u/Heavy_Economics_8595

Just got this beauty from my college plant sale and I wanted some advice on how to take care of her. Is it kinda like taking care of a hydrangea or different?

Edit:
They told me she was a dahlia but I can’t tell…

I’ve been trying to tell my parents that mold is a very serious issue but they keep putting it aside like it’s not that important.

How can I get rid of this, it started off small and my mom would clean it, but after like two months it came back bigger and stronger.

Also I don’t really know much about mold but can someone tell me the issues it brings??