Fertilizer Burn--possible repot

[pwk5017]

Ugh, I hate to even ask this, but I feel a little desparate. I ran out of my usual lesco fertilizer a month or so ago, and purchased a cheap lowes 10-10-10 fertilizer to finish the last 35+/- developing trees. Well, first to exhibit issues were my 2-3 year old pines. I had a thread on them where the base of the needle blackened, and eventually death followed. I panicked thinking it was a blight/fungus/whatever, but pretty soon I realized only the lowes fertilizer pines were affected. Now, I have had a few japanese maples died off. Once again, young stuff, like 3-4 years old. Now, my older japanese maples are starting to exhibit leaf burn at the tips of the older leaves. Surely, these will die if I do nothing. Perhaps, it is already too late. Something is clearly up with this fertilizer from lowes. I didnt apply it very heavily, but it is scorching EVERYTHING. I am going to be upset about the older maples if they die, so I want to do whatever is possible to save them. Should I repot them, bareroot them, or leave them in their grow boxes in the taunted soil and partially defoliate them to lighten the load on the roots?Right now, I think I am going to bareroot, and place in maximum shade for the rest of august. Potentially defoliate quite a bit to compensate for the roots being compromised at the moment. Has anyone had to deal with this situation before? Any suggestions? These are 5-6' maples with 2" trunks. Very vigorous growers up to this point.

Patrick

 

[JudyB]

Is it a granular or liquid fert? If liquid, then flushing it out with massive amounts of water should rid the tree of any excess. If granular, then I would suggest scraping the top soil off, and putting on fresh soil.

I would never repot a weakened tree, UNLESS it was root rot, which doesn't sound like the case. I can't imagine what caused your problem with this fert, unless it is somehow a bad batch, or you mixed it incorrectly by accident. 10-10-10 is a balanced fert, I don't understand why it would give you burn.

I would also not defoliate, the tree's are weak right now, they'll need every resource they have to build up for winter. Don't bareroot them either, that would probably put the nails in the box.

Are you SURE it is the fert?

 

[coh]

I agree with Judy (and this is what Brent Walston suggested when I had some fertilizer burn symptoms on some plants I got from him). If it was a liquid, heavily water/leach the soil (he advised letting water run on the plant for an hour, don't know if you need that much time). If it was granular, I like the idea of removing and replacing the top soil layer, followed by leaching with water.

Please tell us exactly what kind of fertilizer it was (brand name, type of packaging, etc). It could have had a heavy salt load, or been contaminated in some way. If you have some spare plants you might want to do a careful controlled test to see if you can reproduce the results. Could even get some cheap annuals from Lowes to test it.

Chris

 

[MrFancyPlants]

I've over fertilized a ficus earlier this summer and it defoliated it's self within a couple days. I flushed w/ water and it has sprung back since then. I think the sensitive leaf drop of ficus worked great as a survival mechanism in this case.
I also think that Judy's advice is sound.

 

[pwk5017]

It is a granular 10-10-10 fertilizer.

I cannot say for sure it is the fertilizer, but I have had 30+ plants die or decline in the last 2 weeks, and they all have the fertilizer application in common. Its across multiple species and since I ran out of the regular fertilizer 2/3rds of the way through my developing stock, its pretty clear what the issue is here. I have one JBP thriving next to one that is brown. I am afraid to just scrape off the top layer, because I believe the fertilizer has penetrated into the soil. Its no longer "just on top". It has sort of dissolved and im sure its present throughout the soil column. My maples are in a slightly heavier soil mix of about 50:50 bark and turface/pumice. For whatever reason, this heavier organic mix has buffered them against the fertilizer. The pines were the first to go. It was perhaps instantaneous. I think 12-24 hours from application to visible signs of death. They were planted in 100% inorganic mixes and pond baskets. I just dont think leaving these maples in the tainted soil is going to cut it. Obviously repotting in august is just about as bad as it gets, but im hoping with the right after care they can bounce back.

