Can this Monstera be saved?

Question: This Mexican breadfruit plant is >30 years old.  It was happy and healthy until recently.  It's been in my daughter's care for the last year while I was out of state.  It either doesn't like her apartment or her care of it.  Until last night, it was sitting in front of the sliding glass door you see in one picture (along with an equally sick pothos).  The window facing SW but the balcony from the apartment above reduces the amount of light that comes in.  My daughter said it was doing fine until about two months ago.  I noted that the main a/c vent for the apartment is about 12' to the right of the sliding door and there's another vent almost directly overhead.  I moved it farther away from the window (it has always liked bright indirect light) and away from the a/c vent.  I have not tried to un-pot it and check for root rot or bring rootbound as my daughter said a friend recently added more potting soil and fertilizer and I didn't know how many more shocks it could take in a short time.  It's in standard HH plant potting soil.

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied July 01, 2024, 4:55 PM EDT
response: While we're unable to concretely diagnose the issue from the photos since we can't see much clear detail, our prime suspect given the degree of decline is root-related, either over- or under-watered (at least at some point, even if not consistently). Does the container drain well, with at least one drain hole in its base? If it sits on a saucer, is the drained water emptied promptly after watering? (If left to air-dry instead, for example, that extra water may seep back into the potting mix and over-saturate roots, depriving them of oxygen and causing them to die back.) Is the plant only watered once the top inch or two of potting mix is allowed to get fairly dry between waterings?  A plant ailing this much should be repotted promptly if root decline is suspected (especially due to over-watering), because it won't get any better otherwise. Worst-case, if you find that too much root loss occurred (we suspect it has, otherwise the leaves would not be wilting so much), then you could try propagating the plant and discarding the old roots. Take cuttings of the top growth on stems that are healthy (that is, not shriveled and semi-brown), and each node could potentially root, given enough time. Monstera tend to root easily if given high humidity and a damp substrate, like a bed of lightly-moist sphagnum moss or moistened potting mix which can be placed in an enclosure or tent of sorts to retain humidity, at least until roots form, when it can then be weaned-off to more ambient room humidity.  Potting mix is best replaced for plants in the same pot for more than a couple years, but not by adding more to the top of a container; rather, the plant should be unpotted, old mix shaken off the roots as much as is possible, and new mix used in its place, whether the plant is going back into the same pot or into a larger one (or a smaller one, if roots were lost in the meantime). For the future, fertilizer should not be used on a plant that isn't healthy, as the roots won't be able to make use of the nutrients; over-fertilizing can also damage roots and interfere with moisture absorption, especially if the potting mix is several years old.  If it would help to have the plant examined in person (for root rot), you could try bringing it to a local Master Gardener plant clinic in your area. Roots killed by over-watering tend to have a mushy texture, pull apart fairly easily when tugged, and will separate into an outer layer with a stringy inner core in that case. They also tend to be brown, versus a more creamy color for live roots, but root color isn't always a reliable trait by itself. Roots dead from other causes (or which are still alive) take more force to break, and tend to snap cleanly in two when pulled apart.  Miri

responder: The Question Asker Replied July 11, 2024, 2:45 PM EDT
response: Could this have been caused by pesticide overspray?  Both this monstera and a pothos plant suddenly went into rapid decline after being luxurious and healthy for 30 years.  I'm wondering if the apartment's exterminator got sloppy with their bug spray and hit the plants instead of the baseboards.  Stephanie

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied July 11, 2024, 2:50 PM EDT
response: Hello Stephanie,  The symptoms the plant is exhibiting do not align with typical phytotoxicity symptoms. (Phytotoxicity is plant tissue damage from chemical exposure.) If root rot (or root loss from any cause, including under-watering) is a contributing factor, then plant decline can be rapid, regardless of its age and establishment.  Miri