Pot and bedding - Rudbeckia hirta

New Entry 2009
Rudbeckia hirta
"Denver Daisy"
Flowering period: April - November

Height 25 - 50 cm
Spread: 25 - 50 cm
Habit: Upright
Flower type: Simple
Leaf Color Light Green
Placement: Full sun to partial shade
Water Medium to low
Fertilizer need: Average
Plant type: Annual

Class New Entry 2009

RUDBECKIA HIRTA, CONE FLOWER 'Denver Daisy'

Rudbeckia 'Denver Daisy' was selected for the city-wide beautification on the occasion of the 150th anniversary of the city of Denver (Colorado) because of its extreme heat tolerance, its summer-long flower power, and its ability to stand up under extreme weather variations. Growers will love this new Rudbeckia because of its high germination rates and high percentage of usable seedlings. Low cultural inputs and short crop times ensure that the new 'Denver Daisy' will perform in a wide array of greenhouse situations. Flower power is no understatement for this beauty as large masses of golden flowers adorned with rusty red rings cover the 'Denver Daisy' from late spring until first frost. Strong, dense flower stems (45-50 cm tall) 18-20'' ensure that the 'Denver Daisy' will not flop or fall over in adverse weather conditions.

TECHNICAL INFORMATION

Crop Time:   Plug crop: 5-6 weeks; Flowering pots: spring: 14-16 weeks, summer: 12-14 weeks

Seed Form:   Coated Seed

Seed Count:   0 K/g

Sowing Time:   January for flowering in pots from April onwards; April for flowering in pots from June onwards

Sowing Method:   2-3 seeds per plug, can be sown directly into final pot

Germination:   Stage I and II: 14-21 days at 20-22 °C 68-72 °F; Stage III and IV: 10-14 days at 18-20 °C 64-68 °F, in media with very low soluble salt levels and pH: 5.8-6.2. Before sowing treat substrate with fungicide. Cover seed lightly with vermiculite after sowing. Keep soil slightly moist but not wet. Avoid direct sunlight by shading seeds after sowing

Growing On:   5-6 weeks after sowing transplant 1-3 plants into a pot, 10-17 cm 6'', or into a container (3-5 l). Plant cut flowers (frost free) in 25-30 x 30-35 cm space.

Media:   Use a well-drained, growing substrate with 20-30 % clay, 1-1.5 kg/m³ complete balanced fertilizer, 0-2 kg/m³ slow release fertilizer (3-6 months), ironchelate, micronutrients, pH: 5.8-6.2. Field: loamy sandy to sandy humus soils with good drainage and good nutrition levels. Standard fertilization: 80-100 g/m² of a slow release fertilizer.

Photoperiod / Light:   Long day plant. For flower initiation long day (14-16 h) is required. Keep light level high, because high light levels improve the plant quality and the stems elongation. In winter and in early spring additional assimilation light is required for pot plant and cut flower production. Night interruption is possible. A short day period can be used to control the plant growth. 2-5 weeks after transplantation cultivate at short day (10 h) conditions for 7-10 days for a compact plant growth. Afterwards return to long day conditions (14-16 h) again.

Temperature:   Grow at 18-20 °C 64-68 °F. R. hirta needs warm temperatures for the growth. Temperatures of 16 °C 61 °F increase the cultivation time by 3 weeks. Temperatures below 16 °C 61 °F can be a cause for red colouring of leaves. R. hirta does not tolerate frost.

Fertilization:   Moderate fertilization levels are required. Fertilize the crop weekly with 100-150 ppm nitrogen (at 0 kg/m³ slow release fertilizer in substrate), using a potassium balanced fertilizer (N: K2O-ratio: 1:1.5). Avoid high ammonium and high nitrogen levels. Prevent magnesium deficiency by applying magnesium sulphate (0,05 %) 1-2 times and in case of iron deficiency (above pH 6.0) apply iron-chelate for 1-2 times. Field: Take care of possible iron deficiency and apply iron-chelate for 1-2 times. N min soil value: approximately 130 g N/m².

Cultural Hints:   Keep humidity low and provide good ventilation. Avoid over watering and drought stress. Drought stress can be a cause for necrosis of leaves edges. Avoid over head irrigation and avoid late day watering to reduce the risk of Botrytis especially at cooler growing conditions.

* Germination Stages (from seed to finished young plant)
Stage I: Starts with the radicle breaking through the testa. The roots are touching the medium. Ends with fully developed cotyledons.
Stage II: Starts from fully developed cotyledons. Ends with the fully developed true leaf or true leaf pair.
Stage III: Starts from the fully developed true leaf or true leaf pair and ends with 80% of the young plants being marketable.
Stage IV: All young plants are ready for sale and in the process of being hardened off. This stage lasts about 7 days.

Hint:
The cultural recommendations are based on results from trials conducted under Central European conditions. Different conditions in other parts of the world may lead to deviations in results achieved.