A simple card, even on handmade on the computer would be nice. A nice quiet dinner out of the house is sometimes nice, or even a candle light dinner at home.
Natural or regional flowers would be obviously difficult in the winter. V-day should be moved to April or May, but even then the only flowers might be crocuses.
I would prefer to give potted flowers for planting in the garden.
Here's a nice, natural one that resides in a pond/lake a few miles from my house.