‘If we now wished to go still further, we would have to find, if the previous considerations are correct, that through this surrender of the earth to the sun, the plants somehow express how the earth, through what it brings forth, really lives in the great macrocosm. We would have to perceive some thing in the plants, so to speak, which would indicate to us that something works into the plant world that is brought about outside especially by the sun being. Linnaeus pointed out that certain plants open their blossoms at 5 a.m. and at no other time. This means that the earth surrenders itself to the sun, which is expressed in the fact that certain plants are able to open their blossoms only at very specific times of the day; for example, Hemerocallis fulva, the day lily, blossoms only at 5 a.m.; Nymphaea alba, the water lily, only at 7 a.m., and Calendula, the marigold, only at 9 a.m. In this way we see a marvelous expression of the earth’s relationship to the sun, a relationship that Linnaeus termed the ‘sun clock.’ The plant’s falling asleep, the folding together of the petals, is also limited to very specific times of the day. A wonderful lawfulness and regularity is evident in the life of plants.’ (Rudolf Steiner.)
Marigold (calendula) is use as a medicinal herb; here’s a plant promotion video by Weleda on YouTube. There’s talk about vitality and forming forces. Marigolds are also nice to grow, even in pots in the city. Their colour is cheerful.