I'll remain calm and focused on the facts, Brent, and I'll refrain from any name-calling. First, I never said it WAS a Mg deficiency, only that if it is a nutrient deficiency, it's likely to be Mg. I think you offered a theory based on a subjective interpretation of what you think a Mg deficiency should look like based on a net search or a book, and on a plant you have never seen. If I am wrong, I apologize, but my being wrong on this point puts you in possession of enough science to argue this point from a scientific perspective, so can we keep it that way, please? I based my reasoning, in part, on the fact that I sent Mike the fertilizer he is using (MG). The fertilizer itself contains NPK, Fe, Mn, and Z. I also added STEM micronutrients to the fertilizer to insure that all nutrients (except the two that are not commonly soluble) would be furnished. The only elements missing from both the fertilizer AND the STEM are Ca and Mg. Though I stated I'm not certain it IS a nutrient deficiency, it's difficult to argue against the logic that IF it is a deficiency, it is almost certainly one of the elements not being supplied (especially since bark and peat based soils are known to be low in both Ca and Mg) or one that is pH induced. We can eliminate the pH induced deficiency of Fe because Mike is growing in a peat/bark blend that he did not lime, which means the pH of the soil is probably quite low, and there is very little or (practically speaking) no Ca or Mg in it. The only other thing that would block uptake of Fe is a toxicity of Mn, and with his fertilizer program, that's not happening. I'll point out again that while experienced plantsmen don't necessarily ignore the photographs offered as being illustrative of deficiency symptoms, they do know that symptoms vary widely, and put far more stock in the known chemical aspects of nutrition that do not vary than in photos or written guidelines that are subjective and guaranteed to vary by plant. I already stated this above, so I'm not falling back on anything, I just didn't feel like retyping it. ;o) Take care. Al

Maybe "cheating", but Grafted (onto G. thunbergia) gardenias by Monrovia (sold in many nurseries or directly thru website}, though $$ are much hardier/less fussy with watering & dying!!! The only plant I have truly killed is a gardenia! (Rose & fragrant flower nut.) I have an August Beauty (nursery person thinks since tag fell off), whose flowers are Huge! (3 1/2" in Fremont, CA in a 21" pot, now 4 years old & entire plant is enormous 4' x4'x3' with a slight weeping habit.). P. S. It did well but has really started to take off in the last 2 years once I was brave enough to cut off a strong shoot that never really had the right leaves & no flowers, finally figured out that was a "sucker" from the rootstock though situated smack in the center. That said, I've just started growing a double flowered Arabian Jasmine Sambac "Summer Soul" also Monrovia (pic). The flowers are huge for a jasmine 1-1 1/2" & the scent is heavenly (TDF), this beats everything else I have ever grown for scent hands down no contest, roses, gardenias, other jasmine etc.!!!!! P. P. S. Tried several other fragrant "gardenia-like" plants. Easier to grow but not impressed with strength/quality of scent on any. Including: African Gardenia (Mitriostigma axillare) & Orange Jasmine (Murraya paniculata) from Logee. Vietnamese Gardenia (Gardenia (Kailarsenia) vietnamensis) from Top Tropicals, & Double-Flowering Crape Jasmine (tabernaemontana divaricata 'flore pleno') from Kartuz greenhouses, also super slow 1st year. All outdoor pots in Fremont, CA, acid-loving potting soil, & no fertilizer till 2nd year just to be safe.

If a leaf here or there turns yellow and falls off, that's normal. If lots of leaves turn yellow and fall off, the plant is dying. This is common to gardenias because they are very sensitive to errors in watering-- too much or too little, or quite often, too little followed by too much. If the leaves seem to be losing the vibrant greenness, then it might be an iron deficiency. As you can see, diagnosis is not always easy, tho IMO, a dying plant does start to just look terrible, and you can't miss it. A dose of epsom salts (magnesium sulfate) should produce a greenup if it's a mineral deficiency. Especially the new leaves, if any, will come in a dark vibrant green. Good luck.

It's just a guess on my part, but maybe your plant could use some epsom salts? That usually causes yellowing of older leaves anyway. My one plant had its leaves turn black but not sure why.