Looks like spider mites; you won't see them without a good magnifying glass. A good wash outside or in the shower will go a long way to getting rid of them. My advice... lose the fertilizer spikes and replace with a good soluble citrus fertilizer applied 3-4 times per year according to the label. Your tree looks to be a little underfed; and unhealthy trees are more susceptible to spider mites. I would also get a good foliar fert. and give your tree an application of that about every 15 days; I like Bayer Bayfolan Forte; lots of container growers here use Foliage Pro... there are others. Your tree looks a bit leggy; I am guessing it gets less light than it would like.

I am new to gardening, but have a background in turf. I planted 3 twist and shout hydrangeas this spring and they are doing somewhat well, I just noticed that some on the leaves are fading to purple from the middle of the leaf to the end. It's not everywhere, just some here and there. I also noticed that this is happing on stems that are beginning to produce flowers. Also inside the plant some leaves are turning yellow-white (the vein also) and will fall off to the touch. This is happening to my Tardiva's and my limelight as well. Is this normal. I have noticed that jap beetles or some incsect have been chewing on the leaves last week, but I sprayed imidacloprid and cyfluthrin twice, 7 days apart. They get late morning sun to filterd evening sun. Any help would be greatly appreciated! Thanks in advance.

Jennifer —-(Spraying with Neem Oil and or and other mixtures to eradicate the insects organically could still harm those beneficial insects. Some people will just let those pest stay on the tree because they dont want to harm them. Its a difficlt choice to make for some and you need to understand that some bad infestations that might get out of hand and could cause your trees to become weak and allow other diseses to slowly kill your tree. i always try and let Mother Nature work on the right balance of the pest verses the beneficial insets to keep everything in check. But sometimes i will have to step in and use more than organic to combact the problem. its up to you to decide what is best for your tree. Laura Even those that eat leaves ___ Katydids 🌺

Dave. Hi.. This link should be of great help for in ground growing) http://homeguides.sfgate.com/care-michelia-alba-104056.html Also Quoted from another member who is good at growing them in ground..Looks like you might have to add a little lime to your soil and use a good 10 10 10 fertilizer...Also I would make sure your ground is very well draining..I would stop using certain chemical since most fertilizers have the nutrients that a plant needs..If you starting adding this or that, too much of a good thing can cancel out another nutrient..For example, too much Mg can cancel out Ca..I would start with your pH and focus of the roots needs..That would mean a fast draining soil and to keep the roots warm if you live in an area like that...Then watch your watering and fertilize with something light.... "Now it is not the season for M. ALBA 's flowering in your zone. And it is not the fertilizing season either. We fertilize our M.ALBA in the end of Feb.or early March when it start to put out new leaves in Southern CA (outside the house). M. ALBA likes warm and humity environment. It likes weak acidc soil (say PH 6.2)and acidic water. It needs heavy fertilizer when it in growing and blooming season. I would suggest you to start fertilizing it when you can move it out of the house and it start to grow new leaves. Any balanced fertilizer will be fine for M. ALBA. I give them Fish Emulsion, 2 table spoon per galon and once a wk.In summer, twice a wk.MiraGrow is good too and it can decrease the ph of our hard water here. Now your M. ALBA stays in your house w/ less light. Just let it sleep which lots of the plants need it in the winter. During this time giving it less water (say once two wks thrououtly). Keep the humity high in the house is a good idea." Hope it's helpful!