September 2009

Crop Culture Report: Gerbera Landscape Series By Judy Born

Landscape gerbera is a selection of patio plants selected for their habit, flower size, colors and abundant flowering. The varieties are suitable for outside as well as inside use. The flowers can be cut and placed in a vase for weeks of enjoyment. A duo purpose potted plant with the lady of the house in mind.

A new cultivar in the gerbera species, the Landscape gerbera was bred by Florist de Kwakel and introduced to the market two years ago. This is unique breeding with a cross between a potted gerbera and the cut flower types. They are available only from tissue culture.

Variety Information

The series was originally introduced with seven colors: Everglades (large-flowered pink bicolor), Yellowstone (large-flowered yellow and orange bicolor), Pacific Rim (medium-flowered pink with dark-pink ring), Yosemite (medium-flowered red orange), Mount Rushmore (medium-flowered burgundy), Mammoth Cave (medium-flowered white with dark eye) and Rocky Mountain (medium-flowered peach).

For 2010 there have been five cultivars added with many more in the works. The new colors include : Redwood (medium-flowered red with yellow edging), Kings Canyon (large-flowered yellow with orange bicolor), Bighorn (medium-flowered hot pink), Klondike (medium-flowered double flower golden orange) and Arcadia (large-flowered white). Breeding for uniqueness of flower color and size with a good overall habit, Florist de Kwakel is also looking for stronger plants that will provide the gardener with success.

Crop Information

Landscape gerbera are best planted into large containers — 8 inches being the minimum recommended. Overall crop timing is 14 to 16 weeks from transplant. Do not plant young plants too deep in the substrate. The crown should be visible above the soil line. Plant only one plant per pot, placed in the center of the pot. These plants will grow to be quite large and require the room to develop a good plant. They appear to grow slowly, but once the root system reaches the edge of the pot you will see the plants really start to grow. Plants require spacing when the leaves are touching. Good rule of thumb is to use double spacing.

Fertilization, Water and pH

Landscape varieties are sensitive to water. It is important to make sure that irrigation is applied at the right times (in the morning) and they're dry when the night falls. Grow on the moderately dry side to keep the plants compact. Watering from below is preferable once a root system is established. Landscape gerbera require constant feed with an EC level of 1.5-2.0. It is recommended to obtain a coarse substrate with good drainage. Soil EC should be 1.0-1.2; the pH must be between 5.2-5.8 Higher levels of feed during the vegetative stage of growth is recommended. Watch for yellowing of the leaves or really dark green leaves as this usually is a sign of a pH issue.

Insect and Disease Control

Monitor plants for leaf minor, thrips, aphids and spider mites. Every four weeks a fungicide treatment should be applied along with regular prevention for pests. Mildew prevention is good insurance for producing a premium crop. When the crop is flowering, spray from underneath to avoid damage to the flowers. To prevent Botrytis, provide good air circulation and ventilation to keep relative humidity below 80-85 percent at night. Gerberas also are susceptible to Pythium and Phytophthora.

Light intensity is best around 35,000 foot-candles. Above these figures, screening is recommended. During the wintertime, you can use artificial lighting to maintain the necessary product quality. Approximately 5,500 foot-candles can be added to prolong the day length. Day length should not exceed 16 hours and is ideal at 13 hours.

Temperatures and Flowering

Optimum temperature to grow the best crop is 65-68¡ F. During the last phase or the final four weeks of growth, night temperature can be decreased to 59-61¡ F. Keep your day temperatures at 64-66¡ F. Above 68¡ F, ventilation is needed. Do not drop the night temp below 57¡ F. Keep the humidity below 80 percent. Plants should not be exposed to temperatures above 86¡ F.

In weeks nine and 10 of growth, the first flowers will appear. It is best to pick the first two flowers/buds from the plant to make sure the plant can develop more buds for abundant flowering.

To get a good flush of flowers at one time for optimum sales, keep the plant dry for approximately seven days, then use clear water for the next full irrigation. Plants should be fully in bloom approximately four weeks later. This technique is also useful on regular seed-type gerbera.

Plants are ready for sale when one to three flowers are open with one or two rings of pollen developed. More buds are typically visible and available. You can harvest the crop over three to four weeks. The plants do get better with some age on them with more flowers showing. The only issue at this point is humidity levels in the greenhouse to keep diseases at bay. The plants are continual bloomers, providing good shelf life for the retailer and luxurious cut flowers along with a beautiful plant for the consumer.