Mums the Word

The genus Chrysanthemum used to comprise over 200 species, including the fall-blooming plants we commonly refer to as chrysanthemums or mums. In the late 1990s, after much work, taxonomists split the genus up into many groups, putting those common mums into the genus Dendranthema. Other popular garden plants were placed in different genera: marguerite daisies became Argyranthemum; Chrysanthemum pacificum became Ajania; the wild ox-eye daisy is now Leucanthemum; Montauk daisy is Nipponanthemum; and tansy and feverfew are now Tanacetum. However, after much discussion, it was decided to conserve the name Chrysanthemum for all those fall-blooming "mums," since the name was so widely used. As a result, they are now properly Chrysanthemum once again.

Adding to the confusion, Korean mums, which flower so beautifully in the Home Gardening Center, were hybridized in Connecticut in the 1930s. A nurseryman, Alex Cummings, was working on hybridizing cold hardy varieties that would flourish in New England temperatures. A tall plant — a wild species he mistakenly identified as Chrysanthemum coreanum — fell into his hands and the results were the lavish Korean mums you see today. The plant turned out to be Chrysanthemum sibiricum, a wild mum with white-pink daisies, vigorous growth, and good branching. This species is also native to Korea, so the popular name Korean mums is correct. Korean hybrids tend to be four feet tall with spectacular daisy-like flowers that come in a wide range of colors from pale yellow and dusty pink to burnt orange.

Chrysanthemum rubellum is another group of hardy chrysanthemums. They tend to reach 2-3 feet in height, spread to form open and loose clumps, which often require staking, and are hardy to zone 4. They are sturdy creatures and easy to grow. If you would like to avoid staking them in September and October, try pinching them back by half in June. Many of the popular rubellums are Chrysanthemum 'Clara Curtis', Chrysanthemum 'Mary Stoker' and Chrysanthemum 'Duchess of Edinburgh'.

Although the classic Chrysanthemum 'Sheffield Pink', also known as 'Hillside Sheffield Pink' or just 'Sheffield', is generally classified as a rubellum, it is sometimes classified as a Korean hybrid. Either way, it is worth growing in your late-season perennial border matched with the burgundy-leaved Sedum 'Matrona' or a wispy ornamental grass.

The chrysanthemums that are widely available in the fall tend to be annuals. They are dwarf varieties that have been hybridized for compact growth and plenty of flowers. A few of them may be hardy, but most will not survive the winter. They offer an easy, inexpensive way to add color to your fall garden. Use them in containers or mass them along walks or in flower borders where you can enjoy their cheerful colors.

Basic Chrysanthemum Care:
* Mums like full sun to partial shade. If you are planting annual mums, they will tolerate more shade, since they have been grown-on in the sun and can flower in lower light conditions. Too much shade will cause their leaves to yellow.
* Plant hardy mums in May or June for best results. Alternatively, plant until the end of September, leaving them at least 6 weeks to allow their roots to establish before a heavy frost. Water well until the roots are established.
* Add plenty of organic matter to your soil: compost, decomposed leaves, or peat moss are all good alternatives. Mums like rich, well-drained soil.
* Make sure that you do not plant your mums near a street light or a light source during the night-they need the longer nights to tell them it is time to flower.
* Mulch your mums in the fall if they are recently planted.
* Do not cut your mums back until spring. The stems will trap snow and give added winter protection by insulating the crown of the plant.
* Pinch mums in late May or June when the shoots are 6 inches tall to encourage branching and a nice bushy appearance. Pinch again when the shoots are between 3-6 inches tall. Continue pinching until July 4th. For the simple version, wait until the middle of June and then cut the plant back by half-cutting just above a leaf node (where the leaves join the stem). Not only will the mum fill out, it will reduce in height, lessening the probability of staking in the fall.
* Mums should be divided in the spring, just when new growth is starting to appear. Discard the dying center, and keep the vigorous shoots on the outside of the plant.
* Alternatively, to propagate your mums, take cuttings in the spring (cut just below the leaf node). Cuttings can be rooted in sterile potting soil; keep watered and place on a sunny windowsill.


The chrysanthemum, or kiku in Japanese, has been the national flower of Japan for a thousand years. Over the centuries, Japanese gardeners developed many different styles for growing and training chrysanthemums for autumn celebrations. Flowing cascades and tall columns of mums, inspired by Japanese gardens, are one of the specialties of The New York Botanical Garden. For 11 months, these mums are pinched, trained, and tied to frames to produce the beautiful floral displays can be seen in the Momijigari exhibition — a celebration of fall in Japan — in the courtyard of the Enid A. Haupt Conservatory.

Season: Fall