A Celosia flower plant is an attractive ornamental and can also be an important and versatile leaf vegetable that can be used in all the same ways as spinach. A polytunnel can be the perfect place for celosia growing, though it is also often grown indoors.
Celosia are several species of both ornamental and edible plants in the amaranth plant family. Widely believed to be of African origin, Celosia grow naturally in environments and climates very different to our own and it is mostly found in humid tropical regions.
Many Celosia, however, are cultivated in other regions, including temperate climes, for their ornamental appeal and as a food source.
There are many different varieties of Celosia, generally grouped into two types – one of which produces a cock's comb like flower and the other a feathery plume. Many of the varieties are frost tender, though some are half hardy.
Celosia flower heads appear (depending on the variety) between July and October. These add drama to your garden or to a flower arrangement in your home.
Celosia that is more than just ornamental – it can be harvested as a leafy vegetable crop. The young shoots and leaves can be cooked and eaten and make a pleasant spinach-like vegetable that can be used in many recipes, such as soups and stews. An edible oil can also be obtained from the seed.
Celosia can be grown from seed or you can purchase plants from a garden centre or plant nursery.
Celosia should be potted up into pots of at least 7cm diameter to begin with. In the UK, it is generally necessary to grow Celosia under cover, which means they are best suited for growing in containers which can easily be moved around when the seasons change.
Whether you are potting up home grown seedlings, or a purchased Celosia plant, it is important to choose a container large enough to comfortably accommodate the roots of the plant. These are plants that cannot tolerate being pot bound.
The containers should be placed in a bright, warm and humid location, which mimics as closely as possible the native habitat conditions for this genus.
Before planting in the ground or a raised bed in a polytunnel or greenhouse, amend the soil with organic matter like compost or well-rotted manure to improve its fertility and drainage. Celosia prefers slightly acidic to neutral soil with a pH between 6.0 and 7.0. This is also the optimal ph level if you are selecting a growing medium for plants in pots.
Celosia will need a little TLC in order to grow well in our climate. But a polytunnel can make it easier to give this plant the conditions it requires.
Celosia prefers full sun, so choose a spot in your garden that receives at least 6-8 hours of sunlight per day.
Once seedlings have grown and been potted up, and roots fill the container, water moderately but on a regular basis. Make sure that the soil or potting mix is suitably free-draining and that excess water can drain away freely.
Of course, these tropical plants like it hot. They are not capable of withstanding temperatures lower than 1- 5 degrees C..
Celosia like high humidity, so will do well in a polytunnel with other plants that thrive in a high humidity environment. A daily spraying of the leaves with water throughout the active growing season will help keep the plants at the high humidity that they enjoy.
For best results, apply a good quality, organic liquid fertiliser to your Celosia every couple of weeks over the summer.
Remove spent flowers regularly to encourage continuous blooming throughout the season if desired. Dried flower heads can also be left on the plant and arguably remain an attractive feature.
Celosia is propagated by seed.
Celosia seeds will require a temperature of 18-20 degrees Celsius to germinate so you will need to start them in a warm location indoors or in a heater propagator. The seeds should germinate within a week or so.
When the seedlings are large enough to handle, prick them out and grow on – though still be sure to maintain a temperature of around 16 degrees Celsius.
If the temperatures where your Celosia will be growing will be cooler than this, gradually reduce the temperature and harden off your plants before placing them in their summering growing position.
Interested in extending your enjoyment of celosia flowers into the winter months? You can easily achieve this by drying them! Begin by harvesting the flowers in the morning, once the dew has evaporated. Look for mature blooms that have not yet produced seeds.
Cut the stems to the longest length possible and place them in a bucket of water until you are ready to proceed indoors.
Gather six to eight stems together and secure them with a rubber band. Hang the bundles upside down in a warm, dry location, such as an attic. To retain the vibrant colour of the blooms, it's best to expose them to as little light as possible during the drying process.
Ensure proper air circulation around the bundles to prevent mould formation. With these conditions in place, your celosia flowers should be fully dried and ready for use in approximately a month.
Look to the basic growing requirements. If something goes wrong then it is likely to be due to a problem with temperature, light, humidity or water.
If you are growing your Celosia in containers then it is important never to allow the plants to become pot bound. Always pot up before roots appear out the bottom of a pot. Make sure that drainage holes remain clear and waterlogging cannot occur.
