By Kirsten Conrad, Extension Agent for Arlington County and the City of Alexandria
Helping your tree survive its time indoors is a high priority for those who spend money on a live tree with the intention of replanting it outdoors when Christmas is over. Tree owners need to remember that the single most important goal is to keep the moisture level of the tree needles and twigs as high as possible and prevent it from drying out, suffering needle drop, and possibly dying.
Right Tree, Right Place
Research the types of evergreen trees that will do well in your specific growing conditions. How big will each variety grow, and how fast it will reach maturity? Pick a native plant whenever possible as you will have fewer plant pest problems and it may be more adaptable to your backyard soils. Because many conifers are better adapted to temperature conditions in northern woods, be sure to check your plant’s heat tolerance zone on the American Horticultural Society’s heat map.
Most evergreen conifers require full sun and loamy well-drained soils that are slightly acidic. Some will grow quite large. Make sure that the place you are thinking of planting it will have enough room for it to grow for many years. Select a tree that’s right for your climate, soil and light conditions and buy early. Most nurseries are happy to order a tree for you or to tag your selection and hold it in the nursery for you.
Here are some ideas for Virginia tree selections:
- Pinus strobus, (Eastern White Pine)
- Fraser fir (Abies fraseri)
- White spruce (Pica glauca),
- Virginia pine (Pinus virginiana), and
- Thuja occidentalis, (Arborvitae, Northern Whitecedar)
If the ground is likely to freeze hard before you plan to plant the tree outdoors, it is wise to dig the hole before soil freezes. Be sure the hole is large enough to spread out the roots when planting. This is an opportunity to check and correct the soil acidity. Most conifers prefer a slightly acid soil; you can adjust the pH level using various soil amendments over the larger growing area. For a soil test kit and more information, contact your local Extension office.
Beware the Spotted Lanternfly
2020 Update: Christmas trees grown or shipped from inside the Spotted Lanternfly quarantine areas that include Pennsylvania, New Jersey, northwestern Maryland, and Northwestern Virginia should be inspected carefully for signs of dead or living Spotted Lanternfly or Spotted Lanternfly egg masses.
Any sign of suspected SLF should be reported to your local Extension Office.
Egg masses can be removed by scraping into alcohol or hand sanitizer.
More information: Spotted Lanternfly in Virginia
Placement Is Important
Bring the tree home about 10–12 days before Christmas. Put the tree in a transition zone like a garage that has some light to get it used to being in a lower light and humidity environment. Keep it watered so that the ball doesn’t dry out. When you move the tree indoors, select a spot with filtered light and away from heating vents, direct sunlight, and drafts of air from fans. The cooler the location the better. You can stand it in a basin to keep the floor dry and clean, but avoid the temptation to over water and NEVER keep standing water around the root ball.
Do not leave the tree indoors for more than 8 to 10 days. Use only light strands with tiny bulbs and lay the strands across the tops of branches. Avoid wrapping them around the branches. After Christmas, move the tree back to the garage.
Remove grass and other plants from the base of the tree and the planting site. Spread the roots out and away from the root ball as much as possible to ensure that new rooting takes place in your native soil. Soil amendments are not needed in the planting hole but adding organic matter to the area that a tree is to be planted into will improve nutrient and water holding capacity.
Place the root ball in the hole so that the top of the root ball is higher than the grade of the surrounding soil by a minimum of 4 inches. Pull soil up the edges and lightly cover the top of the root ball. Mulch over all of the disturbed soil to help prevent grass and weed growth and help conserve soil moisture.
If you are planning to grow your tree in a container, it should be cold hardy to two zones more than your location. In Northern Virginia we are at hardiness zones 6–7 so choose a tree that is hardy for the colder temperatures of zones 4–5 for container plantings.
Newly planted conifers, in the ground or in containers, need one inch of water per week over the root zone. If the tree will be in a high wind situation, you may wish to stake it for the first year to allow roots to take hold and get established.
After one year you may wish to work organic matter like composted leaves or decomposed old mulch into the soil along with a light feeding of nitrogen. Wood chips are an excellent mulch for trees. Replace annually or as needed.
Help with plant selection, planting, and maintenance of landscape plantings is available through the Extension Master Gardener Help Desk at the Fairlington Community center. Walk in, phone, and email assistance is available weekdays from 9 a.m. to noon. We provide education on insects, plant disease, household pests, weeds, and more.
Phone: 703-228-6414. Email: email@example.com.