Updated: October 10, 2022
By Stanton Gill , and Ethel Dutky

Introduction

Celosia is one of the most versatile herbaceous plant genera for cut-flower production. Flower heads may be harvested for fresh sales or dried for sale as everlasting flowers or use in potpourri. Inflorescence shapes range from enlarged spikes to fasciated, crested, and convoluted combs. Celosias are separated into three major groups: plume type, Celosia plumosa; crested type, C. cristata; and wheat type, C. spicata, which resembles a wheat head. Celosia flowers come in many shades of red, purple, gold, orange, and yellow, including multicolored flower heads. The name Celosia is derived from the Greek word 'kelos', meaning burn, which describes the flame-like colors and inflorescence of some cultivars. Celosia thrives in hot, droughty conditions and generally performs poorly in cool, wet summers.

Plume type celosia
Plume type celosia flower
Crested type celosia
Crested type celosia flower
Wheat type celosia
Wheat type celosia flower

Propagation

Celosia is propagated from seed (43,000 seeds/ounce). Many cut-flower growers collect seed for future production. Some crested- and wheat-type varieties will reliably give back the characteristics of the parent plants when grown from seed, but many plume types will produce unpredictable shapes and colors.

Celosia seed is extremely small, and seedlings are vulnerable to damping-off. Celosia grows best when started in market packs or in trays in a greenhouse. However, Celosia seedling roots are sensitive to transplanting. If you start seeds indoors, plant them in individual cells or pots, not in flats. Sow Celosia 4 weeks before the last frost date. Seed does not require light to germinate but must be lighted shortly after germinating to prevent plant stretching.

Care is needed to keep Celosia seed from drying out. Lightly cover seed and place it under mist for 10 to 14 days until it germinates. Germinate Celosia seed at 65 to 70 °F at night and at 80 to 85 °F during the day. Exposure to temperatures below 60 °F will stunt plants and cause premature flowering.

Some growers plant Celosia directly into prepared field beds. Sow or transplant Celosia in the field after the danger of frost has passed. In general, field­ planted Celosia seed and weed seed germinate at the same time and create an undesirable, competitive environment. A plant started in the greenhouse and transplanted to the field has a head start in competing with weeds.

Transplanting

Transplant Celosia to the field when night (field) temperatures are consistently above 65 to 70 °F and plants are in the 2- to-4-leaf stage, approximately 4 weeks after sowing. Do not hold plants in mar­ket packs or other growing containers. Once seedlings are potbound, they have been stunted and will never develop into full-sized plants. If they have been severely stunted, celosias will bloom prematurely with small flower heads and short stems. After transplanting seedlings, make sure they receive one inch of water each week from either irrigation on rain. Although Celosia is heat and drought tolerant, lack of steady moisture can stunt plants and promote premature flowering.

Spacing in the field depends on the type selected and whether single-stem or pinched-production is the management choice. Crested types need at least 18 inches between plant centers. Plume types should have at least 24 inches between plants. Wheat types should be planted 24 to 36 inches apart. Spacing can also affect the final flower size. Spacing on 6-inch centers is necessary to produce plants with small heads, which may be desirable in some markets.

Newly planted celosia plugs into plastic in field
Newly planted celosia plugs into back plastic in the field.
Cut flower celosia production in a greenhouse
Cut flower celosia production in a greenhouse.

Field Production

Celosia thrives in well-drained soil with a pH of 6.0 to 6.4. For cut flower field production, pick a location with a rich, deep, loamy soil and at least 8 hours of sunlight. Plants with too little sun will be leggy and will not produce marketable flowers. Celosia normally requires 4 to 12 weeks of vegetative growth prior to flower initiation for optimum shoot development.

To obtain the maximum number of multiple flower heads for crested- and plume-type Celosias, pinch plants 2 weeks after transplanting. This will promote branching and multiple, small flower heads. If you have a market for large, crested Celosia flower heads, do not pinch the first bloom. Some of the crested types may require staking to keep flower heads from falling over. Wheat­ and many plume-type celosias are free branching and do not require pinching.

Celosia plants need relatively high amounts of nutrients; nitrogen is the key element. Select fertilizers with a 3-1-2 ratio of nutrients. Run a soil test and bring up fertility levels according to Maryland nutrient management regulations before planting Celosia. After planting, maintain high fertility levels to promote growth.

Greenhouse Production

Celosia can be produced in green­ houses from spring through summer. The vegetative growth of greenhouse Celosia benefits from high humidity and 3,500 to 5,000-foot candles of light. For plant approaching harvest, shade and less humidity improve the postharvest quality.

Nutrition: Greenhouse Celosia needs weekly applications of a dilute complete fertilizer (for example, 20-10-20 or 15-5-15) at 100 to 150 ppm based on nitrogen.

Temperature: Once Celosia plants are established, warm temperatures (80 °F) will promote flowering better than cool temperatures (below 50 °F). Because Celosia exhibits a strong response to temperature, sequential plantings can extend the period of harvest.

Photoperiod: Celosia is a quantitative short-day plant. Although it will flower at any photoperiod, one of 14 hours or less is best. For the fastest flowering, 4 to 5 weeks of short days are needed. After 4 weeks, there is no delay in the rate of flowering or reduction in flower quality if Celosia receives a long-day photoperiod. Long days promote increased fasciation in crested types.

Aphids

Celosia is unaffected by most insect pests, however, green peach aphid, Myzus persicae, and melon aphid, Aphis gossypii, occasionally do some damage. Heavy aphid populations can cause stunting and deformed flower heads. Look for these pests clustered on the growing tips of plants.

