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Availability: In stock

  • Tall growing with strong, sturdy stems and numerous branches

  • Very high flower productivity

  • Being a triploid, Blue Horizon is very vigorous and easy to cultivate, having larger flowers than traditional Ageratum

  • Also suitable as a garden plant

  • Height about 75 cm (30 inches) with a spread of about 20 cm (8 inches)

€0.007 each
AGERATUM houst. BLUE HORIZON is available for purchase in increments of 500 seeds.



Ageratum Blue Horizon

Cultural Information for:     Ageratum Blue Horizon               Annual
Common Name:               Ageratum or Floss Flower
Botanical Name:                Ageratum houstonianum
Seed Count:                  19,800/ounce                           700/gram

Optimum Germination Temperature:                       77 ºF / 25 ºC

Optimum Growing Temperature:                            65 °F / 18 °C

Plug Stage – 5 weeks (288 / 12 x 24 tray)

Stage One (days 1-7)   Single sow pelleted seed into a well drained peat mixture with a pH of 5.8-6.2 and a low nutrient charge (EC < 0.5 mmhos/1:2 slurry).   Ageratum requires light to germinate so lightly cover with coarse vermiculite and maintain sufficient moisture to melt the pellet.   Optimum germination temperature is 78-82 °F/25-28 °C.

Stage Two (days 8-20)   After seed emergence move plug trays to a greenhouse with high light and good air circulation. Reduce air temperature to 60-70 °F/16-21 °C and apply a
light feed of 50-75 ppm N using a well balanced calcium
nitrate based formulation.

Stage Three (days 21-30)   Increase fertilizer level to 100-150 ppm N.   Optimum EC is 0.7-1.0 mmhos (1:2 slurry).   Allow the plants to dry slightly in between watering to reduce stretch and promote a strong, well-toned plant.   Growth regulation is not recommended for cut flower production. For ornamental use in containers where height control is desirable, apply B-Nine (daminozide)) at 2,500 ppm/0.25%.

Stage Four (days 31-35)   The plugs are approaching transplant stage.   Reduce fertilizer to tone the plants and prepare them for transplanting.   Do not delay transplanting.

Cut Flower Culture:

Media:   Select a well drained sterile cut flower bed in full sun with a pH of 5.8-6.2 and a low nutrient charge.

Watering:   Initially, keep the plants well moistened and then water as needed.   Growing too dry may result in red-edged or yellow leaves.

Fertilizer:   Well balanced calcium nitrate based formulations work well to build strong and healthy plants.   Optimum EC is
0.7- 1.0 mmhos.   Excess nitrogen promotes overgrowth,
invites disease and reduces vase life.
Lighting:   Optimum light level is up to 7,000 foot candles./
75,000 lux.   Whitewashing the glass may be necessary May- September to reduce light intensity.   Extending the photoperiod in winter to16 hours is recommended to ensure sufficient stem length and improve flower quality.

Temperature:   Optimum temperature is 60-70 °F/16-21 °C. For winter production maintain 60°F/15°C maximum. Temperature is more important than day length for winter flowering.   Under low light conditions do not grow too warm, (above
60°F/15°C), or else the stem quality will be reduced and tissue too soft.

Insects:   Aphids, White Fly, Thrips, Mites

Single Stemmed Culture:   Space plants 4 x 4 inches/10 x 10 cm. apart in beds and provide support netting.   Raise netting as the plants grow.   Do not pinch the plants.

Multiple Stemmed Culture:   Space plants 8 x 8 inches/20 x
20 cm. apart and pinch the growing tip to induce side branching.   This will result in a heavy crop of high quality cut flowers.

Harvesting:   For summer production allow 12 weeks from sowing and 15 weeks for winter production.   The first flower is usually removed to create a flush of flowers.   The flowers should be well-colored before cutting.

Container Culture:  

Pots:   For green sales in 4 inch/10 cm. pots place one plant per pot and plan on 4 weeks from transplant to shipping. Larger containers in color require 6-7 weeks from transplant.

Media:   Select a well drained sterile mixture with a pH of
5.8-6.2 and a low nutrient charge.

Growth regulation:   B-Nine is effective at 2,500 ppm/0.25%.

Culture watch points:   Avoid using Kelthane or Ortocides on the crop.   Ronilan damage seedlings.

Do not apply plant growth regulators during bud formation.

“Information copied from the breeder.
Muller will not accept any liability for failure and/or damage as a consequence of incorrect and/or inexpert cultivation by or on behalf of the Buyer.”