I mainly use ammonium sulfate for this and my blueberries. I've noticed acid loving plants really seem to like it. If you're looking for pure ammonium sulfate (not the pellet stuff they sell at home depot) you can buy it on ebay in huge boxes for pretty cheap and that'll last you forever. I mix about a tablespoon with about a half gallon of water, then use that as a concentrated mix and add a little of it to water every now and then during the growing seasons. It's pretty safe for the plants to use it like that.

Do you keep yours outside over winter? I brought mine in early last winter (we had an unusually cold November last year) and I'm trying to figure out if there's a place I can keep it in the yard where it won't die from the cold.

Good to know, thank you so much. Which size of the ammonium sulfate did you purchase? here is a few from eBay search

http://www.ebay.com/sch/i.html_from=R40&_trksid=p2050601.m570.l1313.TR3.TRC2.A0.H0.TRS0&_nkw=ammonium+sulfate&_sacat=0

I have been using KeRex Super Iron Chelate for pale leave problem, but it does not work. I will definitely try ammonium sulfate.

Michelia Alba is not easy to grow, extreme heat and cold will harm them. I never put mine out open in the yard over the winter, especially cold one like last year. When they were small I brought them indoor. Last year due to their sizes, I moved all of them onto back patio that has two walls and two open sides with hooks along the eaves . We hooked and wrapped the patio with blue sheets from Home Depot and old blankets. (Hope this makes sense). Putting them on in the evening and removing them in the morning surely was a chore. Luckily we did not have many real cold days, so the work was tolerable.

Do you grow Grand Duke? It is my 2nd favorite plant. Actually it is fairly easy to grown in Phoenix area.

I bought the big 25 pound box a few years ago. At the rate I'm currently using it, it'll last a really long time. This year I've been using it for most of my potted plants as it seems to do well with all of the ones I've tried so far.

That's a good idea with the sheets over the patio. My Michelia Alba grew a lot this year and would take up a lot of room in my plant area indoors, so I might try something similar to that. (maybe a covered pvc structure in my patio?) Did they keep their leaves with the blanket protection?

I haven't grown the Grand Duke yet but I looked it up and it looks nice. I do have an Arabian Jasmine, but its flowers are the smaller ones that grow in groups. Do you keep your Grand Duke in a container?

Thank you again for the Ammonium Sulfate info.

No, there is no harm to Michelia Alba's leaves, they all survived. During last coldest winter nights I put sheets on top of the plants in addition to keeping them on the covered back patio. I am not sure if this extra protection helped, or is necessary.

I also have Arabian Jasmine, it is no match for Grand Duke. I did not check where to get Grand Duke in Phoenix now as mine was from Bakers. Unfortunately, Baker was out of business. I planted mine next to the front patio, they are semi protected from Phoenix roasting summer sun. I have one planted in a pot. If you are interested, send me an email through my profile.

Fun pics and information--thanks for the nice, informative discussion on this plant. It sounds like a real drama queen, hah, but it's good to hear how you're keeping yours so healthy. Anything that smells pretty is a winner in my book. Enjoy!