This seems a fairly common syndrome of large red oaks but I'm not aware of what is causing it. A couple trees in my neighborhood have been cut down in the past 5 years after similar looking dieback. Any ideas? I'm pretty sure white oaks and cerris oaks are not having the same issue...right?

To answer you original question "Succulents dying, how can I save them?". The quick answer - you won't save them. Throw them away. If you really are interested in growing healthy plants, you have lots of work to do. It's a great hobby, but you can't go into it blindly. I will try and keep this as simple as I can, please don't take offense: - You should not be growing these plants until you have done at least a modicum of research, unless your intention is to only have them as temporary, short-lived decorative plants. These plants were doomed from the start. Poor pot selection, poor soil mix, inadequate light, inadequate air movement, inadequate temperature range, and an owner with a lack of information. I partially blame the retailer for selling an attractive but terribly ineffective mini-garden. - Succulents ARE NOT houseplants. They will not be healthy indoors without significant effort. What you may think are "healthy" plants are instead plants that are tolerant of abuse which can only put up with so much before they start to go downhill. Most succulents need fresh air and sunshine for at least a few months a year. Indoors year-round they are essentially being tortured. -"gnats" are fruit flies. They feed off of organics in the soil, like decomposing peat. Peat is probably the single worst ingredient for growing pot plants. -We have all been in the same position. We have all killed plants in the beginning. What defines success, IMO, is how you take it from there. /rant

Silver or Freeman-hard to tell which, and of course, they are close relatives. The graft failure is an intriguing idea. I've seen such, but in the more well-known case of certain white ash cultivars. In any case, this plant could be cut back to live stems if one is patient. I could do it in just a few minutes. YMMV. The reason this is not so crazy an idea is that this tree will be very fast-growing. Even the little remnant, should you prune as suggested, will quickly shoot up and become a tree again. Why the die-back? Who knows? Sometimes it just happens, and of course, there is a cause, but we don't always know what it is.

I know this is long, Heidi, but I've got personal experience with your situation. To be brief, I'm confident that this tree is not even close to death's door, and would be much better served by fixing the causes of its decline now so it can green up and be much healthier to deal with the stress of repotting next summer. In particular, your ficus was thriving until three months ago, and we know that the decline was caused by low light and poor watering, which means that fixing the root congestion and soil aren't an emergency. To be clear, gardengal is probably right that you could repot now without killing the tree, but because it would be easy to get it green again by correcting the biggest problems now, you would be best off waiting until summer to do major root work and put it in a great growing medium. Then you will be rewarded with a burst of new growth, and you'll soon be pinching growing tips and pruning to control its enthusiastic growth and tell it to fill in all those gaps left by dropped leaves. My experience: I have two smaller roughly five year old ficuses that were completely rootbound and were stuck in a dim corner. I often forgot about watering until leaves started yellowing and dropping, and the I'd fill their tall plastic 'saucers' and left the water there until they stopped soaking it up. In other words, I drowned the roots every time I watered, and maximized the amount of deadly mineral deposits in the soil. Aside from feeble attempts to maintain a few leaves, they had almost stopped growing entirely because their depleted energy reserves made them more vulnerable to attack and only allowed them to put our a few leaves at a time, and most of the buds and leaves that appeared were killed by spider mites. But these are tough plants, so they clung to life for about three years before I finally cared enough to search for answers and found these forums. I immediately started treating the mite infestation, thoroughly flushed the pots (I swear I could hear them sigh with relief), fertilized with a weak solution of Foliage Pro, which has a great ratio of basic nutrients plus all the micronutrients plants need, moved it in front of my best window, which only provides mediocre light, and added bright white (not soft white) 5000k 100W led and cfl bulbs in clamp-on fixtures. Two months later, each branch has about half a dozen new leaves, including some emerging near the stem (a sign that the tree is getting better). It's wonderful to see them getting so green, and I'm already reading up on how to prune them when they get growing again. So Heidi, if I were in your place, I'd start by checking the leaves for spider mites with a bright light and a magnifying glass (they're tiny red dots on the leaves, and you may see little bits of webs on the leaves our branches). Ask about treatment if you find any. Then I'd flush the pot (details below), fertilize with a 3:1:2 ratio fertilizer (miracle gro general purpose granules are easy to find and the right ratio), move it to the best window I had, and put two 100 or brighter led or cfl bulbs in it for 12 hours a day, using a timer. From then on, check soil moisture by pushing a sharpened 3/8" dowel all the way through to the bottom of the pot, and DO NOT WATER until the dowel comes out completely clean and dry (at that point there's still a lot of water inside the soil particles). When that happens, water until about 15% of the water exits the drain holes, let it drain, and then either tilt the pot at 45 degrees for 15-30 minutes after watering to remove excess water, or insert a wick into a drain hole and raise the pot up so the wick won't come in contact with the drained water. You can wait until the surface of the soil is dry to start checking the soil moisture, but after that you should check daily until you have a feel for how long it takes for the poor to dry up. About flushing: flush with lukewarm water, using about ten times the pot's capacity, then give it a weak solution of fertilizer. Use R/O (reverse osmosis) water if possible; water from supermarket water machines are usually $.39 per gallon, and that little pot will maybe need two or three gallons to do the job. My water is hard, so I used R/O water to flush, and because my tap water is hard I use water from my cheap faucet-mounted filter for regular watering. And the reason midsummer is the best time to do something stressful is that 1) ample summer sunlight generates much more energy from the leaves than even a lot of winter sunlight can provide, and 2) the plant is programmed to put energy into new growth in summer, whereas in winter it wants to store it for use in the spring. From several people's experience, including Al (talks), who knows whereof he speaks, if you take two healthy plants and repot one now and one next June, the second will be in better shape next fall than the one you repotted a year earlier. Sorry for my rambling post, and I hope it helps at least a little.