I love the idea of recycling greeting cards once they have been taken down from the mantlepiece. These cards from Arbee Cards are actually plantable.
The plantable paper is handmade from cotton (tree-free!) and is UK-made (no travel - low carbon) and contains a mix of wildflower seeds which look like small black specks in the paper: Catchfly, English Daisy, Sweet Alyssum, Snapdragon, Corn Poppy and Black Eyed Susan.
The entire card is planted in soil or compost (patio pot, windowbox or garden bed) and must be kept moist and preferable in a sunny spot and should germinate in a few weeks. The paper itself breaks down in the soil and is bleach-free and completely eco-friendly. The card has a textured side from the process of handmade paper-making, with the upside of the paper feeling like a heavyweight artists' paper.
As Rachel Law of ArbeeCards said "I use it for making cards & wedding stationery. Mother's Day plantable cards were so popular with people just loving the idea of posting their mum some flowers for her to grow. They are becoming increasingly popular for weddings, with plantable place cards doubling as favours - people get some lovely flower seeds for the garden to take home instead of wasteful expensive favours, keeping everything environmentally-friendly. Really, who needs more sugared almonds in a chiffon bag! I try to encourage couples to make their white wedding green - and much of my cards & stationery is recycled card, upcycled vintage papers, buttons, lace and re-used cards & papers'.