Magnolia - yellow dropping leaves

Asked May 15, 2020, 6:07 PM EDT

Hello, I purchased a home last year with 2 magnolia trees (about 20’ tall, 4 feet wide, drag green glossy leaves and white blossoms). This spring there appear to be many yellow leaves, particularly on the interior of the tree, and it is dropping a lot of yellow leaves continuously. There are some blooms, but many of them are brown at the tips. The green leaves on the tree do look healthy. I Wonder if the branches are too dense, but I have also read to be cautious with pruning magnolias. Do you have advice for how to manage this? What kind of maintenance is necessary for a healthy magnolia? Thank you, Andrea Thoits

Multnomah County Oregon

5 Responses

Thank you for the images.

Even though your magnolia is an evergreen, it will drop leaves all year around. The loss tends to be most intense prior to flowering. Then, too, because the leaves are so large, leaf drop is especially noticeable.

I wonder about the history of the trees while the house was vacant. Far too often, no one waters the landscape during that time. Unfortunately, an extended dry period can stress a magnolia, triggering problems during the following year or more.

So, in an effort to sort out the details, here are some questions for you:
- During which month did you move into the house?
- How long was the property vacant and untended?
- Do you know when the tree was planted? (Perhaps a neighbor may be able to tell you.) If just prior to the sale, it's not yet established and will need regular attention to its water needs for the next 3 years or so. (We can discuss that later, after I receive your responses to the above questions.)

Then, too, how often have you watered the tree since you moved in? Please describe the method such as hand-held hose, sprinkler, soaker, or drip.

Another potential complicating factor is that the tree is tucked into a rather small space. It may not be receiving adequate water even during our wet months.

As for the flower buds, their condition is pretty typical for our recent weeks of intermittent, but frequent, showers and rainfall.


Hi Jean,
Thank you so much for your reply, I can already tell I will learn a lot from this exchange! To answer your questions: We moved into the house in May of 2019. The house was partially occupied during the prior 9 months, but I doubt they were irrigating during that time. The tree was planted around 2013 per neighbor report and landscape records. Upon investigation it does appear that the soil beneath the tree directly surrounding the trunk is dry (which surprises me because the soil outside the perimeter of the leaves is very wet!). There is an automatic sprinkler system which provides irrigation to the area during the dry months (haven't activated it yet this year), but again as I look closer it appears that water to the tree might be blocked by the hosta plants. It seems to be coming into focus that I am not getting the tree enough water! Please let me know your recommendations for a tree of this size (I would estimate about 20 feet). Thank you! Andrea




Andrea,

Thank you for the followup.

Yes, it makes sense that the soil beyond the branch tips will be wet from recent rains even while the soil beneath the canopy (closer to the trunk) is dry. It's dry because the large leaves are quite dense on a magnolia and, thus shed rainfall at the dripline and beyond.

It's likely that the sprinkler system is providing too little water for the tree. The reason is that trees should receive enough water to thoroughly moisten the sol to 8 to 10 inches deep throughout the root system. Then, too, the cobblestones/paving isn't deliberately watered.

After the irrigation system is activated, check the soil with a trowel to determine just where it is moist, wet, or dry.

It may be helpful during our dry months to setup a soaker hose in the planter area at the left. Then, every 2 to 3 weeks (as needed) hook up a hose and mechanical timer to run the system for an extended time, perhaps an hour or two each time.

Because a soaker hose should only drip or ooze (not spray) it requires an extended time to provide the necessary water for a tree. You'll need to use the Trowel Test to determine how long that will take for your soil.

Thank you so much, I will proceed with this plan.


Moving forward, do I need to plan for pruning of the tree in the future? What is recommended for magnolias?

Thanks again!

Magnolias are rather symmetrical trees and, thus, seldom need to be pruned.

Because the tree appears to be quite close to the house, it may need attention in the future. If that occurs, I suggest you contact several Certified Arborists who have experience with magnolias for on-site evaluations. (Such persons must pass a test, then acquire continuing education.)
You can locate a Certified Arborist by searching with your zip code at https://www.treesaregood.org/. Most local companies service clients in all 3 metro counties.