I don't just use fresh flowers for creating displays in the house. I seem to have an ever-growing collection of dried flowers and seed heads - giant, starry Allium christophii heads, sculptural opium poppies and the balloon-shaped heads of Nigella (love-in-a-mist). The good thing about them is that you can just chuck them on the compost heap if you tire of them or they get really dusty and grab yourself some fresh ones. Alliums come back every year and are best left to dry on the plant and then harvested before they get too weather-beaten. Poppies self-seed so you can have fresh seed heads each year and once you've grown the prolific self-sower love-in-a-mist, you'll be hard-pressed to get rid of it from the garden. Don't worry, it's easy to weed out or move seedlings if they pop up in the wrong place.
Alliums look fabulous just on their own in a single-stem vase or vintage glass bottle. You can even suspend them from the ceiling at Christmas-time, spraying them silver or gold if you're feeling adventurous. You'll find information on drying seed heads here.
I also grow a range of flowers that are suitable for drying. My favourites are Helichrysum or 'everlasting flowers'. They come in a wide range of colours and retain their colour and shape perfectly. You can use them as fresh flowers, dry them with the stems for display in a vase or use them for decorating dried flower wreaths or for adding a splash of colour to your Christmas wreath. I'm a fan of having wreaths on the wall throughout the year.
The best flowers for drying are those that retain their colour once dried. Varieties with thin petals and single flowers will dry quickly and successfully. Examples are larkspur, feverfew, sea lavender (Statice) and winged everlasting (Amobium alatum). Grasses like bunny's tails (Lagurus ovatus) also dry beautifully.
How to dry flowers:
Bundle together small bunches (about 8-10 stems) and tie them at the bottom of the stems using a piece of garden twine about 20 - 30 cm long.
Make a loop at the other end of your twine and use it to hang the flowers upside-down somewhere warm and dry in the dark. I use what used to be an airing cupboard but you could use a garage or something similar.
Leave until all parts of the flower are completely dry (usually about 1-2 weeks depending on the flowers used).