well you have a lot of things going on. the top photo looks like a phsiological due to lack of water or too much.
picture number two looks like galls. you may need to use a pesticide.
picture three looks like leaf hoopers sucking the nuts out of the plant. they put there suckers into the plants and leave little speckles all over the leaves.
picture four looks like a skeletinizer eating your leaves.

seems like you have a lot of problems going on at once. hope everything works out.

The first, second, and third image is of the damage from boxwood leaf miners, fairly common in some locations.

The image of the magnolia is blurry. I'm wondering if the plant might not have black sooty mold from or even algal leaf spot. When was the tree planted? Is there any chance of getting an improved picture of at least one leaf? Have you noticed any strange looking bumps along the stem...about the size of a popcorn kernel?

As far as the last image is concerned....have you seen any Japanese Beetles in your location?

There seems to be some difference of opinion on the boxwood and the red leaf bush. If I treat with an insecticide will that deal with both hypotheses?

As for the northern magnolia, a bit more data. While walking around I observed that although the freckles are on all sides of the tree, they are definitely more on the north side of the tree: more leaves have it, and the ones that have it have a greater concentration of it. Which made me wonder if that meant it was more likely fungal. here are some clearer pictures (I hope)

You asked about the stem, so I took a picture of that. No large nobby anything anywhere, but these little things that look like strawberry seeds (though similar markings are on the older hard woody part too)

Finally, while inspecting the tree I found this guy dead in a spider web at about shoulder height. Any idea what he is or if he helps explain either of the issues with the bushes?

There's not a difference of opinion about what is bothering your plants....steven was simply mistaken, lol. The first three images are all of problems associated with boxwood leaf miner. Pesticide treatments will not help at this point. Contact your local extension office for the appropriate timing of control measures in your location.

I am still thinking that the magnolia has black sooty mold, which is a simple mold which grows innocently upon the sugary excrement of sucking insects. With magnolia, the insect is usually a variety of scale. There are MANY different kinds of scale insects that might be on the magnolia...large or small...located along the stems, branches, and both surfaces of the leaves.

The red-leaf plant, which I think is a purple leaf plum...a very commonly planted ornamental shrub or tree....has been attacked by one of their worst pests....Japanese Beetles. I asked you before if you have seen any in your location. Do you even have JBs where you live....which is where? JBs, by the way, are a type of skeletonizer...meaning that they feed on the soft parts of leaf tissue, leaving the veins in tact.

No one here will recommend the use of a pesticide without a bit more information. If your magnolia has scale, it can be found....they don't run, hop, scurry, or fly away. Is there a tree overhanging this plant? If so, perhaps it is the one that has the insect infestation causing the problem.

You may wish to contact your local extension office for some help in the control of your pest issues.

Before spraying any pesticide, fungicide, or any other poison around your garden you need to know what you are spraying for and then what would be the least toxic material to use to control the problem. Sometimes a sharp water spray is all that is needed.
The damage to the Purple Leaf Plumb looks to me more like slugs then Japanese Beetles, and I have had both on the PLP I have.

I live in northern indiana. There is no tree that overhangs the northern magnolia. it is about 10' from my house with nothing above it but sky. I haven't particularly seen japanese beetles, but I havent been looking either.

I called my extension agent today and will send him the pictures and cross my fingers. I'm concerned that you said it may be too late for my boxwoods...does that mean I'll have to tear them out? sheer them down to stumps?

eek!

I didn't mean to indicate that it was too late for your boxwood in general. It might be too late to do much THIS season. Hopefully, considering your location and climate, you may be able to spray to control the pupating maggots (which you can see hanging on the underside of your plant leaves). You need some good LOCAL input. I wouldn't stop putting pressure on your extension office to help you with this. Boxwood leaf miner is probably the most serious of boxwood pests.

Ask them if Japanese Beetles have been visiting yet, while you're at it.

I think that if look carefully and closely at your magnolia, you will find evidence of a scale infestation.

You will find considerable easy-to-comprehend information about all of these problems on the internet...with pictures. I especially urge you to read up on the leaf miner.

Good luck!

Awesome. I sent my extension officer a link to this post, and he says that the boxwood problem is gall, and that I should treat it in the fall with imidacloprid.

He said the magnolia looked like a fungus, but that if the leaf surface was sticky it could be scale, and I should bring in a sample.

Finally, he says the purple leaves look like japanese beetle damage and that I should do nothing but make sure it gets lots of water during dry spells.

Is it possible the boxwoods have BOTH gall and leafminers? If so, would imidacloprid treat both?

I see no sign of gall on the boxwood. I'm writing to you from my Kindle and haven't figured out how to copy links to this thread....but later on I will be happy to show you as many images as you would care to look at of boxwood that look just like yours....in all three pictures. Those 'funny protrusions' are where the leaf miners emerge from the underside of the leaves.

Do me a favor, will you? Remove one of the worst of the leaves from the magnolia and take it to the kitchen. If you can wash that black stuff off with soap and water, we can be certain that it's Black Sooty mold, a simple mold that grows on the sugary waste produced by some insects.

If it doesn't wash off, we'll know that it isn't BSM!

Okay, the leaves on the northern magnolia are not sticky or slick. If I had my eyes closed I wouldnt know anything was there.

Also, the stuff does not wash off with soap and water...any more ideas?