Lights, Plants and Trees
Q: Can Christmas lights harm plants?
A: Christmas lights don’t pose a serious threat to plants; however, depending on the types of lights and how you use them, they can cause some minor damage. For example, large bulbs can create enough heat to actually burn leaf surfaces. If you like to light evergreen shrubs, use only light strands that come with tiny bulbs.
Also, when decorating small deciduous trees and shrubs that have brittle branches during the winter months, the weight of the light strands may break the branches, especially when you try to remove the lights after the holidays.
Floodlights and spotlights–whether used year-round or just for the holidays–can also cause damage, because they too can generate so much heat that they actually scorch nearby plants, especially evergreens. Make sure you position floodlights and spotlights a foot or two away from plants, and consider switching them off at some point during the night. You might consider using the lowest watt bulb available, because a 45-watt bulb produces less heat than a 90-watt bulb.
Q: What’s the most environmentally responsible way to dispose of a Christmas tree?
A: The most environmentally responsible thing you can do is buy a live Christmas tree and plant it after Christmas. First, move it from the house to the garage for a day or two; then, stick it in the ground.
Many cities provide chipping services at no charge to convert your tree into mulch, and some offer free pickup and free mulch.
Those who manage lakes often welcome Christmas trees, which they weight and sink in the water to create habitats for crappie and other fish species. You can also pile a few trees in a corner of your property to provide habitat for birds, rabbits and other critters.
Q: Is mistletoe harmful to trees?
A: It can be. In fact, it might even kill your tree. Mistletoe is a semi-parasite. Its berries–which are poisonous to humans–are eaten by birds who deposit the seeds within the bark of trees where they germinate. If allowed to spread throughout the canopy of a tree, mistletoe can be poisonous, which is why it’s a good idea to knock it off with a long pole if you find it growing in one of your trees.
Q: What is heaving, and how can I prevent it?
A: Alternating periods of freezing and thawing can cause plants to heave out of the ground. In some areas of the country, heaving can be a real problem. The best way to prevent it is to wait until after the first hard freeze, then apply a thick layer of mulch to landscape beds. The mulch will insulate the soil and maintain it at a fairly constant temperature rather than allow for wide-temperature swings which result in heaving.