In the United Kingdom, there exists a variety of celosia species, each possessing distinct characteristics and cultivation requirements. Here are some popular selections:
Celosia cristata (Cockscomb): Noted for its unique crested flower heads reminiscent of a rooster's comb, this variety offers a spectrum of vivid colours. Cockscomb celosia is versatile, thriving in both garden beds and containers, provided with ample sunlight and well-drained soil.
Celosia argentea (Plumed Celosia): Plumed celosia showcases elongated, feathery flower spikes, introducing texture and aesthetic appeal to gardens and floral arrangements alike. Available in hues spanning red, orange, yellow, and pink, this variety prefers full sun exposure and moist, well-drained soil conditions.
Celosia spicata (Wheat Celosia): Exhibiting erect, cylindrical flower spikes reminiscent of wheat or barley, this celosia variety delivers a distinctive visual impact. Offering shades of red, orange, and yellow, wheat celosia flourishes in full sun and well-drained soil environments.
' Flamingo feather' is one named cultivar with an Award of Garden Merit from the RHS.
Celosia argentea var. cristata (Cristata Celosia): Characterized by compact, densely clustered flower heads resembling brain coral, cristata celosia presents a diverse array of colors. Ideal for borders, beds, and containers, this variety thrives in locations with full sun exposure and adequate soil drainage.
'Century Rose' is one named cultivar with an Award of Garden Merit from the RHS.
Celosia argentea var. plumosa (Feather Celosia): Featuring elongated, slender flower spikes adorned with petite, brightly coloured blooms, feather celosia exudes an elegant charm. Flourishing in full sun and moist, well-drained soil conditions, this variety offers a captivating presence in garden settings.
'Dragon's Breath' is one named cultivar with an Award of Garden Merit from the RHS.
These selections represent merely a sampling of celosia varieties suitable for cultivation in the UK.
Celosia can be enhanced by a diverse array of companion plants that elevate its colours, textures, and overall garden appeal. Here are some noteworthy companions for celosia:
Marigolds (Tagetes spp.): Renowned for their vibrant hues and natural pest-repelling properties, marigolds offer a striking contrast to celosia blooms while assisting in pest management.
Zinnias (Zinnia spp.): With their wide range of colors and varied bloom shapes, zinnias complement celosia beautifully, thriving in similar growing conditions and enriching garden beds with visual allure.
Salvia (Salvia spp.): Available in diverse heights and colors, salvias serve as an elegant backdrop for celosia, their spiky flowers providing an appealing contrast to celosia's plume-like blossoms.
Cosmos (Cosmos bipinnatus): These easily cultivated annuals present delicate, daisy-like flowers, imparting a soft, airy ambiance to garden borders and offering a harmonious blend of hues alongside celosia.
Nasturtiums (Tropaeolum majus): With their vibrant, edible flowers in shades of red, orange, and yellow, nasturtiums inject a cheerful pop of color into garden landscapes, attracting beneficial insects to aid in pollination.
When selecting companion plants for celosia, consider factors such as sunlight, soil preferences, and height compatibility to curate a harmonious garden display that maximizes visual impact and biodiversity.
Each of the plants mentioned above can also be good companion plants for other crops in a polytunnel – serving a practical purpose in attracting pollinators etc. as well as looking good.
You might also grow Celosia alongside other amaranths with edible yields, such as Amaranthus ssp. or quinoa, for example.
Keep an eye out for common pests like aphids, spider mites, and caterpillars, as well as diseases like powdery mildew.
On the whole, however, problems are most likely to arise due to something lacking in the environmental conditions or care. Chill temperatures, low humidity, and too much water/ waterlogging are among the main things to look out for and avoid.
In a sunny and humid polytunnel, Celosia should thrive over the summer months, as long as you water consistently but not excessively and maintain humidity, and otherwise care for the plants as described above.
Celosia may seem like an unusual polytunnel plant, but as an ornamental or as a crop, they are great value, and not all that challenging to grow as long as you keep the basics in mind.
Lastoe, S., (2021) Cockscomb Is the Green You Should Be Eating. Food & Wine. [online] Available at: https://www.foodandwine.com/lifestyle/cockscomb-green-you-should-be-eating [accessed 20/03/24]
