Temporary Storage of Evergreen Trees, both Bare Root and Plugs
When you receive your evergreen trees, open them immediately check to see if they are packed inside closed plastic bags [during the cooler months of the year] or in stretch wrap with their tops exposed [plugs during the warmer months of the year]. If they’re inside closed bags, open up the bags and roll the tops of the bags down to expose the needles to fresh air to avoid mold or mildew from developing on the needles, but keep the bags snug around the roots to reduce moisture loss due to evaporation. NEVER set packaged trees in direct sunlight due to the resulting miniature greenhouse effect, as they quickly overheat due to little or no ventilation. The plastic bag will quickly fog up as they use up their water reserves trying to transpirate the heat away, resulting in horrendously high heat and humidity, killing needles and entire trees as mold and fungus start taking hold.
Store your bundles of evergreen trees upright on the floor in your cool garage, porch or basement out of direct sunlight [sunlight on a closed or even open bag will cause a greenhouse effect]. The north side of your house or garage is actually the best storage location, since the trees will pick up on the rhythm of the weather outside and naturally acclimate to your specific conditions. Just make sure rain or roof runoff cannot enter the bags and drown your trees.
Bare root evergreen trees should be fine for up to a week or so using the methods described above if kept below 60 deg F, and plugs can be kept for a couple of weeks this way. NEVER put your trees in a freezer…the thermal shock of going from cool Spring/Fall temperatures to suddenly the middle of “freezing winter” [or vice versa] will kill many or all of them.
Plugs are generally packed with the green tops already open to the air to allow for transpiration [humans sweat, plants transpirate]. Check twice per week to be sure that the soil plugs have not dried out, and be sure give the trees some water just before preparing or planting them.
Always hydrate your trees BEFORE planting, and then water again after planting. The soil plug of plugs can simply be dipped for ten seconds, whereas bare root should be soaked in a bucket for an hour or three to super-hydrate the tree.
And always plant as soon as possible, unless you are experiencing appallingly high temperatures. If you are experiencing an excessive but short term heat wave, it is better to continue to store your trees as described above until cooler heads prevail.
Store Outside The Natural Way, By Heeling In
“Heeling in” evergreen trees is an old and trusted method of temporary storage of live plants such as evergreens. To heel your trees in, choose a sheltered, shady site and dig a V-shaped trench wide enough and deep enough to accommodate the plants’ roots, and long enough for all of the bundles you’ve purchased. Place each entire bundle of trees as is in the trench and lean them to one side, making sure all roots are below ground level. Refill the trench with soil (don’t pack it down) and water the trench area thoroughly. Check the soil moisture occasionally and water as needed. The trees are now stored in the best possible place: outside and in the ground, where they get fresh air and water, and can properly acclimate to your local/seasonal weather.
“You can leave plants heeled in for months, but I would suggest holding them that way only for a few weeks,” says Amy Grotta, extension faculty in forestry education at Washington State University. “You don’t want them to break dormancy before planting.” By that she means that plants that come out of dormancy too early are susceptible to frost damage, so plant earlier rather than later to prevent harming your new purchases.