In Welsh tradition, marigolds were used to predict weather. Closed blossoms meant that bad weather was on the way. Open blossoms predicted fair weather.
Witches and those who practiced the healing arts wore marigolds to keep themselves safe from plague and used the blossoms to stop people from gossiping or speaking ill of others. Marigolds were also believed to encourage more cheerful conversations, and a potted marigold brought inside was thought to restore peace between a disgruntled husband and wife.
A potion made from marigold petals was also thought to summon fairies when rubbed on the eyelids of someone sleeping.
OTHER PLANT PREDICTIONS
Other plants and certain fungi such as Rainstars can accurately forecast the certainty of wet and dry weather.
Chickweed, dandelions, bindweeds, wild indigo, clovers, and tulips all fold their petals prior to the rain.
Rainstars, a type of fungus, opens up prior to a rain and closes in dry weather. Mushrooms abound when the weather is moist as well as do mosses and seaweeds.
In fact, seaweeds exposed on the rocks at low tide seem to swell and rejuvenate in the high humidity proceeding wet weather.