Emerald-Symbolizing love and success. A renewal stone, the emerald is thought to bestow youth and encourage rebirth (however defined). The emerald is supposedly suggested to boost intelligence and popularity, as well as protect against certain physical dangers and ailments such as poisoning. It is also good to boost travel charms, especially for those traveling by water.
Lily of the Valley-Representing sweetness, purity, honor, and humility (interestingly, so does my birth name).
Hawthornes-[One of my personal symbols, I can’t get away from the silly things] One of the fey trees, it was associated with faeries and other spirits and thusly was often talked about in a ‘proceed with caution’ sense unless you were specifically looking to invoke faerie.
Hawthornes are actually a helpful herb; the berries are used in various preparations for cardiovascular health (please see an herbalist before taking any random herb). They don’t taste unpleasant either.
Trees-Poplar, Chestnut and Ash-I’ve touched on trees briefly here.
…Unfortunately poplar is sort of a mixed bag when it comes to symbolism. It is a tree that is used as a life symbol-whoever it is also one of the death trees (which caused me to do a double take when I saw it on the list, honestly). As a modern image, the tree is often linked with lynching or gallows in lyrical symbolism. Hercules wore poplar leaves into Erebus to capture Cerebus. Take this tree as you will, it also stands for wisdom and endurance.
Chestnuts may be the truly positive member of this triad, standing for health, longevity, and abundance (but abundance sometimes in the form of fertility, so be careful how you phrase things) (and yes, it is -that- form of fertility, specifically).
Ash does a great many things, which often overlap with water symbolism (fluidity, emotion, dreaming). It is sometimes linked to women specifically.
Colors-Red and yellow or blue
Other folkloric themes to note: Beltaine falls on the 1st of May, and is the second of the spring rites-though while Ostara is the first ‘spring’ festival, I think it’s Beltaine that holds the most ‘springy’ meaning for a lot of people.