One great thing about Seattle is that spring starts early and it goes on and on (until the fourth of July really.) So we've got many flowers blooming right now. Introduce the wonder of buds. Bring branches inside from the neighborhood. Especially from trees and bushes that can be seen by your child from a window, even the car. These trees were bare a few weeks ago and Look! Camillias are large and can withstand a lot of toddler handling. Azaleas are abundant, so bring in enough to explore. Allow him to peel them open and crush them. Give him an unbreakable vase with water for his flower. Save some that you witness open in the next few days. If you bring in a branch of cherry or plum blossoms, explain the cycle of bud, blossom, fruit, (or just sing a silly song with those words.) Pussy willows are a favorite at this time too. My daughter spends time picking the fuzzy orbs off of her branches and collecting them in a bowl.
What a wonder!