Why shouldn't I water a Blue Spruce tree during and after transplanting it?

Question

I live in Massachusetts, Northeastern United States, in Hardiness Zone 6, where the temperatures get down to −10°F (−23.3°C). We're getting to the coldest time right now, although so far this year has been a bit warmer than usual, so the ground isn't fully frozen.

On Friday, December 16th, we purchased a 4 feet tall living Blue Spruce (Picea pungens), to use as a Christmas tree. It was dug up on that day. (The tree was referred to in my previous question).

Since the whole point is to keep the tree alive, we've been careful to follow the instructions of the arborist from whom we purchased it.

While inside:

• Keep the rootball intact in its original burlap
• Put it in a tub with a diameter just a few inches larger than the rootball
• Water it every few days from the top, keeping the rootball moist but not soggy or sitting in a lot of stagnant water
• Keep it in a cool room if possible. (Our 3-season room stays in the 50s or so during the day and 30s at night. We've only heated it to room temperature for a few of the total number of days.)
• Don't use hot Christmas lights, and only leave them on for short periods of time

For planting:

• Before purchase, dig a hole at least 36 inches wide and 24 inches deep
• Plant the tree outside within 10 to 12 days
• Set it into the hole with the rootball level with the ground
• Backfill the hole with its own dirt and some light mulch or shredded leaves
• Don't water the hole, the dirt, the rootball, or the tree during planting
• Don't water the tree at all until about 3 months from now, at the end of March

We're planning on putting it out in a few days, and I have a question about the watering instruction. Is it true that we shouldn't water it? (Out of curiosity, if it shouldn't be watered, is that true of all trees or just evergreens?) If in fact we should water it, what would the regimen be?

I've never planted or transplanted a tree. However, in my experience with bushes and other plants, the hole and surrounding area should be wet, and once planted, a good soaking is required. Also, the area should be kept consistently moist during the initial settling-in period.

Obviously we don't water our other trees during the winter, so it makes sense that, once established, it would rely on the elements. What I don't understand is why we shouldn't add water after planting. How will the roots spread in the cold dry ground without an initial burst of assistance?

The pictures are of the tree inside; a close-up of the root ball in the pot; the entire planting hole; and a close-up of the bottom of the hole. The soil in the bottom of the hole seems clay-like. It's thick and slimy. It almost feels like mud, just not quite as wet.

Click on all pictures for bigger, closer views.

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Update: The tree is fine!

My husband planted it on the 11th day after it had been dug up. He did it by combining the advice from the arborist from whom we purchased it, the generous people who answered me here, and this excellent question/answer. He unfolded the burlap gently. It had no nails and no mesh bottom. Since the rootball was moist and holding together nicely, he removed the entire burlap. Without watering the hole, he gently laid in the tree at the proper depth, and backfilled it with the dirt from the hole, together with some other loose dirt and crushed leaves. No needles dropped and no branches fell. We're glad we didn't water it, as it rained the next day. We had our first deep frost that night, so the timing was perfect! It was a wonderful experience all around. I encourage people to use this method for their Christmas trees. The tree costs much less than it would from a regular nursery; adds to the landscape; provides a great place for birds and squirrels; and doesn't become a side-of-the-road casualty.

I didn't get any great pictures, but for reference as to location, we put it exactly where last year's pre-cut (not planted) Christmas tree was just sitting dead on top of the ground! More pictures of the area can be found in my previous question.

Click on the pictures for bigger, closer, views.

Answer 1

In my 25 years as a landscaper in the Pacific Northwest, I have never heard of such a treatment. With that said, the only thinking I can come up with is that the arborist feels that by watering in the tree, you will be overly compacting the soil, destroying the larger air pockets, and trapping excess water around the rootball which might cause rot. I would suggest calling the arborist and asking them to clarify their thinking.

I also wanted to comment that when you do plant the tree, after placing it in the hole, but before back filling, gently fold back the burlap and fold it down into the hole. I usually use the top of the vertical edge of the rootball as the line around which I fold. Often times the wrapping around the trunk is secured by a nail or two. Folding back the burlap is important because if the burlap is exposed to light/air the water around the tree will wick out through the exposed burlap.

Answer 2

Based on the picture, your soil looks quite moist enough already. By watering, you could cause problems in winter with constant saturation, because of the ground freezing. I'd say, if the soil holds its shape when squeezed into a ball, do not water. If the soil is crumbly and dry, then yes, water it even in winter. Sometimes I water a root ball before planting, because the root ball is dry and the soil it's going in is wet. In your care, the root ball has been kept moist so I also do not see any watering necessary.

