So I see today there is a large dark area with no bark. Magnolias are prone to honey fungus (Armillaria) attacks where the bark may eventually fall off over a section where the fungal fans have been spreading out over the wood beneath and decomposing it - perhaps that is what is happening in this instance. Honey fungus is a wood eater than doesn't always wait for trees and shrubs to be already dead beforehand.

I stop fertilizing when temps rise above 80-85*. High temps make roots and the above ground parts of plants very lethargic when they need water most. How readily water moves into cells depends on the level of solutes within the cell. The higher the level of solutes in the cell, the easier it is for water to pass through the semi-permeable cell membrane and into the cell. Conversely, the lower the level of solutes in the soil solution (free water in soil), the easier the cell solution passes the membrane into the cell. For a high % of terrestrial plants other than cacti, root function begins to drop off at root/soil temps of about 80*. If the pot is shaded, root/soil temps usually lag ambient air temps by 10-15*F due to evaporative cooling, so as long as the soil is moist, air temps in shade would need to be in the mid 90s before there was a serious issue with root function. In full sun pounding the pots, soil temps can be much higher - at least 15* higher than ambient air temps in most cases, though that varies too with soil moisture levels and air movement. High root temps are a stealthy attacker. Most often, you won't even realize the damage done to roots (especially trees) on the sunny side of the pot until late fall or even early spring when branches on what was the sunny side of the tree start dying and root rot becomes an issue to deal with. So to be safe, I stop fertilizing at 80*F which facilitates water uptake and movement in the plant. That is also why I try to use controlled release fertilizers sparingly. Their release rate is driven primarily by temperature, so when temperatures reach the point where you want to pull back on the level of salts in the soil solution, controlled release fertilizers will have rendered the grower with no control other than trying to scrape the fertilizer prills off of the top of the soil. I like and feel as though I need the control over nutrition offered by synthetics like Foliage-Pro 9-3-6 in order to achieve the best results. I do use Osmocote-Plus sparingly for younger plants which need to develop more mass before they are started along the path to becoming a bonsai, but not on the trees which are in the stage where I have started developing finer branching and am reducing leaf size. That and beyond is when control is most important. For other hobby growers not saddled with the concerns that come with bonsai, it's simply trying to make it easier for the plant to get water when it needs it most. Al

its september.. days are getting shorter.. and trees are shutting down.. the result of shutting down.. is ugly leaves.. we do not treat leaves that will fall off in a few weeks or a month ... trees that are stressed.. can shut down early... stress might be heat.. drought.. hail storm etc.. related.. everything that happened to the tree since the leaves emerged.. causes ugly leaves in fall .. care to tell us what this trees been thru since early spring??? bark maturation and weirdness doesnt really bother me... nothing you can do about it.. other than observe it.... but.. could we see the whole trunk.. including where it goes in the ground.. is the root flare apparent?? ken

I would disagree that you can't fertilize with organic fertilizers in pots, however if you are going to do so you need to be diligent about how you care for your tree, use a medium that is appropriate for and encourages the growth of microorganisms, and avoid plastic pots. You also have to be careful not to use anything that can damage your microorganisms. When you use organic growing methods in containers you absolutely have to treat your soil as, as much of an organism as your tree, and I would not recommend it to someone starting out with citrus. (I grow my own trees indoors in a huge window exclusively under lights and use organic methods. I get fruit every year and my trees grow very well.) Reading your responses it definitely sounds like you have a few problems: water, light, potential overfertilization. You don't "feed" a tree the way you would feed a pet, fertilizer is not "food" in that way, but should instead be applied as necessary to replace nutrients depleted from your soil. Indoors, your trees won't deplete nutrients as quickly due to the low light and slower growth, so you don't need to fertilize as often or at all. As for watering, as mentioned above you should let the tree dry out between deep waterings and watch that your soil doesn't stay wet for too long. (For example: self watering planters are death for many indoor plants). As for lamps, the kind of grow-bulbs or nice looking growing lamps are not going to provide you enough lumens to grow a tree. You could probably use them for little plants that require low light, but a tree needs more than that. A high powered LED lamp is going to be your best bet for a citrus tree. There are options for ones you can install in your house or you could hide them in some way, but if you want your trees to do well you need a lot more light than a standard grow light. I hope this was helpful, and good luck.