April is the perfect time to plant your flowering annuals and perennials in almost all United States climate zones. The only places where you should wait until later in the year are at high elevations and extremely northerly locations, where spring frosts can continue until May or June. But the rest of us can get growing in April. Bedding plants of zinnias, petunias, marigolds, phlox, snapdragons, pansies, ornamental sages and many others are readily available at nurseries during this springtime month.
Planting Flowers in April
Prepare growing beds before you purchase your flowering plants. Choose areas that receive full sun for most plants, but be aware that some flowering annuals--such as impatiens--prefer cooler, partly sunny or shady areas. Decide what type of flowering plants you want to grow and then build your beds in appropriate areas.
Weed the area or areas where you want your flowers to grow. Then dig any type of organic compost into the soil at the ratio of one part compost to four parts topsoil. If you also add peat moss or other organic materials, they will help to nourish your plants.
Dig planting holes with your trowel. Make sure they are large enough for the root systems of your plants and dig them far enough apart so plants will have plenty of space when they grow larger. Many flowering annuals need 6 to 12 inches between them.
Remove your bedding plants from their nursery pots and then gently loosen the roots, especially if they are compacted or rootbound. Then set one plant into each hole and fill in with the soil/compost you dug out. Firm it down lightly with your hand. Water well by placing a hose at the plants' bases or using a soaker hose or drip irrigation system, and continue to keep the soil moist by watering in this manner at least once a week through their summer growing season.
Fertilize your newly planted flowering plants with a slow-release or organic fertilizer that has a balanced N-P-K reading, such as 10-10-10. Most flowering annuals don't require additional fertilizer later in the season, but if you want to encourage them to produce more flowers, give them a dose of a low-nitrogen plant food, such as 0-10-10, when you first begin to see flower buds forming.