Hi Cat,
My observation with Dracaenas, they do not respond well to fertilizers. Better to keep off the fertilizers especially in winter, tropicals are in slow down growing due to winter. Application of fertilizer to a very stressed plant will not work either. Got to give the plant some time to recover or get back to its usual growing speed during Spring. Too much fertilizer application will just result in root and leaf burn.
I am not sure if the plant in the plastic container is still alive looking at your photo. How does the stalk feel/look like inside? Is it green or too soft and mushy? Typically if it is a firm trunk, there may be a fighting chance, but a stalk with no green leaves to it, and depending on the condition of the roots it may just be dead roots. Does it seem the roots are growing?
Are these plants growing near a window at least? They are low light plants, but they still need some bright light and warmth.
