Okay, so I unpotted the ficus:

I think it's root bound.

Bottom view

I'm planning to repot it ASAP, although I'm not sure how it'll deal with the repot.

I'd honestly wait. That really doesn't look so rootbound that it would be the cause of your issues.

There's only one branch with leaves on it though...I know just because a plant loses all its leaves doesn't mean its's dead, but still...when something completely defoliates I get really scared =/

I totally agree and understand. I'm interested to hear what Al thinks.

Basics...

how much light? What direction does the window face? How far is it from the window?

doing through flushes of the soil? Using the dowel method to check for moisture? Fertilizer? If so what and how often?

near a heating vent or draft?

no pests?

Light- SW exposure, same room it was in during summer. It gets a few hours of direct sun in the afternoon. it's about three feet from the window

Watering-yep, I flush at every watering, I use a wooden chopstick. For fertilizing...I've probably done so maybe once or twice during this winter (I'm always petrified about salt buildup in the soil). I use the MG liqua-feed (12-4-8) and use about 1/2 to 3/4 of the recommended dosage.

During autumn the trunk did wrinkle a bit because I was a little forgetful in watering it, but it looks a lot better now.

It is near a heating vent on the ground, but the slots are angled away from the plant. There are vents on the ceiling, but they're rather high up. I've never felt anything from the ceiling while in the room.

And no pests/signs of pests (none that I can see, I did check over carefully). No stickiness, no suspicious dots, no fine webbing etc.

It was bought around two to three years ago, never repotted.

I saved on Ficus microcarpa from a store, they were tossing it away. Once I got home, it took two days for ALL of the leaves to drop. It had been overwatered for a good time.

I did wash away all the old soil and trimmed about half of the roots off.

Then I planted it in fine orchid mulch.

A week later, the branches did die back and dry out when I decided to trim the graft down to the base, all the way to the big root thing.

It took almost a month for it to start growing new branches from the root/trunk, and two days ago I pruned half of them off. Now it has 7-8 branches and is growing vigorously.

What I mean with this is, that they are tolerant trees! But I do have two 100w CFLs what I overwinter my plants with. And mist them a couple of times per day. So some sort of light might make it easier to overwinter these..

And I did the pruning in december, just before christmas. So far it has been also attacked by thrips and couple of good soakings with natural soap has got rid of them, for now. Until their back again..

The last branch is on its way out as of today.

As of now, my plan is to either repot or continue giving it water/fertilizer and hope for the best. What do you all think?

They yellowing of the remaining leaves makes me think it's on its way out whatever you do. Being rootbound wouldn't kill it, it would just affect the nature of the growth.

Equally, is that dust or red spider mite on some of the leaves I can see?

Equally, is that dust or red spider mite on some of the leaves I can see?

Don't think so-it's most likely dust/lint from the air. Every plant in the house has this dust on their leaves. There isn't any fine webbing I can see. I can wipe down the remaining leaves to check for red dots.

GS - It's state of root condition is nothing to be concerned about at this time. The bulbous roots of this plant are a genetic modification that help the plant store water as insurance against the dry spells that come where the plant naturally occurs, so the plant is more tolerant of dry conditions than most plants. Still, if it's lost so many leaves and isn't replacing them with new leaves or attempting to do so, there is something very wrong, culturally speaking, and it's energy reserves are on the verge of being depleted - which means that death is inevitable unless you can turn things around.

I'd stop fertilizing. Flush the soil very thoroughly. Use the up/down movement thing over the sink after you flush to eliminate perched water. Monitor water needs carefully with a tell, and if you are to err, err on keeping it on the dry side instead of too wet. Keep it warm and in very bright light, and be patient. Don't fertilize until you see it starting to push new buds. I think I'd put it on a 4 day schedule that has you spritzing the entire surface area of the plant with a mix of 1 part 70% rubbing alcohol and 2 parts water - just in case it has mites. It does look mitey to me, but I can't trell. If you have a magnifying glass or loupe, use it to check underside of leaves for mites.

Al

Thanks so much Al! Hopefully the plant recovers soon :)

"I think I'd put it on a 4 day schedule that has you spritzing the entire surface area of the plant with a mix of 1 part 70% rubbing alcohol and 2 parts water - just in case it has mites"

So every fourth day I should spray the entire plant with the alcohol mix? Would a little bit on the soil surface hurt?

Also, as of now I think all the branches up top are dying-they're beginning to brown. Will growth be able to sprout from the upper part of the large root structures?

The plant often defoliates during dry spells, then takes off again when normal growing conditions return. Too much water causes a drought response, so if root rot hasn't gone systemic and compromised the plant's entire vasculature, chances are good it will recover ...... thanks in large part to those large food/energy and water storing roots. The plant also freely forms adventitious buds on old wood; so as long as there is viable wood above the soil line, there is reason to expect back-budding.

If you think the situation is desperate to the point you're in fear the plant is going to die before a more appropriate time to repot comes around, I'd repot now. Those bulbous roots that store food and water increase the leeway you might not have with other plants, or even other species of Ficus. Obviously, I'd hope you'd be repotting intro a medium that allows you to water correctly w/o worrying about a recurrence of what you're dealing with now.

A little bit of water/alcohol mist falling on the soil won't hurt, but I would take steps to avoid enough water falling on the soil surface that it soaks in and gets taken up by the roots. IOW, you want whatever falls on the soil surface to evaporate almost immediately and not make its way down into the soil.

Al

So I've watered/flushed it once since Al's previous post. There have been no ne signs of life, but we've got a new problem now-

So two of the three root structures have begun to wrinkle and feel squishy.

When I squeezed the root structure on the right today, some of the bark cracked and revealed the interior flesh. From the bits available, it was green with some patches of red throughout. There was no odor that usually comes with rot.

I plan to repot it tomorrow. Should I cut off the two squishy root structures?

You can try cutting them off, but indications don't bode well for the plant's survival. ;-(

Al

Update:

Got some bad news-all three roots felt slightly squishy when I repotted. Here's some pictures of the plant's base:

Also-there were some were white fluffy spots on the trunk-I'm not sure if it was mold or root mealybugs.

If it does end up dying, I'm going to guess that somehow I overwatered it without realizing it. This caused root rot, which then spread into the main bulbous parts of the plant. Water could no longer reach the leaves, which caused the defoliation.

Couple lessons learned here I suppose-

Be careful about overwatering even if you think you don't overwater, and

Repot each new plant ASAP to make sure no hidden problems are lurking below the soil surface.

Thanks for all your help anyways :)

My rule of thumb is if I feel like my plants need water, I wait another two days :)

I love my little collection of sharpened dowels, even if it takes a few tries to push them to the bottom of the really rootbound pots. They take half a minute to use, require no thinking or guesswork, and never ever lie to me.