Scheduling

Since the poinsettia is a holiday plant, it is extremely important that flowering be properly timed. Plants that are in flower too early can be overmature when the customers purchase them. Plants that are not yet in flower in time for Christmas sales are worth little or nothing.

Keeping quality of recently introduced cultivars is so much improved over the lasting ability of most previous cultivars that early flowering is not as detrimental as it used to be. The grower should still attempt to schedule the flowering of the crop so that customers do not get plants that have pollen shedding, nectar dripping, cyathia dropping, or faded bracts at time of purchase.

Supplying "Long Days" and "Short Days"

The poinsettia is a short-day plant and can be scheduled to bloom. Flower bud initiation occurs when the daylength is about 12 hours and 15 minutes (but some cultivars do vary) at night temperatures less than 70°F (21°C). This daylength occurs in late September at a latitude of 35°N. Flowering can be delayed by subjecting plant to artificial long days in mid-September, and the plants will remain vegetative until short days (long nights) are started. Just writing when short days are to begin is not enough to make it happen. Insure that plants are indeed subjected to long day conditions when the schedule calls for long days. Supply a four hour night break (10 to 20 footcandles minimum at canopy level) or extend the daylength to a total of at least 14 hours to assure long days. Lighting to assure long days should begin September 5 for 'Freedom'; September 15 is an adequate starting date for most other cultivars. October 5 is a conservative starting date for natural short days in the Southeast, especially during a hot autumn when night temperatures may hover at or above 70°F. Night temperatures above 70°F can delay floral initiation in many poinsettia varieties and should be avoided under short day treatments. If your schedule requires short day conditions prior to October 5, blackcloth should be used to restrict daylength to a maximum of 11 hours (give at least 13 consecutive hours of darkness each 24 hours). Controlling photoperiod (and night temperature) is essential in precise programming of poinsettia market date and final height. Poinsettias are particularly sensitive to stray light during the flowering process which can delay flowering (see: Light Pollution).

Freedom plant subjected to varying start of short days (SD).
Click on image for larger version. (image © P. Allen Hammer, Purdue University)

Dark Red Hegg plant subjected to varying start of short days (SD).
Click on image for larger version. (image © P. Allen Hammer, Purdue University)

Freedom plant subjected to varying hours of light.
Click on image for larger version (image © P. Allen Hammer, Purdue University)

Timing

The number of weeks required for several cultivars to come into flower after the start of short days has been determined for North Carolina. Growers can more easily time their poinsettia crops if they know the response groups to which their cultivars belong. Timing will vary by location, so growers need to keep accurate records and adjust their schedules to meet local conditions. Timing is also affected by temperature and light, so growers should review those sections. Generalized production guidelines for scheduling a poinsettia crop may helpful.

