User avatar
djlen
Green Thumb
Posts: 660
Joined: Thu Oct 01, 2009 8:37 pm
Location: Just East of Zone 7a

Larch Trees Yellowing

I have a bunch of deciduous Larch trees growing in pots and they do the same thing every year. They start off very vigorously after I repot them into new soil and then as the season progresses the needles begin to yellow from the inside out and drop.
I'm pretty sure it's a deficiency in fertilizer but not positive because it's the same pattern every year. If I let them continue to yellow it will sometimes kill some of them. I have been separating them in order to arrest possible disease but I don't know if that't the issue or not.
These trees are very, very vigorous and I think they need additional feritilization and of the acid variety.
If anyone has any knowledge about them that would help here I'd appreciate it.

valley
Greener Thumb
Posts: 1335
Joined: Tue Mar 06, 2012 1:25 am
Location: ranches in sierra nevada mountains California & Navada high desert

Is this yellowing all over the tree, mostly on lower branches, or mostly on top of the tree?

User avatar
djlen
Green Thumb
Posts: 660
Joined: Thu Oct 01, 2009 8:37 pm
Location: Just East of Zone 7a

It starts in the lower branches, mostly on the inner part of the tree but works it's
way outward and up the tree over time. All needles affected fall and if I let it go it
could and has killed trees.
It does not seem to happen to single trees but when I have a group planted together
it's almost inevitable that it will occur.
We have had a really wet Spring and early Summer and the Larches were all doing great
but with a short dry spell (during which I watered) the brown needles started showing up.
I think that it's just a coincidence that it happened then because it seems to happen at this
time every Summer regardless. Thought it might be dry soil as mentioned above or lack
of nutrients because these trees are very, very vigorous, so I fed them to try to check it.
But to no avail. They continue to brown.
Meanwhile I have a single specimen in a separate pot that shows no signs of browning.
Suggestions or possible fixes???

tomc
Super Green Thumb
Posts: 2661
Joined: Sun Apr 10, 2011 2:52 am
Location: SE-OH USA Zone 6-A

If your living on the southern frontier for larch (and you might be) anthracnose from dry soil would be my guess.

A barrier between your tree baby(s) and dusty roads--plowed fields may help.

User avatar
djlen
Green Thumb
Posts: 660
Joined: Thu Oct 01, 2009 8:37 pm
Location: Just East of Zone 7a

Is there a treatment for this disease? Is it a Canker?

I've looked and cannot find any mention of it in connection
with Larch. I did see a picture of Pitch Pine affected by it and it
looks very similar to what I've got.

tomc
Super Green Thumb
Posts: 2661
Joined: Sun Apr 10, 2011 2:52 am
Location: SE-OH USA Zone 6-A

This is by anecdote only but was told to me by another hobbyist and it has worked for me. The more dust his trees got (rather than mere heat) on them the more they yellowed.

is it science? Myth? Beats me. The more dust my larch get the faster they yellow...

User avatar
djlen
Green Thumb
Posts: 660
Joined: Thu Oct 01, 2009 8:37 pm
Location: Just East of Zone 7a

It's hot and humid here with lots of rain. No dust at all. I am
trying to keep them moist and fed them last week. Don't like to feed
in the heat but they had grown so fast in the Spring I thought the yellowing
might be due to malnurishment.
Lots of needles on the soil. I'm cleaning it up and keeping the moisture
level high. Don't know what else to do.



Return to “Trees, Shrubs, and Hedges”