Magnolia Grandiflora Leaves
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sunpath8
Location: Western Washington
Posted: May-11-2005 at 12:18pm
We have a Magnolia grandiflora (Southern Magnolia) that is looking pretty distressed. I searched the forums for magnolia and came up with nothing (maybe I'm doing it wrong?). Anyway, the leaves are looking really droopy and have spots and discoloration all over them.
I googled this species and found that a common ailment is leaf spot, though I'm not sure I'm identifying it correctly. I also noticed that there are a lot of new leaves getting ready to open up. Maybe the old leaves are just drooping and falling to prepare for the new leaves? Seems like that didn't happen last year, but that could be what's going on. The tree is in full sun with well-drained soil. The change has been pretty sudden - a week an a half ago everything looked peachy.
Any thoughts about what might be going on and/or how to help the tree would be much aprpeciated!
Lisa A
Location: Oregon, Greater Portland Metro
Posted: May-11-2005 at 1:29pm
Are you noticing the problem only with the oldest leaves? If so, it is possible that this is normal leaf drop. What proportion of the tree's leaves are looking this way? How long ago was it planted?
While I wait for your answers, I'll look through my resources to see what else might be going on.
sunpath8
Location: Western Washington
Posted: May-11-2005 at 2:00pm
We bought and planted the tree last March. I would guesstimate 60 to 80 percent of the leaves are looking droopy and spotty. I'll try and take a picture of it tonight to post so you can see more clearly. I'm keeping my fingers crossed for normal leaf-drop
JeanneK
Location: Oregon, Greater Portland Metro
Posted: May-11-2005 at 2:16pm
Leaf drop is normal for a magnolia grandiflora but to have 60-80% looking spotty and droopy is not normal. Sounds like a disease of some kind. Hopefully, Lisa can come up with some info for you.
Jeanne
Lisa A
Location: Oregon, Greater Portland Metro
Posted: May-12-2005 at 10:16am
Sorry, sunpath8, but it doesn't sound like normal leaf drop. There are a number of things that are possible but you will need to do a little more sleuthing to determine which one is causing your magnolia problems. Start by looking at all parts of your tree. Dig gently around the roots, check the bark and look closely at the leaves and note anything that doesn't look normal or healthy.
Are there any symptoms on the trunk? Magnolias can sometimes experience wetwood or slime flux, which is a bacterial infection. Usually, it enteres the tree through an injury to the bark. The foul-smelling fluid builds up inside the tree and oozes out, leaving discolored, water-soaked areas on the trunk or branches. It will cause foliage wilt and branch die-back. There is no cure but if the tree is kept healthy, the disease may slow or stop its progression.
Magnolias are also susceptible to verticillium wilt and bacterial blight.
Verticillium can cause sudden dieback of branches, yellowing and early defoliation. Discoloration or streaks of darker color in the sapwood (you need to cut branches to see it) are a telltale sign, but it doesn't always show up, especially when the disease is young. This is a soil-borne fungus for which there is no cure. Treatment is either removal and replanting with a resistant tree or keeping your tree as healthy as possible to slow the disease's progress.
Bacterial blight loves cool, wet spring weather (gee, just what we've been having). New shoots wilt and die back. You might also see dark, irregular spots on the leaves and on the flowers.
There's also Phytophthora canker. Check the trunk's base for sunken, water-soaked, brown or blackish cankers.
And lastly, it could simply be something cultural going on and not a disease. This is usually an easier fix. A drier than normal winter, girdled or damaged tree roots are just a few other things to consider and check. If the 60-80% of the leaves affected are primarily older leaves, it could be a stress reaction to any of the less-than-prime cultural conditions.
If you rule out cultural problems, don't panic yet and start throwing all kinds of treatments at the tree. You *can* kill a plant with kindness (I speak from experience). Start by getting a positive ID of a disease. We will be glad to help but your county's Extension Program is also a good resource, especially if you can physically bring them soil, leaf or branch samples to show them to help them with their diagnosis.
sunpath8
Location: Western Washington
Posted: May-12-2005 at 10:35am
Wow. Thanks for all of the information Lisa. I think I'm going to start by looking at things more closely and being more patient. The new leaves haven't opened up yet and if everything looks good once they do, I'll have some relief.
Thanks again...
Gardening for the Homebrewer: Grow and Process Plants for Making Beer, Wine, Gruit, Cider, Perry, and More
By co-authors Debbie Teashon (Rainy Side Gardeners) and Wendy Tweton