Biological Control of Aphids
Aphid populations can be controlled by naturally occurring parasites and predators. Many of these beneficial insects are attracted by flowers. Growers can help preserve beneficial insects by avoiding cover sprays of residual insecticides. If aphid populations reach plant-damaging levels in spite of beneficial insects, spot treat with short residual chemical.

The lacewing (primarily genera Chrysopa and Hemerobius) is a common aphid predator and can be purchased from biological control companies. Check new growth for aphids. If they are discovered, release lacewings at the rate of 1 predator to 50 aphids. To be effective, lacewings must be released before aphid populations reach damaging levels.

Chemical Control of Aphids
Horticultural oils, insecticidal soaps, and neem are three biorational chemicals that suppress aphid populations. Biorational chemicals are materials that have short residuals and minimal impact on beneficial insects and nontarget organisms. Because these chemicals have no long-term residual effects, regular monitoring of aphid populations is recommended and repeat applications of the chemicals may be necessary. The systemic insecticide Altus is labeled for use on herbaceous plants and effectively controls aphids. Once a systemic insecticide has dried and been absorbed by the plant, the effect on beneficial insects is minimal.

Heavy infesation of aphids on celosia
Heavy aphid infestation with many cast aphid skins on celosia.
Cardboard shipping cells for lacewing larvae
Lacewing larvae can be used for aphid control. Lacewing larvae come in corrugated packaging with individual larvae placed in their own cell and covered with a mesh material to deter them from feeding on each other in transit.

Diseases and Other Problems on Celosia

Diseases
Few diseases affect Celosia. Most diseases that pose a threat can be prevented by good sanitation practices. In the field, this means destroying old plants; in the greenhouse, good sanitation includes dis­ infecting growing surfaces and using sterilized soil media and clean water sources.

Fungi
Celosia seedlings are susceptible to damping-off caused by Rhizoctonia, Pythium, and Phytophthora fungi. Disinfecting growing surfaces and maintaining strict sanitation are the most important practices to prevent damping-off. 

Leaf spot, caused by the fungi Altemaria, Cercospora, and Phyllosticta, is occasionally a problem for Celosia. Overhead watering promotes leaf spot, thus, trickle irrigation is recommended for field-grown Celosia. If overhead watering is the only method available, water early in the day so that foliage will dry completely before nightfall.

Nematodes
The root-knot nematode, Meloidogyne spp., can attack and damage Celosia. The nematodes feed inside roots and produce visible swellings. Celosia infected by root-knot nematodes are stunted, off­ color, wilt in hot weather, decline, and die. New field production areas should be tested for nematodes before planting. If plants begin to perform poorly, inspect their roots for swellings. If swellings are visible, destroy the infected plants and treat the fields for use the following year. Chemical nematicides are toxic to plants and should be applied only to fallow ground. Thus, control of plant parasitic nematodes must be done prior to planting.

Ozone
Celosia is sensitive to ozone, an air pollutant that can injure plants. Ozone can reach high levels in Maryland; the highest levels occur when it is sunny and hot. Ozone enters leaves and dam­ ages the internal leaf cells when stomates are open. The first symptom of injury from ozone is a fine stipple or flecking on the upper surface of leaves. Irrigation causes leaf stomates to open, therefore, growers should avoid irrigating during the hottest part of the day (10 a.m. to 2 p.m.) when high ozone conditions exist. Schedule watering from sunrise to midmorning.

Season of Bloom: Celosia blooms from midsummer to fall and produces harvestable flowers for up to 8 weeks. Sequential planting (every 2 to 4 weeks) of crested or plume types will ensure a constant supply of large flower spikes.

Harvesting: Harvest crested Celosia when the center of the head has expanded but before outer edges begin to discolor. Plume- and wheat-type celosias should be harvested when 50 percent of their flowers are open. Late harvest of flower heads will allow the development of seed that will shatter in the consumer's environment. Cut Celosia so that two or three leaves remain on the stem. The leaves help pull water up the stem, which helps retain freshness. Secondary flowers can be used for potpourri or crafts.

Drying Celosia for Everlasting Sales: Crested- and plume-type celosias are well suited to drying and selling as ever­ lasting cut flowers. Wheat-type Celosia has a tendency to shatter when dried, making it difficult to handle or ship without damaging the flower head. The wheat Celosia 'Flamingo Feather' dries to a snowy white. 'Flamingo Purple' and 'Tassles Deep Rose' retain their color fairly well when dried.

For the best color retention, all celosias should be dried rapidly. Some growers utilize a greenhouse covered with black plastic, place harvested stems on a bench, and use exhaust fans to carry out moisture. This is done for 7 to 14 days.

Summary

•           Select Celosia types and colors according to your market needs.
•           When starting seedlings in containers, keep the plants growing vigorously. Do not allow the  
             plants to become stressed because this may cause premature flowering.
•           Grow plants in full sun.
•           If you desire multiple flower heads, pinch plume and crested types when the first flower forms.
•           Monitor for aphids and beneficial insects.
•           Monitor for diseased plants and promptly remove those that are infected.

References and Disclaimer

References

Armitage, Allan M. 1993. Specialty Cut Flowers. Athens, GA: Varsity Press, Inc.
Nau, James. 1993.  "Culture Guide."  In the Encyclopedia of Seed Germination. 2nd ed. Batavia, IL: Ball Publishing.
Seals, Joseph. 1993. Cut Flowers-Prolonging Freshness. Batavia, IL: Ball

*Disclaimer
Use of brand names does not express or imply an endorsement by the University of Maryland, College Park College of Agriculture and Natural Resources or Maryland Extension.