Thank you that makes sense. I live in Miami, Florida and I keep mostly succulents on my 10th floor apartment balcony due to the intense heat, so it so it would just get more light than normal. But I think this kind of plant can handle bright light and heat?

Oh wait, just realized I might spreading the mites to the other plants. Should I keep spraying the insecticidal soap on the pot soil and plant stubs or is that too harsh?

I'm not it qualified to advise on conditions in Florida but personally I'd just chop it right back and stick it outside. But do it over a few days to acclimatise it to outdoor conditions. I've never use insecticidal soap, or any insecticide, so can't comment on that. If you get a good rain I'd stick it out in that too. Bugs love indoor life: no predators, no wind, no rain.

I agree with floral's advice. And fwiw, if mites are the issue, insecticidal soap has minimal effect. Mites are not insects and need a specific miticide to control, if not hosing them off routinely with water.

Neem oil can be a good choice for this. And it controls insects as well as mites and also has some mild fungicidal properties as well.

When was the last time you divided this plant, or simply root pruned it? Asparagus ferns develop very large root systems with bulblets all throughout; the plants can decline if not maintained properly.

I concur with the good advice to chop it all the way back, but I would take care of that root system, too.

it cannot take direct sun in FL : it's usually planted in ground in shade under trees. heat by itself is not a problem, provided it has enough water.

however, the Asparagus Fern (not a fern at all!) really did well in NYC outside in bright shade under the tree with some very early morning sun. otherwise I had it in the office under fluorescents for sev years growing well and not shedding much to be a nuisance.

I would say it grew too large for your pot and needs to be repotted and kept in the shade : north in FL would be ideal. and well watered of course.

Thank you all for your comments! Sounds like I need to cut it back fully, divide (it has been in this same pot for several years) and then treat with neem as it grows back. I will keep it inside as my balcony sun is very strong and as i mentioned, in the past only succulents have thrived there.

I just wanted to thank you all for your comments. I cut it back as recommended and that saved it. I moved to a new apartment with a shaded garden patio, it is now outdoors, happy and mite free.