They mean here is a heart that is the colour _____. They don't have meaning. I use all the coloured hearts when I'm sending super gay messages to my super gay friends. We send each other rainbow heart messages whenever we're talking about gay shit.
Calendula is a plant. The flower is used to make medicine. Calendula flower is used to prevent muscle spasms, start menstrual periods, and reduce fever. It is also used for treating sore throat and mouth, menstrual cramps, cancer, and stomach and duodenal ulcers. Early research suggests that applying a specific gel (Estromineral Gel, Rottapharm-Madaus) that contains calendula, Lactobacillus sporogenes, isoflavones, and lactic acid to the vagina for 4 weeks reduces symptoms of vaginal atrophy such as vaginal itching, burning, dryness, and pain during intercourse. 2  Leg ulcers.
When looking for an herbal remedy to treat skin or wounds, think flower power -- or, more specifically, calendula. Its flowers, and occasionally its leaves, can be used to treat a variety of afflictions in different ways. Calendula has a long history of use as a wound-healing and skin-soothing botanical.