Flower Spacing Guide for Perennials
Perennials should come with information on spacing, which accounts for keeping plants healthy. Correctly spacing flowering plants will help reduce the risk of disease from poor air flow. Although it will take more time to fill the space, sticking with proper spacing will mean you won’t have to divide your perennials so soon after planting. Here are general guidelines for spacing perennials:
Small perennials – 6 to 12 inches (15 to 30 cm.)
Medium perennials – 12 to 18 inches (30 to 46 cm.)
Large perennials – 18 to 36 inches (46 to 91 cm.)
Flower Spacing Guide for Annuals
The space between flowers is a little less important for annuals. These plants will only last one growing season, so you can cram them in a little tighter. However, if given the right conditions, your annuals planted with the appropriate spacing will fill out in plenty of time to enjoy big clusters of flowers all summer. For planting annuals, follow the guidelines that come with the plants. Here is the spacing information for some of the more common annuals:
Begonias – The tubers of begonias should be 8 to 12 inches (20 to 30 cm.) apart.
Cockscomb (Celosia) – Plant cockscomb about 8 inches (20 cm.) apart.
Cosmos – Give cosmos flowers at least 7 inches (18 cm.) between plants.
Dahlia – Many types of dahlia grow quite large and tall and form almost a hedge of flowers. Give them two to three feet (0.6 to 0.9 meters) of space to fill in.
Geraniums – There are a few types of annual geraniums with different spacing needs. The most common, zonal, need about 12 inches (30 cm.), while ivy geraniums need up to 36 inches (91 cm.) of space.
Impatiens – Space impatiens 8 to 12 inches (20 to 30 cm.) apart, closer if you want them to grow taller.
Lobelia – The petite lobelia flowers need just 4 to 6 inches (10 to 15 cm.) of space.
Marigolds – Plant smaller varieties of marigold 8 to 10 inches (20 to 25 cm.) apart and larger types up to 12 inches (30 cm.) apart.
Pansies – Give pansies 7 to 12 inches (18 to 30 cm.) of space, a little less if planted later in the fall.
Petunias – Different petunias have different spacing needs. Give grandiflora petunias 12 to 15 inches (30 to 38 cm.) and multiflora petunias 6 to 12 inches (15 to 30 cm.).
Snapdragons – Space your snapdragons 6 to 10 inches (15 to 25 cm.) apart.
Zinnias – Spacing for zinnias varies a lot depending on the variety, so check your plant information. Spacing is anywhere between 4 and 24 inches (10-61 cm.). Rows should be 24 inches (61 cm.) apart
Any of your annuals can be planted closer together when placed in containers.
