Mum, Chrysanthemum, or Hardy Mum

(Asteraceae [also known as Compositae] - Daisy Family)

Form
• medium-sized herbaceous annual or small half-hardy herbaceous perennial (depending upon hardiness zone, overwintering, soil drainage conditions, and plant genetics)
• maturing at 1' to 2' tall by 1' to 2' wide, depending upon cultivar as well as Summer cultural shearing
• radiating clump growth habit

Culture

• full sun to partial shade
• prefers a moist, rich, well-drained soil in full sun, with supplemental fertilizer added at transplanting, but is often planted as a late-season, root-bound annual from containers and put into fairly dry soils of average fertility, with minimal root pruning, mulching, and follow-up irrigation
• cultivars that are true annuals and that are sold in late Summer and early Autumn are propagated by rooted stem cuttings, but true perennial forms are propagated by either rooted stem cuttings or crown division
• Daisy Family, with several relatively minor diseases (including crown rot) and pests (including spider mites, aphids, and stalk borers) when sited to the landscape
• abundantly available in containers, usually from mid-Summer to early Autumn when they are sold as functional annuals for Autumn color
• for Mums that are true hardy perennials for a given hardiness zone, the early stems are often sheared back in late Spring to create a compact, dense, rounded form, and the early floral buds that appear during Summer should be pinched back about two to three times (but not after July 20) to promote larger early Autumn flowers
• most modern Mums are not bred for Winter hardiness; those that are desired to be perennials in the landscape need to have a rich soil (for nutrients and quick root establishment) that is well-drained (to prevent future crown rot), with roots sliced to promote outward root growth after being pot-bound (girdling roots), and need to have a light covering of Winter mulch or evergreen boughs in place by late November to protect the crown

Foliage

• medium to dark green foliage is thick and lush, to 3" long, alternate, short-petioled, and arising from grooved stems, with three to five rounded lobes, with each lobe being deeply crenate
• fall color continues as a medium to dark green, serving as an effective contrast below the brightly colored floral display

Flowers

• the ray flowers are found in many shades of solid yellow, amber, orange, or red (warm colors), lavender or violet (cool colors), and white, or in bicolors
• if double-flowering, the ray flowers extend to the center, but if single-flowering, the disk flowers in the center are yellow; overall, the showy dense inflorescences range from 1" to 4" across
• flowers emerge from silvery-green large terminal floral buds, with a two- to six-week display of vivid color in September and October (bloom can sometimes be extended into November if plants are continuously dead-headed and protected from frosts)

Fruits

• ornamentally insignificant, if fruiting occurs at all before frost; deadheading of true perennial Mums is recommended if blooms are sporadic over a long period (due to a lack of Summer floral bud pinching) instead of emerging all at once (as in commercially sold cultivars for Autumn planting)

Twigs

• not applicable

Trunk

• not applicable

ID Summary

• lush green, deeply sinuate foliage is crenate, alternate, and originating from ribbed green stems; however, these features are virtually ignored, as this annual or half-hardy perennial is grown for its spectacular floral display, of either single or double profuse flowers that adorn the top of the plant in late Summer and early to mid-Autumn, in a wide array of predominantly solid colors (or solid-colored "petals" with a central yellow disk)

Function

• primarily an Autumn color accent and often used to replace spent Summer annuals, commonly used at edgings, foundations, entranceways, mass plantings, raised planters, and in large pots
• can be used as a cut flower, especially from taller cultivars that have long stems

Texture

• bold texture
• thick density, especially if culturally sheared and pinched

Assets

• spectacular floral display in late Summer or early- to mid-Autumn
• lush, dark green, dense foliage
• usually transplanted when in full floral bud or full flower to yield an instant splash of vibrant color in the Autumn landscape

Liabilities

• unlike the common name of Hardy Mum, modern cultivars are not cold-hardy in many Northern climates, and are often a short-lived perennial in Southern climates; for this reason, most Mums (and also ornamental Cabbage and Kale [Brassica oleracea cultivars]) are treated as functional annuals in the Autumn landscape
• as most Mums are grown in very porous, soilless media, they have a tendency to easily dry out and wilt, unless supplemental irrigation is regularly applied

Habitat

• zones 5 to 6 as a functional annual (where it will die out in most Winters unless it is planted in a rich, well-drained soil and adequately mulched); zones 7 to 9 as a potential true perennial
• native to the Orient; modern cultivars are of complex hybrid origin

SELECTIONS

Alternates

• Autumn-flowering or Autumn foliage-coloring herbaceous plants, that are annuals or half-hardy perennials (Brassica oleracea, Viola x wittrockiana) or perennials (Aster, Boltonia asteroides, Eupatorium, Sedum 'Autumn Joy', Solidago, etc.)

Variants

• many new selections are introduced and many old selections are discarded every year, usually bred for compactness, floral color, floral size, and floral type (see below), but usually not bred for Winter hardiness
• Daisy Type - single-flowering, with a ring of ray flowers ("petals") surrounding the yellow disk flowers ("eye" or "center") of each inflorescence
• Decorative Type - double flowering, with many ray flowers in a relatively flat arrangement across the entire inflorescence
• Pom-Pom Type - similar to the Decorative Type, except that the entire inflorescence is globular and often large
• Quilled Type - double flowering, with the ray flowers being thin, linear, and semi-pendulous

NOTES

Translation

• Dendranthema is of uncertain meaning, but literally translates as "tree anther" or "tree flower".
• x grandiflora translates as "grand flowering", referring to the showy floral display.
• formerly known as Chrysanthemum x morifolium, with Chrysanthemum translating as "golden flower", referring to the fact that many older varieties and species of Mums have earth-tone floral colors, and with morifolium translating as "Mulberry foliaged", referring to the resemblance of the leaf shape of Mums to the lobed leaves of Mulberry (Morus species).

Purpose

• Mum is an Autumn accent herbaceous plant noted for its bright showy flowers.

Summary

• Dendranthema x grandiflora is a functional replacement annual in Northern climates or a half-hardy perennial in Southern climates, noted for its fall-blooming accent display of dense showy floral heads above lush green foliage.