August 11, 2007

Plant of the Week

David Rodriguez

Mari-MumsWow, fall is right around the corner and time for planting the wonderful Mari-Mum is here! This annual is undefeated by far and is considered the best color in the fall for your gardening bucks. Mari-mum is derived from a combination of the terms: marigold and chrysanthemum (fall garden mum) and denotes large-flowered American marigolds. They are hybrids characterized by earlier blooming and possess a similar flower form. They are also used as a fall replacement crop for chrysanthemums. Mari-Mums do extremely well in containers in full sun.

Attributes of the Mari-mum:

  • Are very low maintenance for a flowering annual
  • Are extremely easy to grow (almost foolproof when planted in a well-drained soil in
    full sun)
  • Produce more blossoms and retain better blossom color as a fall crop
  • Possess tremendous visual impact, especially from some afar
  • A earlier blooming with larger flowers and high levels of uniformity

When compared to fall-planted chrysanthemums, Mari-mums:

  • Will bloom two-to-three times longer
  • Their open blossoms are more resistant to wind and rain
  • Are less expensive to produce which gives you more bang for your gardening buck

Spider Mites Not A Problem!
Spider mites, the arch enemy of most marigolds, love hot weather but their rate of reproduction are greatly reduced by cool fall temperatures. By first removing any mite-infested plants from the flowerbed and then by planting fresh marigold transplants in mid-August, you can avoid significant mite injury, all with minimum use of pesticides.

Recommended Cultivars
The super Mari-mum cultivars currently recommended and readily available are the ‘Antiqua Yellow’ and ‘Antiqua Orange,’ dwarf plants 8-10 inches in height.

More about Mari-mum’s
Plant now, in mid August for the longest bloom period. It is VERY IMPORTANT to purchase transplants with foliage only or in bud, but not in full bloom.

Transplants in full bloom at planting devote all of their energy to supporting that tremendous bloom load and thus have little energy left for proper establishment and growth.

  • Plant in full sun (at least 8-10 hours per day).
  • Must have good soil drainage. Incorporate liberal amounts of high grade compost at initial planting with the native soil (about 20% is ideal).
  • Space transplants of ‘Antiqua Yellow’ and ‘Antiqua Orange’ eight inches apart and deeper in the soil, similar to a tomato transplant (only other exception) to the first or second leaf connection. Planting Mari-mum transplants deeper will encourage quicker establishment and greater girth of the main trunk, which will form adventitious roots along the base. This planting depth will later support the tremendous amount of flower weight later in the plants life cycle. Mulch entire bed after planting to reduce water consumption and weed competition. A thin layer of about two inches of cedar or hardwood mulch would be most desirable.
  • Established Mari-mums can be killed by watering too frequently. With the extreme heat of August and often through October, provide adequate and proper amounts of moisture directly to each individual transplant, but do keep a good eye on over watering (minimize the amount of water on the foliage of the plants). Commonly, watering the new transplants once to twice a day for two weeks may be needed. Thereafter, twice a week should be adequate.


Remember, Learn and Have Fun!

David Rodriguez is County Extension Agent-Horticulture, Bexar County. For more information, call the Master Gardener ‘Hotline’ at (210) 467-6575 or visit our County Extension website at, click under Horticulture and Gardening.

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