I have chosen flowers for a 2.5m x 1.25m bed. They are easy to germinate from seed, and some can be bought as plug plants from garden centres or by mail order. A mix of hardy and half-hardy annuals and biennial plants and a tender dahlia will give you, from late spring to mid-autumn, enough flowers to make posies and fill small vases.
Dahlia ‘Karma Choc’ x 1 (pictured above)
Cosmos bipinnatus ‘Candy Stripe’ x 2
Ammi visnaga x 2
Biennial stocks (Matthiola) x 6 – replace with dahlias in early summer.
Sweet pea (Lathyrus odoratus) x 12
Daucus carota ‘Black Knight’ x 2
Dianthus barbatus x 4
Scabiosa atropurpurea ‘Black Cat’ x 2
Narcissus ‘Tête-à-tête’ x 30 – plant these around the edge of your bed.

Photograph: blickwinkel/Alamy