Interiorinspirations, you are right, your plant is Magnolia figo aka Banana Shrub or Port Wine Shrub. It is not Magnolia soulangeana (sp) which is a deciduous Spring bloomer and bears little resemblance to your tree.

my guess is Salt Cedar , Tamarix ramosissima or relative. It is a beauty BUT it is a invasive in desert riparian areas. You might want to check Arizona's invasive list.

I would guess magnisium deficiency from the "arrow head" shape in the center of the leaf. Being a macronutrient, lack of magnesium effect older leaves first. Its very common in Florida soils.

I have a lot of this pattern. It was offered as a premium at Meijer grocery stores in the mid-west in the mid 1980s. I had "earned" a few pieces and then received ones an older relative had after she died. I continued to get more after her death so I'm certain of the time period mine were acquired. I have one serving bowl stored in the original box. It is labeled Sweet Serenade and indicates it is dishwasher safe. However, the colors faded a lot on ones I washed repeatedly in the dishwasher. I kept some unfaded ones that I use only occasionally to remember Grandma. She loved purple and told me she was paying for them and not waiting until she had earned enough premium points to get them for free.