What is wrong with these magnolia trees?

[risingphoenix]

Hello. I have several little gem magnolias that were planted this spring. Recently, they've begun to struggle, and I can't seem to do whatever they're needing to recover.

Their leaves begin to discolor and ultimately turn brown and fall off -- for some trees, this has happened more aggressively than others. My native soil is clay, which is always a challenge, but the soil was amended during planting. I'm watering them of course, but could they still be requiring more? With the drought this summer, I don't think over watering is the issue. Or could this be a fungal problem? I'm always concerned about verticilum wilt.

If anyone has any idea what's happening to them and what I can do to save them, I would really appreciate it.

 

[DirtMechanic]

Well for one thing, they generically come from the southern hemisphere and their seasons always seem reversed. They like to lose leaves in the summer and grow in the winter it seems. The upward cupping leaf is a stress signal though it may not be for that plant. They require little sustenance, so let me ask about that seemingly benign word, "amended"? What, exactly, did you put in the soil? Have you fertilized lately? With what? are you using acidifiers? And would you agree that the leaves either seem to be either nicely darker green or dead? No real in between stages generally? They grow slowly so even though they were planted 6 months ago they may only be shocking as root development begins and the associated leaves reflect what is going on underground. When you put you finger in that soil is it dry or wet right now?

 

[big rockpile]

Got one that died but have a pretty good idea what happened. I ran over it.

Got another one doing fine I'm worried about our drought.

big rockpile

 

[risingphoenix]

Well for one thing, they generically come from the southern hemisphere and their seasons always seem reversed. They like to lose leaves in the summer and grow in the winter it seems. The upward cupping leaf is a stress signal though it may not be for that plant. They require little sustenance, so let me ask about that seemingly benign word, "amended"? What, exactly, did you put in the soil? Have you fertilized lately? With what? are you using acidifiers? And would you agree that the leaves either seem to be either nicely darker green or dead? No real in between stages generally? They grow slowly so even though they were planted 6 months ago they may only be shocking as root development begins and the associated leaves reflect what is going on underground. When you put you finger in that soil is it dry or wet right now?

Thank you for your reply. That is very interesting to know, I didn't know they originally came from the southern hemisphere. By amended, I just meant that the nursery I bought them from recommended incorporating a potting mix with the native soil while planting. I usually like to use my homemade compost, but they had a specific mix they suggested, so I thought I should use it just in case. I used nothing else on them, no acidifiers, etc., until they started showing problems. Then, I just gave them some fish fertilizer to give them a nitrogen boost and some worm castings.

The leaves seem to turn dark yellow/orange, slightly spotted, wilt, and then turn brown. I wondered about transplant shock, but I have lost one tree completely, so that is why I am concerned about the rest.

The soil is moist right now, but that was definitely a struggle to maintain in the extreme temperatures this summer. I watered as frequently as I was physically able, sometimes daily, but the soil would still dry out at times (even with slow/deep watering), and of course clay is like concrete when dry. I'd read that only an inch or two of water was needed per week for magnolias, but that would leave my soil a crusty canyon. I've kept mulch on them since they were planted. The weather has since cooled and I've been able to keep them consistently moist (not wet), so I was hoping they'd show some improvement, if the extreme weather was an issue for them this summer. But they just continue to look worse.

Unfortunately, while I've gardened for many years, I have little experience with trees. The red maple I planted at the same time as the magnolias is thriving, luckily, but alas, they are more adaptable to clay than magnolias, from what I understand.

 

[risingphoenix]

Got one that died but have a pretty good idea what happened. I ran over it.

Got another one doing fine I'm worried about our drought.

big rockpile

Will try to avoid running over any of them, thanks for the heads up.

The drought was brutal this year. Looking like we might get some rain this week, hope you get some relief soon, too.

 

[DirtMechanic]

Thank you for your reply. That is very interesting to know, I didn't know they originally came from the southern hemisphere. By amended, I just meant that the nursery I bought them from recommended incorporating a potting mix with the native soil while planting. I usually like to use my homemade compost, but they had a specific mix they suggested, so I thought I should use it just in case. I used nothing else on them, no acidifiers, etc., until they started showing problems. Then, I just gave them some fish fertilizer to give them a nitrogen boost and some worm castings.

The leaves seem to turn dark yellow/orange, slightly spotted, wilt, and then turn brown. I wondered about transplant shock, but I have lost one tree completely, so that is why I am concerned about the rest.

