How to prepare poinsettias for the holidays

Garden Q&A

To get color, plants need hours of darkness for two months

December 04, 2013|By Ellen Nibali, For The Baltimore Sun

I saved my poinsettia from last year and it grew happily all summer. I put it in a closet two months ago to make it bloom red again for the holidays, but it is turning yellow instead. What should I do?

Poinsettias need bright indirect light to survive. Here's how to get them ready for the holidays: Since poinsettias initiate flowers as days get shorter, any additional light from artificial sources will prevent flower development. To get color for the holidays, give plants no more than 10 hours of daylight and then place them in at least 14 hours of darkness each day. This can be done by placing plants under a box or in a closet each evening from 5 p.m. to 7 a.m. for about two months, generally October and November, so they are ready in December. Even a small light leak will prevent flowering. The plants are not as light-sensitive once color has developed in the bracts. The most common problem of delayed flower development is caused by lighting during the darkness period. Go to for full poinsettia care, such as watering. In winter, water when the top inch or so of potting soil dries. When the pot is in a foil wrapper, remove it to water or poke holes in the foil, then place the pot in a saucer and water.

Will it hurt my liriope if I prune it now? It grows along my sidewalk and makes shoveling snow difficult.

Liriope has done plenty of growing already, and pruning will not kill it. However, as long as the leaves are green it's carrying on photosynthesis and producing carbohydrates to store, so you may want to wait for a snow forecast before you cut it back.

Is it too late to divide and transplant my ligularia?

While almost all perennials can be transplanted in fall as long as the soil is not yet frozen, ligularias are an exception and division should be done only in the spring. It is recommended to divide ligularia every three years to maintain vitality. Be careful to ensure that they never suffer dry soil.

Plant of the week

Winterberry holly

Ilex verticillata

Winterberry, our native wetland holly, makes a stunning specimen for the winter garden. Its autumn leaves turn yellow and fall to reveal a breathtaking view of thousands of brilliant red berries clinging to bare stems. What a joy to have such color in the middle of winter. Bird watchers appreciate seeing birds flock to the berries for a midwinter feast. Winterberry reaches heights of 6 to 10 feet with equal spread and is also available in dwarf varieties such as Maryland Beauty. Plant in moist, acidic organic soil. Females set fruit best in full sun and require a male pollinator. Some female varieties must be matched with a particular male variety. —Shelley McNeal

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