Very, very, very slow soil infiltration

[chrismar]

I have (had?) a river birch tree that I removed from one of my landscape beds to make way for a new red emperor japanese maple. For $hits and giggles I decided to fill up the hole with water to see how long it would take to drain to make sure I wouldn't eventually drown the roots of this new and expensive tree. I knew my soil was a poor drainer. I know it's clay(ish) based on the TEC of my soil test, but I didn't know it was this bad.

Pictures are worth a 1,000 words, right?

The hole was filled at 4:45p on Wednesday 10/19/2016. These pictures were taken at 10:15a this morning (10/21/2016). The hole is about 20-21 inches deep and 26-27 inches across. I filled it with 13-14 inches of water. 8 or so inches remain ~41 hours later. We haven't gotten any rain since filling the hole with water.





What can I do about this? I was already planning on elevating the tree's root ball 6 inches out of the ground. Should I go more? Will BLSC help? I've read to NOT amend the backfilled soil with compost as it can create even worse drainage problems, so I won't be doing that.

The tree is being delivered sometime next week, so I don't have much time!

[MorpheusPA]

Do you know if you have a clay lens underneath your top soil? That can form an almost impenetrable barrier to water (as can solid rock).

BLSC is certainly worth a try, but it'll work over time, not all at once. Other than that, I'd be very, very tempted to break the rule in this instance and use 2-3% compost in the mix of the hole. Or, not very much, but enough to sop up at least some water.

[chrismar]

Do you know if you have a clay lens underneath your top soil? That can form an almost impenetrable barrier to water (as can solid rock).

BLSC is certainly worth a try, but it'll work over time, not all at once. Other than that, I'd be very, very tempted to break the rule in this instance and use 2-3% compost in the mix of the hole. Or, not very much, but enough to sop up at least some water.

I don't know if there's a clay lens. I do know that this area is known for its shale. Could shale have a similar effect?

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[TimmyG]

One possible solution:
http://aroundtheyard.com/soil/questions ... ml#p258747

The river birch may have liked it wet, but that Emperor japanese maple won't tolerate constantly wet feet. Also consider mounding high and planting above grade rather than planting it in a clay bowl.

[chrismar]

One possible solution:
http://aroundtheyard.com/soil/questions ... ml#p258747

The river birch may have liked it wet, but that Emperor japanese maple won't tolerate constantly wet feet. Also consider mounding high and planting above grade rather than planting it in a clay bowl.

The river birch wasn't too happy in that spot either. That's probably why the Mrs wanted to swap it out, because it was darn ugly.

I'm not sure that there's good soil underneath. I'm afraid I'll hit the shale pretty quickly and, well, that would pretty much be the end of that exercise.

I was prepared to have it sitting 6, or maybe even 8" above grade. Won't it look really weird if it's more?

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[andy10917]

If your tree is expensive, I'd talk to an arborist or county extension service. I know of very few (actually none, but I'll leave the window open) knowledgeable tree folks that think that mounding soil is a good idea. It exposes more roots to more extreme temperatures (the mound is more exposed to air temperatures in a larger area), it doesn't work at all as the tree roots spread with tree growth, etc. I know the Bridgewater area (HQ in Warren and have worked in Bedminster), and I wouldn't think that an above-grade installation is advisable.

[chrismar]

If your tree is expensive, I'd talk to an arborist or county extension service. I know of very few (actually none, but I'll leave the window open) knowledgeable tree folks that think that mounding soil is a good idea. It exposes more roots to more extreme temperatures (the mound is more exposed to air temperatures in a larger area), it doesn't work at all as the tree roots spread with tree growth, etc. I know the Bridgewater area (HQ in Warren and have worked in Bedminster), and I wouldn't think that an above-grade installation is advisable.

Ok, thanks. I think the guy I bought the tree from is an arborist. I can ask him what he thinks.

I know it's pretty common, at least it appears to be common around here, to have the root ball stick up a few inches above grade to help in these sort of situations. It might not be enough in my case I guess.

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[GeorgiaDad]

If you have a piece of pipe, now would be a good time to experiment. Drive/tap it down in the hole. If you hit rock, you'll know it. If you hit clay, some should come back up in the pipe.

[chrismar]

If you have a piece of pipe, now would be a good time to experiment. Drive/tap it down in the hole. If you hit rock, you'll know it. If you hit clay, some should come back up in the pipe.

What kind of pipe are we talking about here? I have 1/2", 3/4" and 1.5" pvc on hand, but that's probably not rigid enough, is it?

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[Spammage]

PVC probably will break before it tells you anything. Steel rebar, steel pipe, a 2ft screwdriver, pry bar - there are a lot of things you can try. Depending on the area and if this is really an expensive tree, why not just dig out a few yards of the crappy soil and have some new soil brought in that will drain better. There is only one time to do this right, and like others have said, I would be against having the root ball above the ground.

[andy10917]

why not just dig out a few yards of the crappy soil and have some new soil brought in that will drain better.

The question becomes "drain to where?". If it doesn't drain, it makes little difference whether it's a sink or a bathtub -- it does not drain. Clay or shale, an outlet is needed or it's game-over.

[TimmyG]

Yeah, if you can't prove that you can break through an impermeable layer, no size hole is going to help. And when I suggested mounding, I wasn't thinking a few inches and a few buckets of soil; I'm talking about creating a berm with yards of soil, essentially raising the grade all around the tree. It's a last resort solution when you're committed to putting a specimen where it would otherwise fail if planted at grade. It's how people successfully grow rhodos in heavy clay soil, rhodos being intolerant to overwatering.

[chrismar]

I wasn't thinking a few inches and a few buckets of soil; I'm talking about creating a berm with yards of soil, essentially raising the grade all around the tree.

This is what I'm thinking too. I'm going to contact one of the tree professors at Rutgers to see if they'll give me some ideas as well.

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[andy10917]

It might work on rhodos in the South, but those aren't going to face months of frozen soil. And raising the soil over a large area just makes a deeper bathtub - it doesn't change the problem.

It sounds like Chrismar really wants this to work - and it's probably going to take an arborist's skill to make it work.

[chrismar]

Alrighty, just fired off nearly a dozen emails to various arborists, master gardeners, extension officers, "certified nj tree experts" and Rutgers professors. We'll see if anyone writes or calls me back.

[Spammage]

why not just dig out a few yards of the crappy soil and have some new soil brought in that will drain better.

The question becomes "drain to where?". If it doesn't drain, it makes little difference whether it's a sink or a bathtub -- it does not drain. Clay or shale, an outlet is needed or it's game-over.

Fair enough - but I wasn't talking about a bathtub. I was thinking more small pool - 8-10+ yards. While digging it out you might even remove the layer that is causing issues if it indeed is a layer.

[andy10917]

8-10 yards? Really? You win - I'd stop at asking an arborist or possibly fracking the tub with small tactical nukes.

[Spammage]

Ok - I'll bite. You thinking to large (6'x6'x6'=8cu yards) or not enough to justify the effort?

[LoneRanger]

^ Time to rent a backhoe.

[Kmartel]

What is the grade of the area?? Is is possible to install a drainage pipe under the tree and trench it to daylight?? You do not want to plant that tree in the current situation as it is sure to struggle.


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