Spruces have comparatively shallow roots, and generally grow much fuller if the top layer of soil is watered when dry, especially in the fall/early winter before the ground freezes. This year, the northeastern US had a wet fall. Waiting until the end of March was probably an estimation for when the ground would be drained and start drying out (you should never water soil when there's a frozen layer). Whenever that happens, you can water it.

It looks like your arborist knows what he's talking about. All of his instructions are good, for the conditions and situation you have. I'd just say that about using shredded leaves or light mulch in the backfill soil, if those are the materials you use, don't let pockets form, they will not only settle later, but could decompose improperly and slow root growth. I'd just sprinkle it in as the soil's going in, with no heavy layers. (I usually use near finished cold-compost for this).

For further reading on planting and care, see What is a good method for planting Ball and Burlap trees?

Answer 3

Sweet Sue! Now is not the time to be transplanting that tree into the garden. This is a bit more work and complicated than that help sheet. Yes, soak that tree. The burlap should be moist right now. You also have to acclimate this tree back to the cold temperatures. That will take at least 2 weeks.

Dig that hold wide and deep enough to accept the entire pot. To be transplanted next year. Get the heated christmas tree lights back on, primarily on the top of the roots, wrap entire tree in burlap.

After acclimating for 2 weeks, put pot and tree IN THE HOLE and as best you can dump soil over and around the pot. Mulch as well. Don't worry about soil/bark contact now. You could use straw or barf me bark to help. Then add the lights as close to the mulch and soil as possible without touching. Then add the burlap around the tree, snug but not too tightly...need air spaces to accumulate the heat of the lights and decomposing organic matter. Water this tree really well at the beginning of your acclimatization and that should be enough to hydrate your tree for surviving the winter...I'd do this in your tub, done it my tub. Grins.

When you transplant your tree after the soil has thawed take off ALL of the burlap and twine. Loosen any circling roots or make a few slices into the roots with a knife. If there is a metal root ball support leave that but ALL of the burlap comes off. Make sure the root ball sits on undisturbed soil so it doesn't sink any deeper.

These trees are meant to die, sadly. Hey I know the thinking from the other side of this equation. Where do you think I get my snarl? All about money. Did you acclimate this guy before you brought him inside? If not he'll be stressed and all the more importance to truly do a great job acclimating back out of doors. 2 hours for 2 days, 3 hours for 3 days, 4 hours for 4 days, etc. Would be nice to have this tree and pot on wheels. I know you've seen Christmas trees still green by spring cut and thrown out. They weren't alive alive with roots and hope to continue.

Make note; that tree was grown in clay in the nursery to keep a tight rooted root ball. Also is great for weight and stability. Clay to clay is perfect. If you go and try to 'improve' the soil in that hole you will be ruining this tree's chances. Clay to clay is very good. Clay is a good soil just need to know how to manage it. But to put a clay root ball into a sandy soil/different soil, the water when watered will skirt right over that clay and into the easy to drain pumice, sand, unnatural soil. This tree is a perfect size and has great chances to survive. Do not allow that tree to stay out side with freezing temperatures or the cold will kill your roots. During acclimation, burlap and christmas light that pot when the time comes to spend longer out of doors during the freezing. It is really a headache that they NEVER explain so that you will fail and have to try again next year. But this should help to ensure your tree lives. Hopefully, this location has lots of light...and watering once transplanted can be augmented with pvc pipe drilled with holes, mycorrhizae. Hold off on fertilizer until summer. Even then be frugal. Expect lots of needle loss...that burlap as dry as it is is worrisome. Soak these roots. Remember the root ball is clay and will have a hard time absorbing water if this tree hasn't been watered for awhile during its stink in a dry, warm atmosphere. TUB WORKS WELL.

Answer 4

In preparation for removal, the tree roots are watered so that the roots can be removed with the soil clumped around them minimizing damage to the roots. They are then wrapped in burlap. If not planted immediately, the root ball is kept covered to prevent sun and wind damage. Freezing should not damage it.

It will need to be regularly watered while enduring inside temperatures. But once you take your tree outside and plant it in winter, the tree will go dormant in the sub zero temperatures. And once it's dormant you don't need to water it.

The needles of evergreens are covered with a heavy wax coating to help prevent moisture loss, and the fluids inside the cells contain substances resistant to freezing, essentially evergreen antifreeze. Evergreens shut down for winter dormancy but continue most basic metabolic functions; the plants super-cool. Water in the cells is chemically maintained in a liquid state below 32 degrees F. (1)

Any moisture lost in spite of leaf adaptations can be replaced from the moisture in the ground that comes with winter weather.

Once spring appears, and the tree wakes again, then you need to start regularly watering it depending on the ground conditions.

1 - Sleep cycle of trees