London Plane not looking good...

Cycle Pilot · Aug 31, 2012

This is my first post on the forum so please bear with me. We recently purchased a home in a suburb of Sacramento. The previous owner neglected the landscaping for a while. Most of the trees look like they're doing ok except for our largest tree in the front yard. I did some research and have come to the conclusion that the tree is most likely a London Plane. Its leaves are ragged, brown, and some have white spots on them. The bark on the trunk and the branches is dry and breaking off. The tree gets plenty of water from the sprinklers. I'm posting a link at the bottom of this post to an album where I've taken a couple of pictures of the tree. I'm hoping all you tree experts out there might have an idea of what I'm dealing with. Thanks in advance! Feel free to leave comments in the photo album if you have questions about specific photos.

London Plane Photos Link

Raintree · Sep 1, 2012

Two things & a possible third.

- powdery mildew, the white film look on the new leaves. This late in the season IMHO not worth the treatments.

- Spider mites, can be a problem, populations can explode & get out of balance. Damage is worse when compounded by water stress. Most sprinklers don't meet a trees water requirements. Seek good advice from an Arborist to treat or not.

- Lace Bugs, a few of your leaves appeared to have yellow blotches, ask your Arborist to check for you.

Exfoliating bark & dry interior limbs are normal.

Cycle Pilot · Sep 1, 2012

Raintree said:
- powdery mildew, the white film look on the new leaves. This late in the season IMHO not worth the treatments.

So, when's the best time to treat for powdery mildew? Will the tree make it through the rainy season if we don't treat?

Raintree said:
- Spider mites, can be a problem, populations can explode & get out of balance. Damage is worse when compounded by water stress. Most sprinklers don't meet a trees water requirements. Seek good advice from an Arborist to treat or not.

Would we be able to see the spider mites? Or do you need a microscope? Do sprinklers give too much water or not enough? I have the sprinklers running for about 16 minutes total per day (two 8 minute runs).

Thanks again for all your help! I really appreciate it!

Urban Forester · Sep 3, 2012

None of the problems Raintree mentioned can cause terminal decline. Most insects and foliar pathogens rarely do. However, 16 minutes a day of water on a London plane could. Soil borne pathogens thrive in wet soil, and/or soil lacking in oxygen. 16 minutes a week is most likely adequate, unless you get very hot, windy conditions.

Ed Roland · Sep 3, 2012

Gary, i thought you were on vacation. What you doin online? :laugh:

OP, good call on the P. acerifolia. IMO, add a super hot summer to all the above and you might be getting close to a diagnosis. It is unusual for any one thing cause the mortality spiral, if thats what we have here. As Rain points out, late season issues w/ foliage is not of super concern (discalimer,tax, title, tags, batteries not included, et al, etc, etc).

Try Trees Are Good for optimum cultural practices. Avoid modern fertilizers and monitor this specimen. Post up some pics next season and lets see how she is fairing.

landscape doc · Sep 4, 2012

london planes - check out soil profile at dripline etc.

from pictures of tree, it looks great. PM in damp weather usually not a serious problem on vigorous tree.

post hole digger usefull
check for layered soil, clay - poor drainage. this could be a problem in the future