Having a plan before you plant is key to creating a beautiful flower garden. It's much easier to change the garden design and move plants on paper than to dig up everything in the garden later because a plant grew larger than you expected or you discover that flower colors clash.
Before you start digging up your yard or tearing out old landscape beds, consider the location. Make a sketch that shows the location of existing structures, such as your house and garage, and all plants you want to leave in place, such as trees and shrubs. It can be either a quick sketch to give you a rough idea of what goes where or a detailed layout on graph paper with, for example, 1/4 inch on the paper equal to 1 foot in the yard.
Make notes, either on your sketch or separate paper, of the sun and shade conditions in your garden location. They will help when you select plants for different spots in the garden. A location that receives six or more hours of direct sunlight each day is in full sun. A partial-sun location gets three to five hours of direct sun exposure each day. A partial-shade location receives a few hours of dappled sunlight daily. An area in full shade never gets direct sunlight.
Note soil conditions in the location as well. If it has sandy, well-drained soil, then look for drought-tolerant plants or plan to add soil amendments. Plants that require a lot of moisture need places where the soil stays moist, such as at a slope's base.
Slopes also affect landscape design. A flat location and a gentle slope are the easiest places to plant a flower garden. A steeper slope may need terraces or plants suitable for erosion control.
Lay out Plants
Once you know exactly where you will plant, the next consideration is what plants to put where. A narrow flowerbed -- usually 2 to 3 feet wide -- needs small plants that won't crowd each other. A bed at least 6 to 8 feet wide can accommodate a mixture of large plants, which add height and take up space, and smaller plants to fill spaces and grow near the bed's edges. Ensure every perennial plant you choose is hardy in your U.S. Department of Agriculture plant hardiness zone. Perennial plants live more than one year, annual plants live only one year and biennials live two years.
Check the mature height and spread of every plant you want in your flowerbed before you plant. Space perennial plants far enough apart to accommodate their mature sizes. As a general guideline, space tall perennials 18 to 36 inches apart, those with an intermediate height 12 to 18 inches apart and dwarf plants 6 to 12 inches apart. While you wait for the perennials to fill their spaces, an option is to plant annuals around them for the first one or two years. You can also leave spaces in your garden design if you want to plant annuals every year.
Place tall plants near the back of a bed that has only one open or accessible side, with a fence or building as the bed's backdrop. If a bed can be accessed from all sides, such as an island bed surrounded by lawn, then place tall plants near the bed's center. Mixing those guidelines a little can create visual interest, but usually avoid placing tall plants near the garden's edges or short plants in its back and middle.
Plan for Year-Round Interest
It's simple to plan a flower garden around favorite plants only to realize part way through the year that they have a limited bloom time, wilt in heat or provide no winter interest. Planning a garden that looks good year round takes more time, but it's worth that time in the long run.
Early-blooming bulb varieties are often the first plants that come to mind for spring flowers, but add plants for later spring interest as well.
- Large-cupped daffodil (Narcissus 'Ceylon', USDA zones 3 through 8) are bulb plants that flower in early spring. Like most other spring-flowering bulbs, it grows best in well-drained soil, and it thrives in a full or partial sun.
- Common garden peony (Paeonia lactiflora, USDA zones 3 through 8) is a herbaceous, clumping plant that grows 1 to 3 feet tall and blooms in late spring or even summer in some locations. It prefers full sun or partial shade in moist but well-drained soil rich in organic matter.
Many popular perennials bloom in the summer months. Often, the challenge is narrowing their selections rather than trying to find plants that bloom in summer.
- Black-eyed Susan (Rudbeckia hirta, USDA zones 3 through 7) flowers from summer to fall. It grows 2 to 3 feet tall and spreads easily. It does best in full sun and tolerates most well-drained soil types.
- 'Stella de Oro' daylily (Hemerocallis 'Stella de Oro,' USDA zones 3 through 10) is a tough, simple-to-grow plant that does best in full sun and moist, fertile soil. This cultivar has bright-yellow blooms from late spring through early fall.
- Purple fountain grass (Pennisetum setaceum 'Rubrum,' USDA zones 9 through 11) is grown as an annual in areas cooler than its USDA hardiness zones. Its reddish-brown foliage lasts throughout the growing season, and its rose-colored flowers appear in summer. This plant grows 4 to 6 feet tall and 2 to 4 feet wide. It does best in full sun and tolerates a range of soil conditions.
Some summer-blooming plants continue blooming into early fall, at which point fall-blooming plants and shrubs with showy autumn colors can take center stage in the garden.
- 'Bedazzled Bronze' garden mum (Chrysanthemum morifolium 'Bedazzled Bronze', USDA zones 5 through 9) is often planted in fall as an annual and flowers until frost. It grows about 2 to 3 feet tall and wide, and it does best in well-drained soil and full sun.
- 'Winterthur' smooth witherod viburnum (Viburnum nudum 'Winterthur,' USDA zones 5 through 9) is a shrub with red foliage in fall and clusters of berries that start out pink in summer and turn blue in fall. The 'Winterthur' cultivar grows 3 to 6 feet tall and wide, and prefers moist soil in full or partial sun.
Choose evergreens or plants with an interesting shape to add interest to the flower garden during winter months. Some plants bloom during winter, even in cool climates.
- 'Angelica Blue' juniper (Juniperus chinensis 'Angelica Blue,' USDA zones 4 through 9) is an evergreen shrub that reaches 3 to 5 feet tall and 5 to 10 feet wide. It grows best in full sun and well-drained soil. Its blue foliage lasts all year, and the color intensifies in cold weather.
- Harry Lauder’s walking stick (Corylus avellana ‘_Contorta,’_ USDA zones 4b through 8) features twisted branches that are most visible after the leaves drop in fall. This shrub grows 5 to 10 feet tall and 8 to 12 feet wide. It tolerates a range of soil conditions and prefers partial sun or partial shade.
- Lenten rose (Helleborus x hybridus, USDA zones 4 through 9) grows best in a shaded location with even soil moisture. It blooms very early in the year, often when snow is still on the ground. It grows 15 to 18 inches tall and spreads as a ground cover.
Most garden plants, especially perennials, grow best in well-drained soil rich in organic matter. As a general rule, work organic matter into the soil before planting. Doing that task the fall before spring planting is best, though you can amend soil right before planting. Spread a 1- to 2-inch layer of organic matter -- such as well-rotted compost, leaf mold or peat moss -- over the soil, and work it into the soil to a depth of 6 to 8 inches.
Perennials and annuals purchased in pots can be planted anytime during the growing season. A typical guideline is to plant after your location's last average frost date in spring, and avoid planting so late in the year that the plants don't have time to establish good root systems before winter. Early spring or fall is the best time to plant shrubs and trees, and spring-blooming blubs are usually planted in fall.
Water plants' soil thoroughly after planting. For the first couple weeks, water every two days if no rain falls. Gradually decrease watering to every four to six days during the next few weeks. Afterward, water as needed for specific plants; check their nursery tags or labels. If you plant during hot weather, the plants will need more frequent watering.
Place mulch on the planted flower garden's soil surface to discourage weeds, insulate plant roots and hold in moisture. Choose an organic mulch such as wood chips so soil fertility will improve as the mulch decays. Apply small wood chips or shredded wood in a layer 1 to 2 inches thick, or use larger chips in a 3- to 4-inch layer. Do not let the mulch touch the bases of the plants, or else diseases could develop.