Much of the color in the garden through autumn and winter is provided by foliage. Some foliage turns color as the weather gets cooler. Some had been blue, gray, gold, red, bronze or variegated all year, and just happens to get noticed more now that there is not much other color provided by flowers. There are a few flowers that bloom now or even later in winter, but not nearly as many as there were in spring and summer.
Coral bark Japanese maple and red twig dogwood display colorful defoliated stems as the weather gets cooler. The colorful berries of firethorn (pyracantha), cotoneaster and toyon will ripen about the same time, providing bright red color until the birds get them. Otherwise, there might not seem to be much more to cut and bring into the home to substitute for cut flowers, and add to all the colorful foliage, twigs and berries.
Well, this is where things get less horticultural, and more creative. All those old flowers and flower stalks that should get pruned off, and maybe a few old leaves, might be good for more than compost. Blooms of hydrangea, Queen Anne’s lace and lavender can be cut just as they begin to deteriorate, and hung upside-down to dry. They lose much of their color, and shrivel somewhat, but are nice options to fresh flowers.
Old flower stalks of New Zealand flax and lily-of-the-Nile have striking form once plucked of tattered flower parts and seed capsules. New Zealand flax stalks are tall and straight. Lily-of-the-Nile stalks are like star-bursts on sticks. If the natural color lacks appeal, they can be spray painted! Seed capsules of red flowering gum (eucalyptus) dry in loose clusters with stems that are long enough to arrange like cut flowers.
Pine-cones, magnolia grenades (seedpods) and sweetgum maces (seedpods) that fall from their stems can be drilled, and attached to sticks. There are no substitutes for real flowers, but there are no limits to creative and even weird alternatives.