Flower beds make a great addition to any yard. Flower gardens have few rules and allow creativity in your landscape design. They provide color and texture to the landscape, while providing valuable pollen, seeds and nectar for bees, butterflies and birds. Flower beds vary in size depending on their purpose, the types of plants and your needs.
Types of Flowers
Before planning the size of the flower bed, consider what types of flowers you want to grow. Annuals need more access for planting and removing them each year, but require little maintenance aside from watering and occasional weeding. Annual flowers tend to work best in narrow beds 3 feet wide, but no more than 5 feet wide. This allows you to reach to amend the soil and plant seeds or plants without walking in the bed.
Perennials will grow and fill in a bed when properly spaced, meaning less weeding and exposed soil as they mature. A perennial bed plan needs to fit the mature sizes of the plants. For example, a large flowering perennial with an expected 3-foot spread will look out of place in a bed smaller than 3 feet wide.
Flowering shrubs have some maintenance needs and can take up a lot of space in the flower bed, especially as they mature. A flower bed that includes shrubs will need to accommodate the extra space for growth and an additional 2 feet of space between the flowering shrub and other plants.
Flowering bulbs make a great border with any type of flower bed, or provide color when your other flowers aren't blooming. Bulbs that need to be removed and stored during winter months have the same consideration as annuals -- a narrow, 3-foot-wide bed works best. Bulbs that stay in the ground the year around fit in almost any size of flower bed.
Scale of the Bed
When designing your flower bed, consider the scale of other features and the size of the flowers. For example, a large island flower bed 4 feet wide and 8 feet long would overwhelm a small front yard and a small home, but look balanced in a large suburban yard or backyard. A large yard will also handle more than one flower bed. A 3-foot-wide border along the fence and a small 4-foot island work together well if you have enough space between them.
Plant height also affects the size of the bed. Taller plants need a wider bed for proper scale. The plants' height should not exceed two-thirds of the bed's width. For example, if you want to grow 4-foot-tall flowering perennials, they need a bed at least 6 feet wide.
Types of Flower Gardens
The size of your flower garden depends largely on the type you want. A perennial border bed along a fence or structure will only have a width of 2 or 3 feet, but a length as long as needed. The bed's narrow width allows for easy access to all of the flowers and doesn't overwhelm since it is meant as a border. An island or raised bed typically has a shorter length and more width, but unless you have a path to reach all of the plants, it shouldn't be wider than 4 feet to allow for access. A cottage or English flower garden might reach 8 feet wide to accommodate shrubs and larger perennials.
Time for Maintenance
Maintenance of the bed is an important limitation on size. You'll need to ask yourself how much time and energy you have for maintaining the flower bed. A flower bed will require regular weeding, watering, pruning, fertilizing and mulching.
If you have little time, opt for a with only a few varieties of plants. If you know up front that you want a larger bed and have the time to maintain it, opt for a cottage garden or elevated island bed that has space for many types of flowers. A cottage bed might be only 6 feet wide and long, or take up the whole yard. Either way, you'll need a path or stepping stones to reach all of the flowers.