Master Gardener Q & A
2017 Winterby Toby Day and Dara Palmer
Q. How do I keep my poinsettia alive and thriving after the holidays?
- Yellowstone County
A. Poinsettias, a traditional holiday plant, are native to Mexico. The beautiful red color on these plants comes from the bracts (or leaves), the flowers are the very small, not overly dramatic, yellow center. Poinsettias should be placed in an area with a temperature of 65-70 degrees, indirect sunlight, and out of drafts. These plants are very sensitive to overwatering and can easily develop root rot. Water your poinsettia when the soil is dry 2-3 inches down. Make sure your plant can drain properly by taking it out of the foil wrapper they usually come in or poke holes in the foil. You can mix an all-purpose fertilizer in your watering can if desired to keep the plant healthy and vibrant. Once the bracts fall off, usually around March or April, trim the plant back until only a few leaves remain; make sure and leave about 6-8 buds also. At this point your poinsettia likely looks like a stick; don’t give up on it yet. Maintain watering and by May it should begin to leaf out again. To regain that nice compact shape, trim the plant back in July. This will encourage new branch growth. Poinsettias need a period of 14-16 hours of complete darkness to develop their red bract color. October 1 place the plant in a dark closet for a minimum of 14 hours of absolute darkness. Bring it out during the day for 8-10 hours of indirect light, continue watering and fertilizing and by the end of November your poinsettia will begin
to color for another season of enjoyment.
Q. Is snow a good insulator for herbaceous plant material?
- Richland County
A. There are pros and cons to snow cover on your plants in the winter. Snow is a very good insulator of the soil. It helps protect the ground from cycles of freezing and thawing which can cause the soil to heave, therefore damaging the plant roots. In addition, snow aids the soil by helping it conserve moisture over the winter. Heavy, wet snow on the other hand can damage branches on trees and shrubs with its weight. It’s a good idea to shake the snow from your plants after a heavy, wet snowfall. Snow pack around landscape plantings is a good hiding place (and food source) for small gnawing animals such as voles and rabbits. This damage usually goes unnoticed until spring when the snow begins to thaw.
Q. What is winter desiccation injury and how do you prevent it?
- Missoula County
A. Desiccation injury occurs when water transpires through plant tissue faster than the roots can take it up. This typically occurs in the winter when there are long, dry periods of cold and thawing accompanied by windy conditions. Evergreen trees are highly susceptible. There are foliar sprays called anti-desiccants that contain a wax which coats the needles to help slow the transpiration process. They are marginally effective and can damage the plant if applied at the wrong time. A better approach is to physically protect the plant from exposure with burlap or a similar material (see diagram) and making sure the tree has adequate water throughout the fall and in the winter if there is little to no snow cover.
When creating a windbreak for the plant, use 3 stakes placed firmly in the ground in a “v” shape. The point of the “v” should face into the prevailing wind. Wrap burlap around the stakes, leaving enough space between the burlap and the plant so as not to rub in the wind. This method can also help decrease winter burn on evergreen plants such as Arborvitae.
Do you have Master Gardener questions? Send them to: extensionmagazine@montana.edu.