December Gardening Tips

Monthly Proven Tips and Solutions for Granite State Gardeners

greenhouse tools snow

Now is a great time to take cuttings from plants to be used for holiday decorations.

Hollies, red osier dogwood, winterberry, paper birch, and conifer boughs all make for great DIY holiday craft projects. If you haven’t already wrapped or protected any cold sensitive plants you can take your cuttings just prior to doing so. The bright red berries of wild winterberry can sometimes be spotted from the road. This beautiful native plant is often found in low, wet, boggy areas so be sure to wear your waterproof boots and get permission to harvest if they are on private property. Be mindful not to overharvest from one plant as this can reduce its vigor and affect future berry production. It is best to take a few cuttings from multiple plants instead. Resist the temptation to use invasive bittersweet vines for wreaths. While the berries are a vibrant red and orange, they will readily seed and can quickly take over the landscape and become an expensive challenge to manage. You can still enjoy their invasive beauty from a distance without contributing to its spread.

Keeping a cut Christmas tree fresh through the holidays can be a real challenge, especially if you have it up by December 1st or leave it up well into January.

To help the tree take up water cut a 1/4” disk off the end of the base of the trunk before putting it in the stand, especially if the tree was not cut the same day it was brought indoors. A fresh tree can absorb up to a quart of water per day for every inch of trunk diameter, so be sure check it daily and keep it filled. A strategically placed pitcher of water near the tree can be a helpful reminder. Tap water is all the tree needs so don’t bother with any additives like sugar, gel, or floral preservatives. Consider the location of the displayed tree and keep it away from heaters, wood stoves, direct sunlight, and air vents as these can lead to premature drying and increased watering requirements. An overly dry tree can be a fire hazard. Consider using LED lights which have become increasingly more affordable, generate little to no heat, and use significantly less energy to operate. If a cut or synthetic tree is not for you, consider a living Christmas tree, which can be planted in spring if properly cared for through the winter.

Containerized plants can survive the winter but may need a little extra attention.

Soil is more prone to freeze-thaw cycles in unprotected pots which can damage roots. It is also more difficult to regulate soil moisture in a pot, but there are a few strategies to help ensure survival. One option is to bury the pot in the soil outdoors before the ground freezes. Be sure to keep the top of the pot level with the ground. Smaller, lighter potted plants can be moved into an unheated room such as a garage or shed for insulation from extreme cold and wind. Monitor the pots because soil can still dry out in the winter. If the top few inches of soil are dry to the touch or the pot feels extra light, add enough water to moisten the soil, but not soak it. Too much water can lead to root rot. Plants can also be grouped together in a protected location outdoors. The pots should be surrounded with a thick layer of mulch such as leaves, wood chips, pine needles, or bark mulch to insulate from the cold.

Indoor plants require slightly different care in the winter months.

Many originate from tropical locations and have a very low tolerance of the colder temperatures and lower humidity New England homes typically experience in the winter months. Plants on windowsills may need to be moved to another location that is warmer and well-lit as windows can create cold drafts. Be sure not to move them near heaters, stoves, or air vents as this can burn the leaves and cause excessive soil drying. A humidifier can be placed nearby to help create a more favorable indoor environment. Many houseplants require less water in the winter months, so only water when the top few inches of the soil are dry to the touch. Water until it flows through the drainage holes in the pot, but don’t leave any sitting water if there is a saucer or catch under the pot. Winter is a good time to start thinking about which plants may be rootbound and need repotting soon. This is best done in the spring or summer when the plant is more vigorous and can recover from the stress of repotting.

It’s time to put the gardening tools away, but if you spend a little effort maintaining them they will last longer and perform better.

It can be difficult to find time for this during the busy growing season so finding a heated space to do a little maintenance is an ideal winter activity. Cleaning any dirt or corrosion from tools and applying a thin coat of oil with a rag can greatly extend the life of shovels, rakes, hand tools, and blades. Hand pruners, loppers, and mower blades can be sharpened by hand with a steel file, but be sure to follow the angle of the edge of the cutting blade. There are also plenty of knife and scissor sharpeners that can safely handle this task for a fee if you are not comfortable doing it yourself. Mowers, trimmers, chainsaws, tillers, and any gas-powered tools can be emptied of fuel into an approved container and run dry to prevent the fuel from going stale or gumming up carburetors. Another option is run ethanol-free fuel in your small equipment, which can be purchased at many hardware stores and sometimes found at airfields or gas stations near ATV recreation areas. Additives such as fuel stabilizers can also be used to extend the life of the fuel. If a piece of equipment is not going to be run for more than 6 months it is best to drain it completely, as even treated fuel will eventually go bad.

Winter salt use can be a major contributing factor to plant injury in your landscape, especially near walkways and roads.

While the outside temperatures have been unseasonably warm lately it’s a good idea to think head to help spare your plants. Salt spray from passing cars and plows can burn leaves, buds, and evergreen needles but the damage may not be evident until spring, after it’s too late to intervene. The most commonly used salt type is sodium chloride, or rock salt, because it is effective and inexpensive. Unfortunately, the sodium and chloride ions can accumulate in the soil where your plants reside and can be detrimental to plant health. One option to combat salt damage is to switch to a more plant-friendly salt source, such as calcium chloride, magnesium chloride, or potassium chloride. Another option is to dilute your salt by adding other materials such as sand, sawdust, or ashes for traction. While it is tempting to be heavy-handed when putting down salt, consider using just enough to get the job done regardless of which type you have chosen, or just opt for ice cleats when you go out. Trees and shrubs located near roads and driveways can be protected with a physical barrier such as burlap or wood. When planning future plantings it is a good idea to consider salt tolerant trees and shrubs if they are located near walkways, driveways, or the road.  


Do you love learning about stuff like this? 

SUBSCRIBE TO GRANITE STATE GARDENING

A monthly newsletter for New Hampshire gardeners, homesteaders and plant-lovers of all kinds, that includes seasonal suggested gardening tips, upcoming events and articles with proven solutions for your garden and landscape.

Got questions? UNH Extension's Infoline offers practical help finding answers for your home, yard, and garden questions. Call toll free at 1-877-398-4769, Monday to Friday, 9 a.m. to 2 p.m., or e-mail us at answers@unh.edu.

Author(s)

Ask UNH Extension
Master Gardeners & Extension Specialists
Phone: 1-877-EXT-GROW (1-877-398-4769)