the missing part of the leaves doesnt intrigue you ??? do you recall any hail storm last year??? are these new emerging leaves ... or wintered over leaves??? .. if last years leaves ... what if anything interesting happened over winter... was the tree just planted last year.. or an older tree??? any chance at a pic of the whole tree ... and where are you.. big city name .... welcome to the forums .... ken

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.

The only information you have given us is 'they are the exact same tree' and that may be true but subtle differences in location can change variables in these cases. A boulevard tree, for instance may get some salt from snow plowing. A tree close to other trees will not get as much sun as others in the open. That's why you might see some trees already past peak with fall colors while others that are the exact same species still have green leaves. This year in my country, color change has been scattered with spotty frost pockets and strong winds. Some years everything seems to change at the same time, some years not so much.

Watering from the bottom ensures all the dissolved solids in tapwater and fertilizer solutions remain in the grow medium. It can also upset the balance (ratio) of nutrients, one to the others, such that an excess of 1 nutrient makes it hard for the plant to take up enough of another nutrient (called an antagonistic deficiency). A level of dissolved solids (salts) in the soil that is too high, makes it difficult for the plant to move water to all of its parts with normal efficiency. Too, it's best to water slowly from the top, using enough water to fully saturate the soil and allow at least 20% of the total volume of water applied to exit the drain hole, which helps to flush any accumulating salts from the grow medium. The plant is definitely in want of more light. If you have a brighter spot you can acclimate it to over the course of a week to 10 days, it would provide a significantly greater opportunity for your plant to realize a larger measure of its potential, bestowed by Mother Nature. How do you determine when it's time to water the plant? Have you been fertilizing regularly? Nutrients are the building blocks plants use to grow and keep their systems orderly, so it's important when growing in containers that the grower shoulders responsibility for ensuring appropriate nutritional supplementation. Foliage-Pro 9-3-6 is an excellent product for houseplants, and it provides all nutrients required for normal growth, so it's all you need in the way of nutrients. Questions? Al