In the Garden: “The Best Time to Plant a Tree…


…was twenty years ago. The second best time is now”.

Chinese Proverb 

Sage advice. I’m going to assume that you missed the twenty-years-ago deadline, so we’re indeed talking about now. Or the coming weekend, perhaps.

Buying The Tree 

Now is the best time to buy a tree as well, since deciduous species have gone dormant. Avoid the temptation to buy the biggest tree you can find. First, it will be much more difficult to handle and will require a larger planting hole. Second, it is not likely to become established as quickly as a smaller tree. The smaller tree will probably catch up with its bigger brother in a few years. Once you get your tree home, if you’re not planting it immediately, put it in a shady location and water it once a day.

Digging The Hole

You can find a lot of rehashed wisdom on the size of the planting hole, pretty much boiling down to “bigger is better.” Many sources recommend a hole that is three times the diameter of the plant’s container. That said, one study I read said there was no significant relationship between size of planting hole and the tree’s establishment. (They did state that the size of the tree is significant. In temperate climates, generally allow one year per inch of the tree’s diameter for establishment; i.e. a two-inch diameter tree should be pretty well established in two years.) So, no need to overdo it; a planting hole that is 2X the diameter of the root ball (or container) should be adequate.

If you’re fussy like me, you might want to remove the turf from the planting hole area before digging. That way you don’t have grass popping up in your backfill later on. For the actual digging, I sometimes use my little Mantis tiller to break up the soil if I’m digging a very big hole. The downside: you then have to go back and use a shovel to remove the soil from the hole. Dealing with the backfill will be easier if you pile it onto a tarp, a large piece of cardboard, or even into a wheelbarrow.

The depth of the hole is more significant then the diameter. The top of the root ball should be no lower than the soil grade. In fact, with our clay soils, it’s not a bad idea to have the root ball sitting one or two inches above grade. If you get overly enthusiastic and make the hole too deep, put some backfill in and be sure to tamp it down well. Otherwise, the tree will settle too deeply into the hole and possibly drown. To give the tree’s roots a better chance of penetrating the wall at the edge of the hole, score the sides a bit with a digging fork or cultivator.

Removing The Tree From The Container

This can be a tricky process. One big no-no: don’t attempt to yank it out by grabbing the trunk. Instead, lay the tree on the ground and gently tug at the container while another person grasps the trunk. If the container doesn’t come off readily, cut through it with your pruners or a sharp knife. One or two cuts should allow you to peel the container away from the root ball.

At this point you may be confronted with a mass of roots circling around the edge of the root ball and a tight mat of roots at the base. If not dealt with, these roots are not likely to spread out radially. Instead, they will circle the plant, at the very least restricting its growth, and possibly killing it. If practical, tease the roots apart with your fingers. If this isn’t working, take a knife and make four cuts vertically down the root ball. Losing some roots or soil in the process is not a big deal.

Placing The Tree And Filling In The Hole 

Make sure the tree is standing straight in the hole. This is your one and only chance to do this. A tree planted with a slant will straighten up on the new growth at the top, but the original slant of the trunk will always be there. Spread the roots straight out from the tree as much as possible. To keep them heading in the right direction, try weighing them down with some dirt or a small stone.

And what should you be putting back in the hole? Super-Duper Topsoil with Fertilizer you bought at the garden center? Absolutely not. This can lead to “clay-pot syndrome,” where water collects in the hole and rots the roots. Just replace the soil you took out, breaking up large dirt clods and removing big rocks. If you have some compost lying about, add a little bit to your backfill, but no more than 10 percent of your mix. As you fill in the hole, tamp down the soil with your hands or gently with your feet. You need to get rid of air pockets, but you don’t want to make a brick from the clay. If you planted your tree a couple of inches high, make sure the backfill meets the edge of the root ball, then tapers gently away.

Mulching And Watering 

Cover the entire planting area with an organic mulch to a depth of three inches, but do not put any mulch within four inches of the tree trunk. Water thoroughly and deeply immediately after planting, then once or twice a week thereafter for the next year.

Staking… Or Not

Staking trees is not always necessary. A deciduous tree with a heavy root ball should be pretty stable, especially in the winter when the leaves are off. An evergreen tree, or one with a smallish root ball, would be more liable to tip. If you want to play it safe, put in three stakes, making sure that you put the rope/wire through a short length of old garden hose to avoid chafing. Don’t stake too tightly. The trunk should sway a bit in order to encourage stronger growth. And stakes should be removed after two years.


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