Home & Gardens: Using old Christmas trees as mulch | PostIndependent.com

Home & Gardens: Using old Christmas trees as mulch

Curt Swift
Free Press Gardening Columnist
Evergreen Branches
Getty Images/iStockphoto | iStockphoto

Millions of evergreens are cut for Christmas trees each year. The United State requires between 35-40 million trees, most of them being grown by upwards of 20,000 growers. Many trees are used to make wreaths and other holiday decorations.

What to do with these trees after the holidays is always a problem. Instead of sending them to the landfill where they take up much needed space, drop them off at the compost site on Orchard Mesa near the land fill.

They can also be used around the garden as mulch over strawberry beds or perennial flower beds. Boughs of evergreens placed over compost piles help retain heat, allowing the compost to continue working during the winter. Mulch shredded from Christmas trees can be applied around trees and shrubs and added to garden areas in anticipation of being spaded in next spring. Mulch from Christmas trees can also be used to start a new compost pile next spring.

Here’s another tip: If you wait until they dry out, they can even be converted into biochar, which when added to your gardens will increase plant growth and production. Wet snows can cause a great deal of damage to trees and shrubs. Limbs can be bent to a point where they never recover or they can be broken due to the weight of the snow. Broken branches will need to be removed either now or in the spring.

If removing a broken branch this winter, leave a six inch stub. This helps reduce winter dehydration in the main stem or trunk of the tree. This condition is called “black heart disease” and seals off much of the water and nutrient-conducting tissue of the tree in addition to walling off any stored food reserves in the “black heart” area. These reserves are needed by the tree in the spring to produce adequate growth and the bio-compounds necessary to ward of disease and insect attack. The stub should be removed next spring after all chances of freezing weather is over.

When we have wet snow storms, you may need to brush the snow off trees and shrubs several times to prevent buildup (which results in tree damage). Don’t beat the branches to knock snow off as this can cause injury to the bark, increasing chances of disease problems in the spring.

Arborvitae and other upright growing trees can be permanently damaged when wet snows bend the long upright branches to the ground. These branches do not rebound and the tree usually retains a ragged look. Arborvitae trees are often wrapped with twine or rope to prevent this damage and retain the shape of the tree.

The problem with this wrapping technique is the trees tend to lose their ability to keep their shape if the wrap is left on for several years. When branches are broken, they should be removed as soon as possible (leaving the stub I mentioned above). Leaving broken branches on the tree may result in more breakage and stripping of bark from the trunk.

Globe willows, due to their open vase structure, might split down the trunk due to the weight of the snow. If the split is not excessive, bracing and cabling the tree will help pull the tree back together and hopefully give it new life. Bolting the trunk back together may not be the best technique depending on where the bolts are installed. Cabling needs to be a specific height above the split, otherwise the tree can break off at the bolts.


The little, black, flying insects infesting house plants and indoor gardens at this time of year are fungus gnats. The adults are mainly a nuisance, but the larvae, which live in the soil, can cause root damage and spread disease. This can result in plant stress and plant death.

One way to reduce the numbers of this insect is to let the soil dry out between waterings. However with many plants, drying them out can result in reduced production.

If you have a lettuce crop growing in soil infested with fungus gnats, you certainly don’t want to dry out the planting as it will most likely kill the plants. If you a growing cannabis, you don’t want to dry out the plants as the stress of dehydration will significantly reduce yield.

The use of yellow sticky tape captures the adults only. To control the maggots, you should apply a product such as Gnatrol® to the soil or other rooting medium. This organic-approved product consists of Bacillus thuringiensis israelensis, a bacterium specific to fly larvae.

GJ Free Press columnist Dr. Curtis E. Swift is a retired horticulture agent with the Colorado State University Extension. Reach him at Curtis.Swift@alumni.colostate.edu, 970-778-7866, or check out his blog at http://SwiftsGardeningBlog.blogspot.com. He owns Swift Horticultural Consulting and High Altitude Lavender.

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