Tagetes sp. or Marigolds, have approximately 30 species in the genus, with strongly scented annual and perennial herbs native from Arizona to Argentina. Leaves are opposite, simple or more often pinnatifid or pinnate and are dotted with glands. Depending on species and cultivar, they can range in height from 1 to 7 feet (30 cm-2.2 m). There are many named cultivars of Tagetes based on flower form, size and color. In the greenhouse, we use them for biological control of spider mites. Once the plant becomes infected, it is removed and destroyed. Although these plants help in keeping mite populations down, they will not completely control the pest. Marigolds are of easy culture and have been used as cut flowers and as bedding plants worldwide. Plants should be treated as annuals.
Blooming Time: Marigolds bloom in the greenhouse all year long. Flowers can be single or double and have a wide range of color depending on species or cultivar. All are very showy.
Culture: Tagetes sp. does best in full sun to light shade with a well-drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part peat moss to 2 parts loam and sand. Plants are well watered and allowed to dry slightly before watering again. We fertilize them weekly with a balanced fertilizer diluted to 1/2 the strength recommended on the label. Since we use these plants in controlling spider mites, we continually have a fresh group of plants. Plants are started at intervals to provide various stages of growth.
Propagation: Tagetes sp. is best propagated from seed.
Tagetes sp. was featured as Plant of the Week January 8-14, 2010.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.