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Tom Dew
Texas A&M University

July-August, 2002

In 1968, a signature display bed was constructed at the front entrance of the Texas A&M University campus depicting the school’s logo. The logo is a block-style monogram of the school’s initials and is affectionately referred to as the ATM logo.

Alternanthera was chosen for thebed for its vigorous growth, heat tolerance, adaptability to shearing and vivid fall foliage. Alternanthera is in the family Amaranthacae which includes celosia, globe amaranth, gatorweed and pig weed. Tender plant material is available in a variety of colors, hence the common name Joseph’s Coat. Common colors are shades of red, pink, green, yellow and white in variegated forms. Because the flowers are small and invisible from a distance, it is primarily grown for its foliage color. Since conception of the bed, two varieties of Alternanthera have been used. These bronze and green colors are still used today. Bronze is used for the letters, while green occupies the background.

The original plant material has been re-propagated each year. Propagation begins with 2-inch to 3-inch stem tip cuttings. During routine shaping in June, cuttings are taken from the display bed. Only the healthiest and most vivid cuttings are selected. The cuttings are rooted in galvanized pans and use a growing medium of 50/50 Canadian peat moss and Perlite mix. The pans are placed in a greenhouse under a cheese cloth tent to retain a high humid atmosphere. In this environment, the cuttings will form roots. After the roots have developed, cuttings are transplanted, one per container, to 2½-inch rose pots. When fully rooted, three of these plants are stepped up to a 10-inch bulb pot to be grown as stock plants. Stock plants are trimmed as needed to encourage branching and compact growth. A&M gets 50-100 cuttings from each 10-inch stock container.

Starting in late January, cuttings are taken for the bedding plants. Flowers that were formed in the fall must be removed before sticking the cuttings. Cuttings are again placed in rows in pans and shifted one per rose-pot after roots form. If a longer bench life is necessary, a 3-inch to 4-inch pot may be used. While the plants are in the greenhouse, we use Peter’s 20-10-20 water soluble fertilizer.

Before the Alternanthera is planted in the display bed, a granular 13-13-13 fertilizer is tilled in the soil at a rate of 1½ pounds per 100 square feet. A foliar application of 1:2:1 concentrate with a hose end sprayer is used at three- to four-week intervals. We have been using Hasta Grow 6-12-6 water soluble fertilizer by Medina®.

Bamboo stakes and string are used to mark the pattern of our design. Plants are spaced on 12-inch centers. At first shearing, we cut to a height of four to six inches using electric hedge shears. Subsequent shearing is performed at 4-week intervals, with touch up trimming as needed. In September, growth begins to slow, and trimming is required less frequently. This is also when the foliage turns darker in appearance.

We have experienced very few problems with the plant. The main pest problem we have encountered is looper caterpillars, which appear from late summer to early fall. To combat them, we watch for the appearance of small white moths, and apply Dipel when loopers appear.

Another problem is that Alternantera is very sensitive to frost and freezing temperatures. On the rare occasions that temperatures drop low enough to frost, we apply warm water to the leaves beginning between 4 a.m. and 5 a.m. Cold, clear nights pose the greatest risk of frost. With dew on the leaves, frost may occur at temperature as high as 36° F. If the leaves are dry, they may withstand 33° F briefly with little damage.

Alternanthera makes a great plant for living-art sculptures in our region. The challenges are minimal and easy to correct. The plant is gorgeous and low-maintenance. We are proud to be unique in our use of Joseph’s Coat.

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