I LOVE daffodils - inexpensive - they look pretty when planted together (rather than six-eight inches apart) and will multiply as the years pass while other bulbs are less prolific as time goes by. Plus, they're an early bloomer, so it's nice to have some color as winter is fading away. I like the little tete a tete ones that bloom very early and have multiple blooms on the stems, as well as the more traditional varieties.
I did a "memorial garden" in the front of my home for one pet and in my back yard for another ...
... and then kept on going as I enjoyed it more and more ... now have more than I can handle! A pretty shrub that has a very fast growth rate is a dappled willow - very pretty light green/cream/pink leaves to start the spring. Daisies will bloom in the late spring right on into the late summer. A burning bush will be just green all year until the fall and then be a blaze of small red leaves for a few larger ideas. If you're wanting it to be peaceful, maybe try all greens and whites, or something along those lines, too... GOOD LUCK!