Tree depth help

[mjenkins]

Hello tree wizards!

A few years ago I received some great help here, it turned out I damaged a tree pretty badly by planting it too deep. I'm here to make sure I don't make the same mistake!

2 years ago I planted a Japanese Zelkova using a rootmaker knitted bag with the intention of moving it. Today is that day, I took a few pictures, I'm hoping your expert eyes can help me out. Is this tree at the correct depth? I am having trouble being confident in this because of how thick of a layer my zoysia lawn is. If it is good, about how much mulch should I add?

Thanks for reading!

 

[BC WetCoast]

You're good with the depth.
As far as mulch, when I plant I make a toroid. A very thin layer next to the tree stem (thick enough to hide the soil) and then a berm of mulch at the edge of the root mass. When you water, the water will tend to stay within the root zone rather than run off the edge of the mulch. The mulch when it dries becomes a little hydrophobic and can shed water.

 

[Del_]

BC Wetcoast may well be right but some things to consider are:

Did you loosen up the soil in the bottom of the hole?
If you did then there is going to be settlement occurring and you've planted it too deeply.

Planting on a mound is way better than planting too deeply.

I think you may be an inch or two too deep.

Zoysia is a fierce competitor. Your tree needs a 3ft diameter circle cleared of all grass and over the years needs to be expanded to the expanding drip line, IMO.

Zoysia may be allelopathic.
https://en.wikipedia.org/wiki/Zoysia_matrella

 

[Jason Douglas]

Yep. Wider tree ring and hope bottom of the planting hole was undisturbed.

 

[ATH]

It is close...certainly closer than most of the landscapers around here get!

I know it is close because there is a flare. Without poking around a little, it is hard to say from those pics if it is just right or just a little deep. I suspect it is an inch or two deep... Moisten it up and pull a little more soil back to find where the roots are coming off of the trunk. You want that right at ground level.

For example...below is a tree I planted:

The black line is where the soil was when I got it from the nursery.

The red line is similar to where I suspect yours is now.

The green line is correct planting depth.

 

[BC WetCoast]

I never think about soil settling, our soil is so coarse and drains well, we don't usually loosen the soil in the hole sides or bottom very much.

 

[Jason Douglas]

Alkaline calcareous poor draining clay here. It rules.

 

[Mk146]

As far as planting depth is concerned, you generally want the depth of your hole to be roughly 1-2 inches shallower than your root ball is tall. This will account for any soil settling; ideally the top of your root ball should be flush or slightly higher than the native soil. A few things can happen when you plant too deep, soil around the trunk retains excess moisture which can result in fungal infection and if the top of your root ball is covered with native soil, differences in soil texture can create irrigation issues. In poorly drained soils or soils with poor aeration and depending on how deep you plant, the tree may produce adventitious roots and the original root system may die back causing structural issues.

Organic mulches should be roughly 3-4 inches thick with a spacing around the trunk of 1-2 inches to avoid excess moisture accumulation.

It's also worth noting that recently planted root balls are going to need more frequent irrigation until the roots expand into the surrounding soil. Differences between soil texture of root balls and native soil create a soil interface which can significantly impact water movement. It's not uncommon for surrounding soil to "steal" moisture from the root ball; the root ball can be relatively dry even when surrounding soil is at normal field capacity. Be sure to water the root ball directly instead of the entire surrounding area to avoid unnecessary saturation.