I just brought home a Dracaena fragrans a couple of weeks ago, and it is in dire straits. Hoping someone here will have some ideas.
The problem(s):
Leaves turning brown from the base of the leaf (not the tip). Brown leaves easily pull off with just a tug. This seems to be happening to leaves near the top of the stalk.
White fuzzy substance just visible at the tip of the stalk, near the small new leaves.
Yellowing leaves.
Small holes in some leaves.
I have considered lots of theories but am not sure what to think. Some things I've considered/tried:
Too much sunlight? I originally placed the plant right next to a southwest-facing window. We are pretty far north (New Brunswick, Canada), and during the winter I figured a jungle plant would prefer all the sunlight it could get. I've subsequently read that the dracaena fragrans developed in shaded conditions; maybe it was too much light? I have moved it away from the window.
Too cold? There is a heater right under that window, so I thought the plant would stay nice and warm. But my husband says the top leaves look almost like frost damage to him. Maybe the chill from the window damaged the top leaves?
Over/underwatering? I've read all the warnings about overwatering, and made sure to test before watering by feeling the dirt with my finger at least 1-2" below the top. It often felt wetter than I expected, and as a result I've watered less than I would have otherwise (about 1 liter every 2 weeks). Maybe this is still too much? The pot does have a drainage hole.
Fluoride in the water? We have well water and I don't know what the fluoride concentration might be. I have ordered a test kit; in the mean time, will leave water out for at least 24 hours to let fluoride/chlorine evaporate before watering, though I've read conflicting reports as to whether this actually works.
Too dry air? We have a Venmar air exchanger that controls the humidity in the house, and in the winter it does get pretty dry. Maybe a tropical plant needs more humidity? Though I've read that humid conditions can also contribute to fungal infections, which leads to my next point...
Fungus or pests? There is a white, fuzzy substance of some kind visible in the crook of the top of the stalk, by the newest leaves. Google has suggested mealybugs, spider mites, and powdery mildew. I haven't been able to find any bugs anywhere on the plant, but the fuzzy substance doesn't look quite like the photos I've seen online of powdery mildew, which seems to be spread in a thin, even layer over the entire surface of leaves. This is concentrated in one spot and is maybe 1/2" deep.
So, maybe multiple problems going on at the same time. I'm frankly just kind of amazed and dismayed that this nice-looking plant has gone downhill so fast. I have other houseplants that seem happy enough in the same room (a fuschia and an ivy plant). Any ideas?