Gosh, there are so many great 'summer' appropriate fragrances. Here are just a few ideas.
There are quite a few fans of Summer by Kenzo (or SummerByKenzo). It has Almond/heliotrope notes that are very pretty.
I love Hermes Un Jardin Sur Le Nil for the green mango note.
Flowerbomb is beautiful, and in my mind anyway is a year round scent (and you say she liked the sample she tried).
I think of green tea scents as warm weather scents, and my favorites of those are Elizabeth Arden Green Tea (which can be had for a song), and Bvlgari Green Tea Extreme.
Just a few ideas to get you started! Good luck!