Our previous HORT COCO blog (December 17, 2024) focused on caring for live holiday plants, including live Christmas trees. This article will focus on how to plant and care for a live tree after the holidays. As previously noted, the tree should not be kept inside for more than about 10 days, so take it outside as soon as you can. If you are planning to keep the tree for the future, place it in a protected area to allow it to adjust to the cooler outdoor environment. A protected area which gets good light but not too much direct sun, or an unheated greenhouse is good.
Depending on the variety of your tree, you may choose to keep it in the container, to be brought inside each year. Alternatively, you can plant it out in the landscape. Trees that will be planted out can stay in the pot until early spring, when the weather is better. Don't let the roots dry out.
Points to consider when choosing a spot for your tree
• The mature size of the tree—is there enough space? Some conifers can grow very large. If you don't have a suitable location, think about donating the tree to a non-profit organization or to a friend with a larger landscape. A slow-growing tree, such as the Dwarf Alberta Spruce shown in the photo, may do well outdoors in a container for a number of years.
• At least 6 hours of sun. But be aware that many conifer trees sold for the holidays are native to colder winters and cooler summers than we experience in Contra Costa. Although these trees need plenty of sunlight, some afternoon shade is helpful, especially when the tree is small.
• Good drainage. Most trees, including conifers, do not do well in soil that is too wet. If necessary, plant in a raised bed.
• Irrigation. A newly planted tree will need regular watering for the first few years, even if the variety is drought tolerant when mature.
How to Plant
• Follow established guidelines for planting trees.
• Dig the hole wider but NO DEEPER than the root ball. Plan to plant a little high so that the bottom of the trunk is slightly above soil level.
• Don't amend the soil—roots need to be encouraged to grow out into native soil.
• Wash the soil off the root ball, spread out the roots, and prune off any that are kinked or circling.
• Place the tree in the hole with roots spread out, checking that the root crown is just above grade. Backfill with native soil and water in. Add several inches of mulch, keeping the trunk area free of mulch.
• A small conifer is not likely to need staking—it's better to avoid this if possible.
• Water regularly—don't let the roots dry out or stay too wet.
For more information: https://anrcatalog.ucanr.edu/pdf/8046.pdf
Help Desk of the UC Master Gardeners of Contra Costa County (SMW)