I am definitely doing something wrong with this plant (the one on the left). I really don't know what is wrong with it (I believe it needs to be re-potted - I'm not doing that). There are seven other's in pots, just like it, and they are doing just fine (look very healthy).
I'm not the best gardener. I went outside yesterday and trimmed all my shrubs (a lot of shrubs!) - it took hours. I cleaned up my flower beds. I picked up trash in my yard (the kids leave - cuz this is a public park, you know.) I watered. And ... I pruned a few of my crepe myrtles. I'm pretty sure it is not the time of year to prune crepe myrtles, but I don't care about that "time of year" stuff. If the plant is in my yard and it's looking shabby and needs to be cut back - I just hack away (I wish someone would do this to me - just come up and trim my hair when I really need a cut).
I like working in my yard. I like a pretty yard. But ... I am not going to go to all the trouble of feeding, re-potting, thinning out, preparing the soil ... ever! I will trim, mow, add mulch, water and pick up trash - but that is a far as I will go. If a plant wants to live in my yard, it needs to be happy with a good cut, every now and then, and water. And ... I can only clip anything into a "ball" shape - no animal, cartoon characters, squares or topiary's, here. An occasional cut and water - that's it.
This plant is going to die - I don't care. I'll buy another one (brand new and healthy) to replace it. The cost of a new plant, is worth it to me, not to have to really learn all about gardening. I don't have room in my brain to store all that: too much light, not enough ash, too much water, this kind of fertilizer is for this and that is for that - crap. Water - that's all I really understand and that is definitely all I want to know.
On the upside ... most of the plants in my yard have conformed and are going along with my rules. The one's that didn't, are ... outa' here.