Variety

Bract Color

Cyathia Visable

Anthesis

Response Time (weeks) ¹

Final Height (inches) ²

Flowering Shoot Count

Bright Red Freedom

10/20

10/29

11/20

7.0

10.5

5

Coco Red

10/18

10/25

11/18

7.0

15.5

6

Cortez Candy

10/30

11/02

11/23

7.5

16.5

9

Cortez Purple Rose

10/27

11/01

11/23

7.5

14.0

6

Cortez Red

10/29

11/02

11/27

8.0

18.0

8

Cortez White

10/29

11/01

11/24

7.5

14.0

8

Cranberry Punch

10/20

10/26

11/18

7.0

11.5

6

Darlyne Pink

10/28

11/01

11/28

8.0

11.0

5

Elegant Red

10/24

11/08

none

8.0

15.0

6

Festival Red

10/18

10/29

11/19

7.0

14.0

5

Flirt

10/28

11/01

11/22

7.0

15.0

8

Freedom Jingle Bells

10/21

10/28

11/18

7.0

9.0

7

Freedom Marble

10/28

10/31

11/22

7.0

10.0

5

Freedom Pink

10/25

10/28

11/19

7.0

10.5

4

Freedom Red

10/18

10/27

11/18

7.0

10.0

5

Freedom Rose

10/18

10/25

11/16

7.0

11.0

5

Freedom White

10/25

10/27

11/18

7.0

10.5

5

Galaxy Red

10/16

10/24

11/15

6.5

15.5

7

Heirloom Pink

10/25

10/27

11/17

7.0

13.5

6

Liberty Bright Pink

10/29

10/30

11/22

7.0

11.0

5

Liberty Bright Red

10/15

10/30

11/22

7.0

12.0

7

Malibu Red

10/20

11/01

11/23

7.5

10.0

4

Malibu White

10/28

11/01

11/29

8.0

9.0

6

Marblestar

10/25

10/30

11/20

7.0

14.0

6

Maren

10/23

10/31

11/18

7.0

17.0

8

Monet

10/29

11/03

11/26

8.0

11.0

7

Monet Twilight

10/30

11/03

11/30

8.5

10.0

5

Monterey Pink

10/26

10/28

11/22

7.0

14.0

5

Nobelstar

10/22

10/30

11/18

7.0

15.0

6

Nova Red

10/17

10/29

11/22

7.0

18.0

8

Nutcracker Pink

10/26

11/01

11/22

7.0

12.0

6

Nutcracker Red

10/20

11/01

11/23

7.5

11.0

4

Nutcracker Salmonstar

10/24

10/30

11/20

7.0

13.0

6

Nutcracker White

10/28

11/01

11/22

7.0

14.0

6

Orion Red

10/12

10/23

11/17

7.0

17.0

8

Pearl

10/25

11/01

11/24

7.5

8.0

5

Pepride Pink

10/15

10/24

11/18

7.0

8.5

6

Pepride Red

10/13

10/23

11/19

7.0

12.0

6

Peterstar Jingle Bells

10/22

11/01

11/24

7.5

11.0

4

Peterstar Marble

10/25

10/31

11/20

7.0

11.0

5

Peterstar Pink

10/25

11/01

11/22

7.0

10.0

5

Peterstar Red

10/19

10/31

11/22

7.0

12.0

5

Peterstar Silverbells

10/25

10/29

11/21

7.0

10.0

6

Peterstar White

10/26

11/01

11/24

7.5

9.0

5

Petoy

10/22

10/31

11/23

7.5

12.0

6

Pink Splendor

10/29

10/26

11/23

7.5

12.5

6

Puebla

10/26

10/27

11/18

7.0

15.0

8

Red Baron

10/26

11/03

12/01

8.5

10.5

6

Red Satin

10/24

11/05

11/29

9.0

11.0

6

Red Splendor

10/31

10/27

11/23

7.5

12.0

8

Red Velvet

10/22

11/02

11/27

8.0

11.0

6

Silverstar Red

10/17

10/26

11/19

7.0

14.0

7

Snowcap

10/27

11/01

11/24

7.5

12.0

8

Sonora Jingle

10/23

10/30

11/22

7.0

16.0

7

Sonora Marble

10/28

10/31

11/27

8.0

13.0

5

Sonora Orange

10/25

10/27

11/22

7.0

13.0

7

Sonora Purple Rose

10/21

10/28

11/23

7.5

14.0

8

Sonora Red

10/21

10/30

11/24

7.5

17.0

8

Sonora White

10/25

10/28

11/21

7.0

14.0

6

Spotlight Dark Red

10/23

10/30

11/22

7.0

19.0

6

Spotlight Pink

10/30

11/01

11/23

7.5

18.0

6

Starlight White

10/22

10/27

11/18

7.0

13.0

6

Success Coral

10/23

11/04

11/29

8.0

12.0

6

Success Light Pink

11/01

11/04

11/28

8.0

12.5

7

Success Pink

11/02

11/08

12/05

9.0

10.0

5

Success Red

10/24

11/06

12/02

9.0

11.0

6

Supjibi

10/23

10/30

11/23

7.5

8.5

5

Victory Red

10/21

10/31

11/22

7.0

12.5

5

White Splendor

11/10

10/29

11/25

7.5

12.0

5

Whitestar

10/23

10/28

11/21

7.0

14.0

7

Winter Rose Dark Red

10/27

10/24

11/30

8.5

16.5

6

Xenia Deluxe Red

10/18

10/29

11/23

7.5

12.0

6

¹ The response group was calculated as the number of days from October 1 until anthesis. The plants were grown under natural season conditions. Because Elegant Red did not reach anthesis, the date of 11/26 was used.

² Potting dates and cutting quality varied among the varieties, which influenced the final plant height.

Hegg Types, Lilo, Supjibi, Celebrate 2, Merrimaker, Yuletide, Freedom

Activity

Single Stem, 3 plants / 6" pot

Pinched, 1 plant / 6" pot

Flower

November 26

Flower

December 10

Flower

November 26

Flower

December 10

Propagation

July 30

(4 weeks)

Aug. 13

(4 weeks)

July 16

(4 weeks)

July 30

(4 weeks)

Pan

Aug. 27

(2.5 weeks)

Sept. 10

(1 week)

Aug. 13

(3 weeks)

Aug. 27

(3 weeks)

Pinch

---

---

Sept. 3

(1.5 weeks)

Sept. 17

(0 weeks)

Lights On

Sept. 15

(1.5 weeks)

Sept. 17

(3 weeks)

Sept. 15

(1.5 weeks)

Sept. 17

(3 weeks)

Lights Off

Sept. 24

(9 weeks)

Oct. 8

(9 weeks)

Sept. 24

(9 weeks)

Oct. 8

(9 weeks)

Flower

Nov. 26

Dec. 10

Nov. 26

Dec. 10

Night Temperatures

July 30 - Aug. 26

(70°F)

Aug. 13 - Sept. 10

(70°F)

July 16 - Aug. 12

(70°F)

July 30 - Aug. 27

(70°F)

Aug. 27 - Nov. 26

(65°F)

Sept. 11 - Dec. 10

(65°F)

Aug. 13 - Nov. 26

(65°F)

Aug. 28 - Dec. 10

(65°F)

Source: P.A. Hammer, Purdue University

V-14 Types, Peppermint, Regal Velvet, Red Sails

Activity

Single Stem, 3 plants / 6" pot

Pinched, 1 plant / 6" pot

Flower

November 26

Flower

December 10

Flower

November 26

Flower

December 10

Propagation

July 30

(4 weeks)

Aug. 13

(4 weeks)

July 9

(4 weeks)

July 23

(4 weeks)

Pan

Aug. 27

(2 weeks)

Sept. 10

(2 weeks)

Aug. 6

(3 weeks)

Aug. 20

(3 weeks)

Pinch

---

---

Aug. 27

(2 weeks)

Sept. 10

(2 weeks)

Black Cloth

Sept. 10

(1.5 weeks)

---

Sept. 10

(2 weeks)

---

Natural Days

Sept. 24

(9 weeks)

Sept. 24

(11 weeks)

Sept. 24

(9 weeks)

Sept. 24

(11 weeks)

Flower

Nov. 26

Dec. 10

Nov. 26

Dec. 10

Night Temperatures

July 30 - Aug. 26

(70°F)

Aug. 13 - Sept. 10

(70°F)

July 9 - Aug. 6

(70°F)

July 23 - Aug. 20

(70°F)

Aug. 27 - Nov. 26

(65°F)

Sept. 11 - Dec. 10

(65°F)

Aug. 7 - Nov. 26

(65°F)

Aug. 21 - Dec. 10

(65°F)

Source: P.A. Hammer, Purdue University