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13 year old Autumn Blaze Maple problem #133480 - Ask Extension


13 year old Autumn Blaze Maple problem #133480

Asked June 11, 2013, 11:27 AM EDT

We planted 2 autumn blaze maples 13 years ago in our in front (south side) and one in back( north side). Both had gotten taller than our 2 story house. For the past 3 years, the one in the back yard started developing yellow leaves and did not come back at all this spring. The maple in the front is starting to show the same signs....sounds like the iron chlorosis your website talks about.

1) Is there ANYTHING we can do to help this beautiful tree survive/get better? Should we use a certain weed n feed on the lawn around it?

2) Is it possible to hire someone there to come look at it and give us suggestions?

3) What would YOU do if this tree were the glory of YOUR front yard?

Thank you for any help you can provide!

Jefferson County Colorado

Expert Response

first some background info....
25 years ago it was thought that 'Autumn Blaze', a hybrid of silver maple and red maple, would be a good replacement tree for silver maple, which often develops iron chlorosis in our alkaline, high-lime soils.   It is now proving to be just as prone to iron chlorosis as silver or red maple is locally.
Iron chlorosis (the "plant equivalent" of anemia) is the result when a plant cannot take up sufficient iron from the soil.  In local alkaline (high pH), high-lime soils there may be plenty of iron but it in a form not usable by some plants.  Plants must have iron to manufacture chlorophyll, the green, photosynthetically active pigment in leaves.  Your maples are not taking up enough iron to make chlorophyll, so leaves yellow and the tree declines (like your backyard maple) because it isn't making enough photosynthetic foods for itself.

Note that your front yard tree is more yellow on the side where roots are nearer concrete (alkaline) and where soils are compacted, which exacerbates iron chlorosis.

1) Is there ANYTHING we can do to help this beautiful tree survive/get better?
Yes - iron injections into the trunk (tree service), drill holes into trunk and "implant" iron capsules or iron citrate (tree service), use of iron sucrate or chelated iron products in the soil, spraying leaves with iron compounds (messy, stains sidewalks, more difficult as trees grow).  You can get much more detail and benefits/downsides of each of these and other treatment options at

Should we use a certain weed n feed on the lawn around it?
No... herbicides could injure your tree.   Fertilizer alone would stimulate new growth which won't be able to make enough chlorophyll

2) Is it possible to hire someone there to come look at it and give us suggestions?
Yes, Google American Society of Consulting Arborists or contact CSU Extension in Jeffco at 303.271-6620.  Both will charge a fee for a site visit. 
3) What would YOU do if this tree were the glory of YOUR front yard?
I wouldn't plant one, but if I inherited it in the landscape of a new home (the actual case for me) I would get a soil test done.  Soil pH above 7.6 and high-lime would suggest the iron chlorosis is going to be a long-term, ongoing problem, so I'd look at replacing the Autumn Blaze with a tree less prone to iron chlorosis.  In the interim I'd give the tree iron chelates in the soil and/or iron injections in the trunk.

Robert Cox Replied June 11, 2013, 3:38 PM EDT
Thank you very much, Robert!

I remember when we bought the tree at the nursery 13 years ago, the salesperson directed us away from the silver maple for that reason, and told us that the Autumn Blaze was developed to not have that problem. Sigh. What a waste. And they STILL sell these Autumn Blaze trees in nurseries in CO and of course, now that we have this tree with this problem, I notice them all over town with the yellowing leaves.

What success rate does the iron injections have? We will most likely look into this option.

And for the lawn fertilizer conversation above, we have to use a weed and feed on the front lawn; do they make it with iron/more iron in it-would that be helpful?Should we consider taking up the sidewalk where the tree is yellowing and spraying iron in that area?

And one more question, please: if we DO end up replacing this maple, what kind of deciduous shade tree do you reccomend we replace it with in this picky CO soil?  :)

Thank you!
The Question Asker Replied June 12, 2013, 9:33 AM EDT
It was hoped that Autumn Blaze would not have the same chlorosis problem.

Iron injections if done correctly are pretty effective, but need to be repeated annually or maybe every other spring.
Sequestrene 138 (iron chelate) is rooting area soil is effective, but messy and expensive.

Ideally, spot-spray weeds with a separate weed-killer (herbicide) rather than using a combination herbicide plus fertilizer ("weed-n-feed").   Herbicides in
weed - n - feeds can and have/may cause injury to trees with roots in treated areas.
Using iron fertilizers is mostly ineffective, as the iron is readily converted in our alkaline soils to a form that is less/not usable by some plants.

No, don't remove sidewalk to put iron in that area.   The benefits will be FAR outweighed by the trouble and expense of removing sidewalk.

How about a Greenspire linden?  A few aphid problems but no chlorosis.  Any tree replacement will have its own set of potential problems, so it that sense you'd be trading iron chlorosis for another potential problem.     No tree is perfect....
See also:  Note third entry page 2 Autumn Blaze maple
Robert Cox Replied June 12, 2013, 6:30 PM EDT

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