How to fend off early stage root rot?

June 17, 2018 3:37 PM

I've got a lilac tree in my backyard that isn't growing like it should.Mushrooms grow in clusters in that area if left unchecked. The area around it smells like mushrooms even when there aren't any. Digging around the tree, I found its root are waterlogged, which makes sense since this area of the yard gets pretty saturated. There are rotten bits of a long gone tree underground nearby. What is the best plan for what to do next?

The tree doesn't look sickly and its roots don't look rotten. So I think I got to the problem early. The tree grew well at our old home but stagnated when we moved it here to our new yard in this spot. I am afraid if I don't move it to somewhere less waterlogged, it will die. Is moving it at this point going to shock it and kill it? If moving it is okay, how much soil should I take with it. Should I use some kind of fungicide?

What do I do now?

I planted this tree in honor of my late father. I really want to save it.

posted by Comrade Doll to Home & Garden (11 answers total)

Soil aeration. Can be as simple as stabbing the soil in an annular ring around it with a garden fork. That’s the first-response emergency measure; longer term you will have to increase drainage somehow, or move it.

Drainage can be increase within simple trenches, French drains, soil amendment (e.g. sand, but also other inorganic matter). It’s a complex topic.

Moving it may be best, if you can move it to an area with better drainage and circulation, perhaps a bit more light. How long has it been since you moved it, and can you still move it?

On balance: fork it through the end of this season, move it in the fall after it’s gone dormant. Do not attempt to move it when it is already stressed and in high summer (assuming northern hemisphere? ps please everyone include rough geographic region for all plant quesitons, it always matters).
posted by SaltySalticid at 4:50 PM on June 17, 2018 [5 favorites]

Oh, and when moving, take as big of a root ball as you can manage. You don’t tell us much of a thing about the size (basal trunk area, height, diameter at breast height, any clue would help give a more explicit guideline)
posted by SaltySalticid at 4:52 PM on June 17, 2018 [1 favorite]

Response by poster: The tree is about six and a half or seven feet tall. The root ball is maybe 20-24" in diameter. The trunk is maybe only three and a half inches in diameter at the bottom.

I am in the greater Chicagoland area (US Midwest).
posted by Comrade Doll at 6:35 PM on June 17, 2018 [1 favorite]

As SaltySalticid says it's a complex topic.

How long has the tree been planted at your place?

If drainage is not an option moving is arguably the only option but it pays to do that in stages with a larger plant unless you have pots of money. Surrounding your lilac with thirsty plants is part of a solution to drain it.

I do not know anything of what grows well and is thirsty in Chicago but here is a good start https://www.chicagobotanic.org/conservation/rain_garden [link think not working for me] and look for Choose the best plants for the project . Call this an interim measure - also go to this page and look at Carex https://www.prairiemoon.com/seeds/native-grasses/

But if you were going to move it, the best option would be to lift it some inches to a foot and mound up earth to match the existing height of the earth

If you have time wrench the tree by cutting the roots a third to half way round the base as far from the trunk as you can this year. Next year do the second third or last half (if you have time or if tree is well rooted in take three years ).

Finally dig around and under tree, severing every little root (you want move to be as gentle as possible). Have a frame using e.g. three scaffold pips in a teepee form plus some kind of winch/tackle to lift it. then you can lift the tree and repack earth tightly underneath before you set it down again at it's new height. The forms a wide mound upto the trees - you should have a flat bit a yard across that gently tapers off to existing garden height.

Again it's complex, more like life-support than gardening
posted by unearthed at 12:58 AM on June 18, 2018 [1 favorite]

Another option is to air layer it, creating a largish clone that can be planted elsewhere. Then, even if you fail to keep the original alive, you’ll have a healthier, younger copy thriving in the new better location.

For me, this would keep the symbolic meaning intact.
posted by SaltySalticid at 7:27 AM on June 18, 2018 [1 favorite]

And if you want to just throw money at the problem of moving it, call around to tree companies in the fall, and ask if they have a tree spade suitable for moving a tree that size. It won’t be cheap, but they can do it with heavy
machinery in a few hours.
posted by SaltySalticid at 7:30 AM on June 18, 2018 [1 favorite]

Response by poster: The root ball is pretty small and the tree has only been in this spot for a little over a year. That's why I was thinking I could maybe get away with moving it. Now I'm working on a revised plan. I've dug out all of the rotten smelling soil from around it and I'm letting it air out for about a day. Then I'm going to replace all of the soil around it.

Planting thirsty plants around it makes a lot of sense. That and aerating a lot seems like a way to go until fall.

I notice no one is mentioning fungicide.
posted by Comrade Doll at 8:05 AM on June 18, 2018

Tree lilacs don't like their feet to be wet, so eventually your tree will be showing some distress. If you are able to dig it up but don't want to move it, another possibility is to elevate it somewhat by digging it up and adding a good deal of soil to the immediate vicinity - say, an 6 x 6 square foot area - and then replanting it in the mounded area. That would provide for better drainage. Another possibility would be to make a rain garden (a below-grade garden installed to capture runoff) nearby and install a drain pipe or a gravel-filled trench from the vicinity of the tree to the rain garden.

Fungicide is pointless; the issue is that the soil is too wet for the tree. Rot is the result. Treating the result doesn't get you anywhere, you need to improve the drainage or relocate the tree.
posted by Lunaloon at 8:36 AM on June 18, 2018

Response by poster: Sorry to keep replying. I know that is bad form.

But if the root ball is compact and moving it without trimming the roots or otherwise physically damaging the tree is possible, am I clear to move it now to a drier place? Or do I still have to wait for fall and for the tree to become dormant?

I just want to do whichever is better for the tree.
posted by Comrade Doll at 8:53 AM on June 18, 2018

Dormant and before bud-break is the best time.

But where these things are correct:
" if the root ball is compact and moving it without trimming the roots or otherwise physically damaging the tree is possible"

Then I have had success in (summertime in a NZ Mediterranean climate but touch and go, autumn in NZ sub-alpine zone - min 15 C winters and UK autumn). The trick is moving the plant g.e.n.t.l.y - movement damages the tiny roots that you can't see (this is about 99% of all the roots), and packing all voids with good earth, and making sure plant has regular water for two years afterwards.
posted by unearthed at 8:09 PM on June 18, 2018

Move it after it goes deciduous, if you can wait that long. I'm a horticulturalist who worked for years as a gardener and we would move established trees this size all the time, without worrying about dormancy. You may find it induces early dormancy; that's okay. It's also not a huge deal to root prune a tree as long as the mass of roots roughly equates with the canopy. If it's super soggy you're going to want to shimmy a tarp under the root ball to keep it intact when moving. At the very least, the suggestion to elevate it somewhat above the water table while remaining in the same spot is a good one.

Do not prune the canopy at all the following year, as more leaves helps with establishing root growth.
posted by oneirodynia at 1:19 PM on June 19, 2018