A winter flower garden is possible in hardiness zones not subject to hard freezes on a regular basis, such as zones 9 through 11. If you live in zone 8 you still might be able to create a winter flower garden by selecting the right location for the garden and flowers. Another option is growing the flowers in containers which can be moved inside when bad weather threatens or grouped together and protected from frost.
Select a protected location where the garden is shielded by walls or fences which retain heat. A western or southern exposure works well. The garden must receive at least eight hours of sunlight a day. This is even more critical in winter since the sunlight isn't as strong as in summer. Dig the soil and amend with organic materials.
Choose the flowers. Hardy annuals and perennials can handle a few degrees below freezing as a low temperature but not on a constant basis. Half-hardy flowers will live through a light frost but not much below freezing. Cool season flowers like pansies, nasturtiums, stock and snapdragons are good choices. Blooming spring bulbs are available in florists and the floral department of grocery stores in late fall through the holidays and Valentine's Day.
Start the seeds inside or purchase plants from the nursery. Seeds take longer to germinate in cool soil. Put new potting soil in compressed peat moss pots. Water the soil until it's soaked and the pot is damp as well. Place three seeds in each pot about an inch apart. Cover the seed with an 1/8 inch of soil and mist with water. Place in a sunny window or under grow lights. Thin to the two strongest seedlings and then to one.
Harden the seedlings before planting in the garden. Bring them outside for a few hours the first day, lengthening the period by two hours each day until they are outside the entire time. Don't remove the plant from the peat pot. The pot will disintegrate.
Plant the taller flowers in the back of the winter flower bed. Place flowers that vine a bit at the sides to soften the edges. For example: Plant stock and snapdragons in the center, and put pansies in front of the stock and snapdragons. Plant nasturtiums around the edges.
Protect the flowers from frost by covering each one with a glass or plastic jar, removing it during the day. The bed may also be covered entirely in plastic and a sheet. Prop up the ends of the material along the edges of the bed with sticks. Remove during the day.