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 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 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 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  F

Growth Requirements~ Temperature II Average Daily Temperature affects development Optimal temperatures –Night- 65  F If below- delay flower initiation –Day  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: –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  F and in bright lights