northern latitudes; in theory, C. × morifolium tolerates USDA zones five through nine. These varieties are defined by their ability to produce an abundance of small blooms with little or no mechanical support, enduring wind and rain without staking. Exhibition varieties, by contrast, are generally less hardy and demand staking, overwintering in a cool and relatively dry environment, and sometimes the addition of artificial night lighting to manage their photoperiod-sensitive flowering. Despite their fragility, exhibition types are the canvas for extraordinary artistic training. Growers shape them into large disbudded blooms, spray forms, and a remarkable array of sculptural presentations including thousand-bloom arrangements, standard tree forms, fans, hanging baskets, topiary, bonsai, and cascading displays. The US National Chrysanthemum Society formally recognises thirteen distinct bloom forms, reflecting the extraordinary morphological diversity bred into the species. In American nurseries the plant goes by several common names—florist's daisy, fuji mum, and hardy garden mum—underscoring its dual identity as both a cutting flower and a landscape perennial.