I am not positive this is the right place for my topic but I couldnt find a better location. This is my first time planting any flowers in a pot and it isn't going over too well. First off I filled the bottom of my pot with some rocks, (it has a drainage hole), used miracle grow potting soil. In the pot I planted some mums, potatoe vines, and another flower that I forget its name. All was well but about three weeks the flowers stated to die. I feel I may have watered them too much, but I am not sure as I am new to this. I am attaching a photo.
I can imagine your disappointment, when this happened, and only three weeks after planting it up,
but I'm thinking this problem may be one of quite few things, but as this has happened so quickly, think it is more likely to be caused by poor drainage.
The symptoms of over and under watering, and that of poor drainage, visually often look very similar.
Poor drainage can be caused by, packing the compost too tightly in the pot and around the plant, but normally is caused by how well the water drains from the bottom of the pot. You pot looks to be quite a good size, which being the size that it is, would need to have quite a few drainage holes in the bottom, I noticed that you mentioned only one, which if this is the case, means that every time you water your pot, as the water is not draining properly, your plants are permanently sitting in water, which of course, is something that these type of plants don't like.
Hope this helps, as Mums are very pretty, especially at this time of year and have a long flowering period, which can be prolonged, as Jewell said by removing the spent flowers
