There are dozens of places on the net where you can find plant correspondances, but once you know that daisies are for divination and elm trees are for faerie folk and love, what are you supposed to do with that? Well, here are some ideas:
Scent (the ever obvious one): try incense, potpourri, anointing oils, personal magickal perfume, room fresheners, massage creams, etc,.
Picking: Gathers energy
Burning: disperses energy
Burial: engenders growth or banishing
Planting: encourages maturation
Watering: provides nurturing energy
Baking: slowly increases power towards manifestation
Strewing: releasesthe plant's energy to the winds
Elementally aligned plants can be used as quarter markers for a magical circle, and branches can also be used as wands.