Learn to Grow Carnations
as a cut flower crop
- in a greenhouse or in the field
- using hydroponics, in pots, or in soil.
This course is relevant to growing any of the Dianthus cultivars. It will have the greatest relevance to growing carnations; because they are the most significant type of Dianthus in cultivation.
Carnations are grown widely around the world as a cut flower crop, a bedding plant and in other ways as a decorative plant (eg. As a pot plant)
Related Dianthus species and cultivars are widely grown as ornamental flowers, both being treated as annuals, and as perennials; as bedding plants, container plants and rockery plants. This course can be every bit as relevant to these situations as to growing cult flowers..
What are Carnations?
Carnations are plants bred and selected from clove scented species of Dianthus. The original development started in the 19th century. In 1903 a breeder (Mr H. Burnett, Guernsey) developed a perpetual flowering carnation as a hybrid. The development of other hybrids followed rapidly.
There are two main types grown as cut flowers are ‘Standard’ and ‘Spray’.
Standards have the side buds removed, to produce a long stem with one terminal flower. Most standards grown are bred from an American cultivar called "William Sim"
Sprays are not disbudded. They are grown with many flowers branching from a stem, and are sold as a bunch.
Description of Selected Species
Commonly known as “Sweet William” - this is an annual, short lived but with spectacular and diverse flowering.
Foliage is nearly glaborous, leaves have a short petiole, leaves are lanceolate with a pronounced mid rib; growing up to 70cm tall (many cultivars much shorter though), Cymes (flower heads are relatively flat topped, flowers often doubles (ie. double row of petals, with inside row bearded),
Sometimes called “Carnation”; strongly perfumed with a clove scent, this is a parent of many of the modern “carnations”.
Relatively upright growth habit (may need support) 35cm to 1m tall; foliage is glaucous (blue green), leaves are 7 to 15 cm long; flowers relatively large (perhaps 2 to 8cm diameter, commonly 2 to 5 flowers on a flower head.
One of the best known species, commonly known as Cheddar Pink (It was discovered on slopes near Cheddar in England.)
Blue-green linear to lanceolate shaped narrow leaves, stems growing around 6 to 20cm long
Flowers are rosy pink, occurring singly or in small numbers, petals are bearded, toothed
Strongly clove scented; sometimes called Cottage Pink.
A spreading - mat forming plant sometimes to around 30cm tall; Leaves are very narrow, glabrous and glaucous. Usually one to three flowers in a flower head; calyx to around 2.5cm long, petals often purplish fringed with a different colour.
Review of the system of plant identification
Methods of propagating this group of plants
Propagation of selected varieties
Pest and Disease
Harvest, Post Harvest and Quality
WHERE CAN YOU GROW DIANTHUS?
The ideal growing requirements can vary from one species and cultivar to the next.
- Most do best in a mild temperate climate.
- Some can be cultivated in sub-tropical regions; at least during certain times of the year.
- Many will tolerate periods of extreme cold
Most plants will survive below freezing. Some species tolerate much lower temperatures than others, for example:
- Perpetual flowering cultivars, commonly grown as cut flowers are best grown at temperatures between 12 degrees C at night and 19 degrees C in the day. Temperatures below 2 degrees Celsius can cause damage to flowers. Day temperatures over 21 degrees C can reduce flowering; and increasing temperature and humidity can cause disease and pest problems. .Aim for temperatures no lower than 7 celsius in winter, if possible.
- Malmaison carnations –over winter temperatures to 2 degrees C
- Dianthus barbatus (Sweet William) can survive temperatures below zero degrees Celsius
- Dianthus gratianopolitanus can tolerate temperatures many degrees under zero Celsius.
- Dianthus chinensis can tolerate to between minus 12 and minus 17 degrees Celsius, depending on the cultivar)
Flowering of carnations can decrease at temperatures over 21 or below 10 degrees celsius.
Long days will stimulate formation of flower buds; and short days will significantly slow (but not stop) the formation of flowers. Low light intensity will also greatly reduce the development of flowers
- Artificial lighting can be used in winter to stimulate a flower crop; provided night temperatures are maintained at 10 to 12 degrees C
- Some cultivars do not respond to artificial lighting as well as others.
- Artificial lighting involves applying a long day length for 2 to 3 weeks followed by short day lengths for 2 to 3 weeks. Sometimes a second period (2-3 weeks) of long days is then applied. Combined with minimum night temperatures of 10 to 12 degrees C, this can stimulate significant out of season flower production on appropriate cultivars. Carnations should have shoots at least 15cm long before commencing artificial lighting.
- Excessively long periods of light can result in too much growth going into flowers, and not enough into foliage; and this can cause a subsequent decrease in flower production later on. It is all about balancing the flowering with the vegetative growth.
- Malmaison Carnations may need shading from sun in mid summer.
AFTER YOUR STUDIES
Business or Employment Opportunities may include
- Cut Flower Production
- Flower marketing
- Seed Production
- Nursery Plant Production
- Herbs –eg. Dianthus production for perfumery oils, medicinal, culinary, or craft use