Tropical Gardening Helpline: When and how to prune your poinsettias

  • Variegated poinsettia can be propagated, but may be patented and should not be resold. (Kim and Forest Starr/Special to West Hawaii Today)
  • Spring and late summer pruning of poinsettias can result in a gorgeous floral display in the winter holiday season. (Diana Duff/Special to West Hawaii Today)

Debbie asks: I vaguely remember hearing that poinsettia plants should be pruned in April and August. I have a few in the ground and some in pots. Should I be pruning them now?

Tropical Gardener Answer: Good vague memory. Yes, if you want an attractive poinsettia (Euphorbia pulcherrima) with lots of flowers next winter, “hard” pruning this April and shaping until August will help you achieve that goal.

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Usually, by April, most of the holiday season blooms will have faded. At this time you can reduce watering until you are ready to prune. In the April pruning, you’ll want to cut back all the stems to a latent or leafing bud that is low on the stem. This “hard” pruning establishes the plant’s structure from which flower and leaf bearing branches will grow. Wearing gloves when working with poinsettias is recommended in order to avoid contact with the milky sap which can be an allergen.

You can take the cuttings you removed and propagate new plants, if you like. Use stems that are a little thicker than a pencil and about 6 inches long. Dip them in rooting hormone, remove most of the leaves and put them in moist 50:50 mix of vermiculite and perlite. Place the cuttings in a bright location out of direct sun and keep the mixture moist (not wet) until new growth appears. Be aware that poinsettias are sensitive to root rot and other diseases if the growing medium is too wet.

The cuttings should develop new leaves and have a healthy root system in a few months. At this point, you can move them to a larger pot with soil or plant them out in the landscape and fertilize lightly. They will do best in an area that is lightly shaded or in direct sun only part of the day.

If you plan to sell any of your new plants just be sure that it is not a patent protected variety. Patent owners can sue you if you sell any of their protected varieties.

When new growth appears on your poinsettias, after the spring pruning, you can begin regular light watering. Again, don’t overwater. Poinsettias are somewhat drought tolerant and will grow best in soil that drains well and dries on top between waterings. If you want to keep the plant compact, you can pinch the tips of the new growth when it is at least six inches long. This will encourage branching below the tip.

To encourage heavy flowering in December, you can reduce your plants’ exposure to daylight starting in late September. Though the plants need light during the day to gather energy for flowering, covering them at night, keeping them in complete darkness for 12 hours, creates the ideal conditions for them to flower heavily.

Once blooming begins, usually in early December, put your poinsettia in a cool, bright spot with indirect sunlight where you can enjoy her vibrant blossoms.

Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.

Gardening Events

Monday: “Hawaii Tropical Fruit Growers Monthly Meeting” from 7-9 p.m. at West Hawaii Tropical Fruit Growers office 81-6393 Mamalahoa Highway, in Kealakekua. White wooden building on makai side across from the Department of Transportation yard. Park in front or on the north side. For more information contact Brian Lievens, president West Hawaii Chapter at 895-8753 or greenwizard@hawaii.rr.com.

Saturday: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Farmer Direct Markets

Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

“Waimea Town Market” from 7:30 a.m. to noon at the Parker School in central Waimea

“Waimea Homestead Farmers Market” from 7 a.m. to noon next to Thelma Parker Gym in front of Thelma Parker Library.

Sunday: “Pure Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook

“Hamakua Harvest” 9 a.m. to 2 p.m. at Highway 19 and Mamane Street in Honokaa

Plant Advice Lines

Anytime: konamg@ctahr.hawaii.edu

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Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892

Mon., Tues. and Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu

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