Celosias (Celiosa spp.), commonly called cockscomb, feathered amaranth, woolflower and red fox, are warm-weather flowering plants that thrive in hot, humid Mediterranean areas. They are commonly grown as annuals but can survive winters in U.S. Department of Agriculture plant hardiness zones 10 and 11. Mature plant height is generally between 6 inches and 3 feet, depending on the cultivar. Celosias in the “Childsii” and “Cristata” groups have rounded flowers, those in the “Plumosa” group have arrowhead-shaped flowers and those in the “Spicata” group have bottle-brush type flowers. They are all easy to care for as long as their soil and sunlight requirements are met.
Sunlight and Drainage
Celosia plants require a minimum of eight hours of direct sunlight and soil that drains quickly. Poorly draining planting sites can cause them to develop root rot. To test how quickly the soil drains, remove the top and bottom from a large coffee can, dig a 4-inch-deep hole in the soil, the same circumference as the can, and insert the can into the hole. Fill the can with water and check the water level after one hour. If the water level drops between 2 and 5 inches, the drainage is good. When the water level drops less than 2 inches, the drainage is poor. Perlite can be added along with soil amendments to improve the soil's drainage or you can plant celiosa in containers or raised beds.
Organic Matter and pH
Celosias will grow in nutrient-poor, sandy soil but thrive and bloom more profusely in soil that contains high levels of organic matter. Soil pH levels between 6 and 6.5 are best. In fall, before planting Celosia, prepare the planting site by removing weeds and mixing organic matter into the soil. Even sandy loam soil, considered ideal for most annuals, should have organic matter mixed in each year to maintain consistency and fertility levels. Leaf mold, peat, well-aged cow manure and compost are suitable soil amendments. Depending on how much organic matter is already in the soil, spread a 3- to 6-inch layer of soil amendment over the planting site and work it into the soil thoroughly to a depth of 10 to 12 inches. Sulfur may be added to lower the pH and lime can be used to raise the pH.
Planting and Watering
Celosia can be planted in the garden in the spring when temperatures will remain above 60 degrees Fahrenheit. They will be damaged if the temperature drops lower than that. Immediately after planting them, water them generously to settle the soil around the roots. A 3-inch layer of organic mulch can be spread around them to control weeds and help maintain moisture levels. Water them as often as necessary to keep the soil consistently moist.
Fertilizer and Deadheading
Fertilizer may not be necessary. If the plants seem to be growing slowly, apply water-soluble fertilizer with a 3-1-2 ratio every two weeks or use a slow-release granular fertilizer. Tie the flowers on taller cultivars to stakes to keep them from falling over. Remove the flowers as they fade to promote more flowers.
Your Planting Articles
- Missouri Botanical Garden: Celosia Argentea var. Cristata (Cristata Group)
- Missouri Botanical Garden: Celosia Argentea var. Cristata (Plumosa Group)
- Floridata: Celosia spp.
- University of Maryland Cooperative Extension Service: Fact Sheet: Production of Celosia as Cut Flowers
- Clemson Cooperative Extension: Home & Garden Information Center: Growing Annuals
- Mississippi State University: MSU Cares: Coast Gardener: Good Drainage Helps Plants Grow
- Oregon State University: Improving Garden Soils with Organic Matter
- University of Minnesota SULIS: Amending Soils for Perennial Beds
- University of California Cooperative Extension: Changing pH in Soil
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