Notes on planting a pot-bound tree

 

The root-ball of the 12' tall sycamore tree I planted yesterday

A close-up showing how the roots were running around the inside of the pot. This condition is sometimes called "being pot-bound".

At the risk of spreading what might be controversial ideas, I follow the practice of making four vertical slashes to cut the roots that were running around the inside of the pot like so many NASCAR racers.

Hairspring

My thinking is that if a root starts out on one side of the tree and then travels 270 degrees before striking out radially, then that root will not be capable of stabilizing the tree in high winds. Rather, it is better if the roots' architecture have them strike out radially without first winding around the stem like a hairspring.

I have also heard arguments about the roots "strangling" each other but reject that thinking because roots happily graft when they cross.

The topsoil was deep. The loam leaned slightly toward "silt-clay". The sycamore tree should be very happy there. I staked it to reduce wind-whip while the roots settle in and make themselves at home.

Fertilizing late in the season

The conventional mental-model for trees hardening-off to survive the winter cold is that they accumulate carbohydrates in their buds and bark. In coordination with partial cellular dehydration, carbohydrates form a gel within and between the cells that inhibit the growth of needle-sharp frost crystals that puncture cell-walls.

The plant must execute a precarious balancing act because there are several biological functions that demand carbohydrates, which left in short supply will cause parts of the tree to die.

Ripening fruit is a huge demand. That is why nearly all super-hardy fruit trees ripen their fruit early. The carbohydrates that are created by photosynthesis after fruit drop is available to "harden off" the tree.

Rapidly growing shoots are also net consumers of carbohydrates. That is why it is unwise to use a heavy hand when fertilizing trees late in the growing season. The flush of growth sucks down the tree's supply of carbohydrates and increases the risk of it not being able to survive the winter.

Trees with genetics from more northern and higher elevation sources are less likely to push another flush of growth late in the season even when fertilized. Trees with genetics from warmer sources are more likely. That is why timber companies always include some seedlings from 200 miles to 400 miles farther south than the planting site; one more flush of growth per year might mean 50% more wood volume per year of growth.

Because of that, I didn't fertilize the sycamore tree beyond the three bags of composted cow manure I top-dressed the site with.