The soil is moist right now, but that was definitely a struggle to maintain in the extreme temperatures this summer. I watered as frequently as I was physically able, sometimes daily, but the soil would still dry out at times (even with slow/deep watering), and of course clay is like concrete when dry. I'd read that only an inch or two of water was needed per week for magnolias, but that would leave my soil a crusty canyon. I've kept mulch on them since they were planted. The weather has since cooled and I've been able to keep them consistently moist (not wet), so I was hoping they'd show some improvement, if the extreme weather was an issue for them this summer. But they just continue to look worse.

Unfortunately, while I've gardened for many years, I have little experience with trees. The red maple I planted at the same time as the magnolias is thriving, luckily, but alas, they are more adaptable to clay than magnolias, from what I understand.

I would treat them as one might a blueberry bush. Here our clay has a natural 5pH. Its actually odd because most are alkaline. This is due to the large amount of rain washing away the liming agents.

That maple is telling in 2 ways. One, they tend to have roots above the clay so they can breathe, and two they do not necessarily like super low pH. Slightly acidic is what google says. I think the main thing is the drainage though. We have huge maples on hills or berms and none in the low spots.

You may care to dig those holes deeper and use something coarse down in the bottom. The more I look at it the more it reminds me of some camillia I lost for the same reason. I can plant above the clay or in really deep holes where water can pool low safely, but that in between, as deep as the pot etc type hole, always seems to cause me problems.

I mean these are not native plants and all that so sure they need that extra care until they figure it out. They have some of that suffocation behavior, losing leaves first, then branches as that root gives up, getting smaller to match the lack of air. Check that pH, above 6.5 is bad. Pine bark mulch is a pretty good amendment here as it really helps the drainage and there is a chemical that resists breaking down into compost too fast.

 

[risingphoenix]

I would treat them as one might a blueberry bush. Here our clay has a natural 5pH. Its actually odd because most are alkaline. This is due to the large amount of rain washing away the liming agents.

That maple is telling in 2 ways. One, they tend to have roots above the clay so they can breathe, and two they do not necessarily like super low pH. Slightly acidic is what google says. I think the main thing is the drainage though. We have huge maples on hills or berms and none in the low spots.

You may care to dig those holes deeper and use something coarse down in the bottom. The more I look at it the more it reminds me of some camillia I lost for the same reason. I can plant above the clay or in really deep holes where water can pool low safely, but that in between, as deep as the pot etc type hole, always seems to cause me problems.

I mean these are not native plants and all that so sure they need that extra care until they figure it out. They have some of that suffocation behavior, losing leaves first, then branches as that root gives up, getting smaller to match the lack of air. Check that pH, above 6.5 is bad. Pine bark mulch is a pretty good amendment here as it really helps the drainage and there is a chemical that resists breaking down into compost too fast.

This was extremely helpful. I think you've nailed what's happening. I tested the pH, and you were right -- it's sitting at alkaline, definitely above 6.5. So I'll be working on that pH for sure. Equating them to a blueberry bush really put this into perspective for me. And that tip on putting something coarse in the bottom of the holes is brilliant.

What do you use to test your pH, if you don't mind my asking? I'm always changing my mind on what works best.

Thanks a lot for your time again. I really appreciate it.

 

[DirtMechanic]

This was extremely helpful. I think you've nailed what's happening. I tested the pH, and you were right -- it's sitting at alkaline, definitely above 6.5. So I'll be working on that pH for sure. Equating them to a blueberry bush really put this into perspective for me. And that tip on putting something coarse in the bottom of the holes is brilliant.

What do you use to test your pH, if you don't mind my asking? I'm always changing my mind on what works best.

Thanks a lot for your time again. I really appreciate it.

Glad to help solve a garden puzzle. I always learn and that helps me right back. And I do not even particularly like magnolia. When the leaves drop you will see why!

As to pH, I have tried different methods and settled on a soil stick. They cannot be trusted during a soaking rain (too much water) or a dry spell (to little for electric values) but the day after a rain - when the soil is in that pristine moment of drained moistness - they read close enough for me. I mainly use it for a direction indicator. After all you cannot just dump acidic or alkaline materials en masse because of the toxic front that can be created. So it helps me dabble along up or down. This is better for the plants and my wallet. Just remember some acid like vinegar to keep the tip stripped of oxidation and electically efficient. Plunging it into the soil 20 times across my yard acts like a sandpaper as well. Clean it after use.

 

[risingphoenix]

That is one of the great things about gardening, there is always more to learn. We have an old magnolia on our property we enjoy every spring, so I'm hopeful that some extra attention will help get these new ones through. I'm glad to know what I'm fighting now, that's half the battle!

Thanks a lot for the tips on the soil stick too. It's really great to have a convenient way to check on pH.