 

[Dav4]

Picures would be helpful here...this is the time of year maple leaves begin to look a bit ratty, and I'm guessing you havn't applied any more of the offending fert in a while, so....

 

[coh]

Is it Lowes brand or some other brand they carry?

I might unpot one of the trees to look at the roots. If the roots look OK, I'd just go ahead and heavily flush the others. If the roots look damaged...then maybe repotting would be the way to go. Not sure.

Chris

 

[pwk5017]

I will take pics when I get home from work. The leaf burn isnt alarming at this point, but I have been watching these trees like a hawk ever since I had the suspicion that the fertilizer was killing things. The fertilizer was sooooooooooooo light on the main tree in question here. It was the last tree I got to with the normal lesco fertilizer, so I just sprinkled maybe a tablespoon of the new fertilizer on this tree. Its in a grow box thats 2'x2'x6". I will inspect the bag of fertilier when I get home as well. The flushing might be the best idea. Anyways, I think a alot of questions need answered before I take action. I just discovered the issue last night, and I have been panicking about it all day hahaha. Its gonna be hard to lose a tree I have been growing since I was 19. Not cool to waste 5+ years on something.

 

[Dav4]

The leaf burn isnt alarming at this point,

The fertilizer was sooooooooooooo light on the main tree in question here. It was the last tree I got to with the normal lesco fertilizer, so I just sprinkled maybe a tablespoon of the new fertilizer on this tree. Its in a grow box thats 2'x2'x6".

Focus on these. You didn't apply much and you don't think the leafburn is that bad. I'd bet, with all the rain you/we've had this summer along with your regular watering, that there isn't any of that fert left in the substrate. By the way, have you been feeding with other ferts?

 

[pwk5017]

I investigated the situation further when I got home. Scraped away the top half inch of soil, and was finding nothing but black and rotten roots. I was pretty disheartened, but I continued on. I wanted to see the extent of the damage, and figured the only way this tree had a shot of recovering was to cut away the gunk, and remove the toxicity that the fertilizer added to the medium.I ended up removing 50-60% of the soil mass. I would say about that much of the root system was complete trash. I then flushed the remaining medium for 10+/- minutes. I was considering moving the tree to a very shady spot in the yard, but the grow box was affixed to the ground. Im pretty sure the only saving grace for this tree is the fact that part of its root system is in the ground and was unaffected by the fertilizer. As I was cutting away the rotten roots, I did notice very small white root tips emerging from some of the thicker roots. The tree is definitely attempting to revive itself. I backfilled the container with 50:50 pumice and turface. Im hoping the increased porosity and airflow is going to nurture the roots back to life. Finally, I put together some haphazard shade structure made of fiberglass window screen. I dont have shade cloth, so this will have to do. I think window screen is like 70% shade cloth. As the pictures show, the foliage isnt a complete wreck. It has more than enough food producing mass to replace the roots. I just need to keep it from desiccating before those roots are able to regenerate. I hope the shade helps. The interior leaves are devoid of leaf burn. Its the exterior ones that are showing signs of distress.

 

[pwk5017]

Crap picture but you can see the white root tips emerging through the bottom of the flat.

Anything else I should do at this point? I plan on watching the moisture content of the soil like crazy, and maybe giving the tree a hug. Any guesses at success rate here? 25% chance of survival?

 

[dkraft81]

I feel your pain. I ended up having to repot a maple today. We have had a way wetter summer than normal, and I had a pot that wasnt draining great. I had no idea it was holding water until I started loosing leaves quick. When I moved the pot water was running out.

 

[davetree]

Black rotten roots are probably not caused by your fertilizer. Check your soil for proper drainage. Your grow boxes look pretty big for the trees in them. You may have over-potted and they are just holding too much water.

 

[JudyB]

I agree with Davetree, roots don't usually melt into black goo overnight. And to be honest, the leaves on that tree don't look as bad as I expected from your description. Looks better than one of mine at this point... It's been a tough year for leaf health.

I don't think you need to do anything, except to be careful how much water/sun they get, looks like it isn't in any danger to me.