Pearl-Symbolizing purity, including an increase in health and other types of physical purity and perfection. Also good for money, general luck, and love luck.
The flower has a deep connection with love and romance, being the flower of Aphrodite/Venus. I think that it’s interesting however that a lot of modern writers and poets associate her with something much closer to the ideal of courtly love than perhaps what she was actually good at-hers was a love that quite fine with the idea of rampaging.
The rose holds several layers of meaning. There are historical examples of the rose actually standing for secrecy as opposed to love. The symmetry of the rose has long been appealing to religious writers of various faiths who use the flower to express the concept of divine love and protection; the connection to the divine has also led to a perhaps increasingly archaic belief that deity smells like roses and a successful exorcism will smell like such.
Trees-Oak and Fig-I’ve touched on trees briefly here.
Oak has a slightly more positive association than the May trees. Oak represents wisdom, power, and creativity.
Fig is another wisdom tree and is connected to both Demeter and Dionysus.
Colors-Red and yellow or white
Other folkloric themes to note: Litha/Midsummer falls on the first day of summer and marks the first early harvest/last planting and full movement into the growing season.