Ideas for upright flowers to bloom around Mother's Day?

Okay, I know this is kind of a weird thread title so here's what I'm doing. I volunteer in the elementary school and each month I present the work of an artist in history. I try to make this really fun and interesting to keep the kids involved and learning.

This month is "Cave Art". I thought it would be neat to have the children do Cave Art drawings on some type of ceramic pot. Then, I could bring them home and plant something in them in time for something to bloom around Mother's Day. I need an upright flower so that the children's art on the pot is not hidden by a vine type of flower.

Does anyone have any suggestions? Also, any ideas on the best type of pot to use? Should I spray paint the pots before they do their work? Any and all ideas are appreciated since I'm just brainstorming this one.

Thanks :)