Whether you grow annual or perennial flowers, the bed in which you plant the flower garden must be prepared early each spring for a successful summer growing season. Preparation for next year begins in the fall after the gardening season winds down, and is finished just prior to annual planting in spring or when perennials begin to reawaken as the weather warms up. Preparing the flower garden properly keeps the soil healthy and helps head off disease and insect problems, especially in perennial beds.
Pull up all the withered annual flowers in fall once they finish blooming. Cut back perennial flowers with gardening shears to within 2 inches of the ground once their foliage yellows and dies back. Remove all the spent plant materials from the garden and compost or dispose of it.
Lay a 4-inch layer of straw mulch over the garden bed once the ground begins to freeze in late fall. Winter mulches protect perennial plants from the cold, as well as prevent early weed growth in spring in annual gardens.
Remove the straw in spring when perennial flowers begin growing or just prior to planting annual flowers. Rake up any leaves or garden debris that built up on the bed over the winter.
Fertilize perennial beds in spring with the type of fertilizer and the amount recommended for the particular plant type. Fertilize annual beds with a 10-10-10 (nitrogen, phosphorus, potassium) analysis fertilizer applied at a rate of 2 pounds per 100 square feet of garden.
Apply a 2-inch layer of finished compost on top of annual beds and till it and the fertilizer into the soil to a 6 to 10 inch depth. Add a 1-inch layer of compost around the plants in perennial beds and water afterward. Compost adds organic matter and nutrients to the soil while improving drainage.