Download Topic #2172 Foliage Plants

Topic #2172 Foliage
Plants
Focus on Poinsettias
By: Alisa Kowalski
Major Foliage Crops
1. Poinsettias
2. Chrysanthemums
3. Easter Lilies
4. Florist Azaleas
Minor Foliage Crops
1. African Violets
2. Cineraria
3. Cyclamen
4. Holiday Cacti
5. Kalanchoe
6. Gerbera Daisy
7. Gloxinia
Poinsettias I
• Euphorbia pulcherrima
• Native to Mexico
• Named after Joel Poinsett,
former US Ambassador to
Mexico
Poinsettias II
• #1 Potted Flowering Crop in US
• Wholesale Value: >$123
million/year
• Grown for showy bracts which
are modified leaves
Poinsettias III
• Cyanthia- small, yellow, bud
shaped structures in the center
of the bracts (flowers)
• Short day or long night plant
• Require at least 12 hours of
darkness
Poinsettia Cultivars
• Annette Hegg Series
• Echespoint Series
• Gutbier Series
• Mikkelsens Series
Poinsettia Cultivation
• Vegetatively propagated by tip
cuttings
• Available rooted or unrooted
Poinsettia Stock Plants I
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Cuttings received in March-May
Night interruption lighting
Prevent flower initiation
After rooting
– 6”-10” pot
– 50ºF- Night Temperature
– 80ºF- Day Temperature
Poinsettia Stock Plants II
• 2 Pinches before cutting
• First pinch
– leave 8-11 nodes
– 7-10 days after planting
• Following pinches
– leave 2 nodes on new growth
Poinsettia Cuttings I
• Cuttings taken~4 weeks after
last pinch
• Key factors to success
– Cleanliness
– Mist System
– Optimum Temperatures
• 3-4 inches using hands or knife
Poinsettia Cuttings II
• Place in
– 6 inch pot or
– artificial media
• examples: rock, wool, or foam
– Mist system immediately
Poinsettia Cuttings III
• Bottom heat
– speeds rooting
– Media temperature 70°F -75°F
• Misting leaches nutrients
– 7-10 days after planting
– use a 150ppm-200ppm
fertilizer solution
Poinsettia Cuttings IV
• Misting
– decrease interval after
callusing
• Remove from mist
– when good roots have formed
– put in final spacing at this time
Growth Requirements ~
Media
• Good Example of Media: Equal
parts
loam soil, peat moss
and perlite
– High porosity
– High water holding capacity
– Sterile
– pH= 6.0 to 6.2
Growth Requirements ~
Watering
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•
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•
Require large amounts of water
Should not be allowed to wilt
Overwatering can cause root rot
Examples of watering systems
- Spaghetti tubes
- Capillary
mats
- Subsurface Irrigation - With hose
Growth Requirements ~
Fertilizing I
• Large amounts of fertilizer
requirements Especially Nitrogen
• Constant liquid feed of 250-300 should
fulfill the requirement for established
plants
• Amount required may be affected by:
– light & temperature levels
• Weekly pH & EC test is suggested to
measure the effect of these
Growth Requirements ~
Fertilizing II
• Poinsettias are sensitive to ammonia
toxicity
– Caused by an excess of 305 Ammonium
nitrogen
• Calcium deficiency can cause bract
necrosis & weak stems
– To combat this a trace element mix should
be added once during production
Growth Requirements~
Temperature I
• Average Daily Temperature
affects development
• To enhance bract color
– During finishing reduce night
temperatures to 55-60F
Growth Requirements~
Temperature II
• Average Daily Temperature affects
development
• Optimal temperatures
– Night- 65F
• If below- delay flower initiation
– Day- 70-75F
• If above- reduces flower quality
Growth Requirements ~ Light
• To keep plants vegetative
– Night interruption of 10 fc from 10 PM to 2
AM
• High light levels during the day influence
growth
• Plants will bloom when days are less than
12 hours
– A black cloth may be used to shield plants
from outside sources of excess light
Growth Requirements ~
Pinching
• No Pinching = One Large Flower
• Most plants are pinched 2-3
weeks after transplanting & once
the plant has established a
sufficient root system
• It is common for plants to be
pinched to 3-5 nodes
Growth Requirements ~
Pinching
• Top 1/2 to 1 inch of plant is removed
• More nodes left on stem = more
flowers
– If more flowers are allowed to form, they
will be smaller that if fewer flowers were
to flower
Growth Requirements ~
Height Control I
• Controlled by adequate spacing
• If plants are shaded they will stretch
& elongate
• DIF can also be used
– A DIF of 0 to a negative number can
slow growth
Growth Requirements ~
Height Control II
• Chemicals can also be used
• Common Chemicals include:
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Cycocel
B-nine
A-rest
Bonzi
Sumajic
• Be Sure to Read the Label and Instructions!
Problems for Poinsettia
Growers
• Insects
– Whitefly
– Fungus Gnat
• Use IPM to control these insects
Diseases of Poinsettias
• Bostrytis- gray mold
– Prevent by providing low humidity and
good air circulation
• Rhizoctonia- stem and root rot
– Control with fungicide
• Pythium- water mold and root rot
– Control with fungicide drench
Physiological Problems I
• Bract Burn- Condition in which tips of
bract turn brown
– Controlled by not applying high ammonium
fertilizers and maintaining calcium levels
• Center Drop- Condition in which flower
buds abscise due to carbohydrate
depletion
– Controlled by maintaining proper temperature
and maximizing light penetration
Physiological Problems II
• Stem Splitting-Condition in which
the terminal bud is aborted and
three shoots develop into a whorl
– Controlled by providing
appropriate night temperatures
Post Harvest & Handling
• Cool finishing temperatures and
lessen fertilizer applications
• Plants should be sleeved to ship
and unsleeved as soon as possible
to minimize droopy leaves
• Plants should be stored at 5060F and in bright lights