Gerbera or Transvaal daisy (Gerbera jamesonii) is native to Transvaal, South Africa and is a member of the sunflower (Asteraceae) family that includes chrysanthemums, marigolds, and zinnias. Gerberas are popular plants for the garden, and their daisy-like blooms make long-lasting cut flowers. They tolerate temperatures down to 30°F although they will be damaged by frost. In central and south Florida, Gerbera daisies perform as perennials, but they should be treated as an annual wherever prolonged freezes are likely.
Each flower is held about 6- to 12-inches above the foliage on a long, leafless stem. The leaves are long, slender and hairy (pubescent). Plants form dense, 12-inch-tall clumps of numerous leaves.
Flower Colors and Forms
Gerbera flowers measure 2 to 5 inches across and can be white, or shades of yellow, orange, pink or red. The center (eye) of the flower can be green, brown, black or dark red. There are five distinct flower forms based primarily on the rows of petals and how they overlap: single, double or duplex, crested doubles, full crested doubles and quilled crested doubles. Plants are sold in spring in north Florida and are usually available year-round in central and south Florida. Most are sold in bloom, which makes color and flower type selection easy.
Planting and Care
Gerberas grow best in well-drained, sandy soils amended with organic matter. One to two inches of peat, compost or other organic material can be incorporated into the soil before planting. Excessive moisture during the rainy season may increase the incidence of root disease. Where drainage is a problem, grow gerberas in raised beds, mounds or containers.
Water the plants well before you remove them from the pot. Gently remove the plant from the pot and examine the roots. Carefully untangle them and loosen the root ball if they appear "pot bound."
Space the plants 12 to 18 inches apart, being careful to plant the crown at or slightly above soil level. The crown should be visible after watering. While gerberas like regular moisture, the crown should be allowed to dry out between irrigations. Mulch with 1 to 2 inches of organic material, taking care, once again, not to bury or crowd the crown.
Gerbera crowns gradually sink into the soil after a period of growth. The crown becomes entirely submerged after a year or two, and excess moisture at this time often induces crown rot, causing the plant to die. To prevent crown rot dig, lift and replant the gerbera every two years.
Gerberas respond to high fertility levels and should be fertilized regularly. Apply a controlled-release fertilizer 2–3 times during the growing season or use a complete fertilizer once a month. Select a fertilizer that contains iron or manganese because gerberas are prone to deficiencies of these micronutrients. You can also correct these problems with foliar sprays of products containing micronutrients.
Gerberas can be grown in full sun but perform better with morning sun and afternoon shade. Remove spent blooms and old leaves regularly to avoid disease.
The most inexpensive way to produce gerberas is from seed. However, plants propagated from seed are usually not true-to-type and may vary greatly in flower color.
Germinate seed in a sterile, lightweight medium such as vermiculite, perlite or ground sphagnum. Place the medium in pots or flats that have drainage holes. Make shallow rows in the medium approximately twice as deep as the diameter of the seed. Sow seeds in the rows, cover lightly with extra medium and water carefully. Cover the container with a sheet of glass or clear plastic and place the germination container in bright, indirect light or approximately 18 inches below a fluorescent light. Frequently check the soil moisture and do not allow it to dry out. Transplant seedlings to small pots as soon as the first true leaves appear. Seedlings can be grown in small pots until they are large enough to transplant into flower beds.
Gerberas with multiple crowns can be dug and divided at any time of year in south Florida and during spring and summer in north and central Florida. Separate the crowns using a clean sharp knife or pruning shears. Remove dead roots, old decaying leaves and one half of all the lower, mature leaves and replant immediately. Keep the transplants moist until they are re-established.
Pests and Diseases
Gerberas are occassionally attacked by leaf miner insects. Tiny flies deposit eggs on the leaves. These hatch and the larvae feed on the leaf tissue, producing tunnels that appear as squiggly lines. This is generally a minor problem. Remove badly damaged leaves, and if desired, use a systemic insecticide.
Caterpillars and cutworms can also be destructive. Plants attacked by these pests have ragged leaves or they may suddenly wilt and die if the stems have been damaged. Hand picking is the most effective means of control.
Spider mites and thrips may be problematic. Both pests feed on plant juices and often go undetected because of their tiny size. Thrips attack flowers and leaves; spider mites usually damage new growth first. Infestations of mites are most severe during warm dry weather. If a pesticide becomes necessary, be sure to thoroughly spray the entire plant including the underside of the leaves.
Powdery mildew diseases occur during periods of high humidity (80%–90%) and moderate temperatures (68°F–82°F). Shade and overcrowding can also favor development of these fungal diseases. Small patches of white mildew form on leaves and flowers and spread quickly. Affected plant parts dry up and die https://edis.ifas.ufl.edu/pp257. Your local UF/IFAS Extension office can recommend effective products and strategies for managing these problems: http://solutionsforyourlife.ufl.edu/map/.
Two fungal diseases which sometimes affect gerberas are powdery mildew and gray mold. Gray mold is caused by the fungus Botrytis cinerea, which attacks dead plant parts, and, when conditions are favorable, spreads to living leaf and flower tissue. Remove dead or spent flowers and leaves to remove the source of infection.