Certainly, here's a list of 15 flowers you can consider giving your girlfriend to express your love and affection:

1. Red Roses: The classic choice for conveying deep love and passion.

2. Pink Roses: Symbolizing admiration and gratitude, pink roses are a sweet and romantic option.

3. White Roses: White roses represent purity and innocence, making them a great choice for new or pure love.

4. Yellow Roses: These bright blooms represent friendship and happiness, perfect for a cheerful gesture.

5. Orange Roses: Orange roses signify enthusiasm and desire, making them a bold choice for passionate love.

6. Purple Roses: A symbol of enchantment, purple roses are ideal for expressing love at first sight.

7. Lilies: Lilies symbolize purity and devotion, making them a classic choice for expressing deep love.

8. Tulips: Red tulips represent true love, while pink tulips convey affection and caring.

9. Orchids: Orchids symbolize love, beauty, and strength, making them a sophisticated choice.

10. Sunflowers: These vibrant blooms represent adoration and loyalty.

11. Daisies: Innocent and charming, daisies symbolize purity and love.

12. Carnations: Red carnations represent deep love and admiration, while pink ones symbolize gratitude.

13. Peonies: A symbol of good fortune and happy relationships, peonies make a romantic gesture.

14. Gerbera Daisies: These colorful and cheerful flowers symbolize happiness and innocence.

15. Freesias: Freesias represent trust and friendship, making them a great choice for a meaningful bond.

When choosing flowers for your girlfriend, consider her personal preferences, favorite colors, and the meaning behind each type of flower. A beautifully arranged bouquet of any of these flowers can be a thoughtful and romantic gift to show your love and affection. Don't forget to include a heartfelt note or message to make the gesture even more special.