The purpose of foundation planting has traditionally been to hide a building's foundation, a necessity for mid-20th century homes with their poured concrete foundations. Many modern homes lack this feature, however. Today, foundation plantings have become part of a larger landscape scheme called "curb appeal." The best foundation plants do not merely hide a plain foundation or soften the edges of the building; they help focus attention on the entry to the home.
How the Best Plants Function
The best foundation plants function as part of a whole picture. They soften the edges of the house and often extend away from the building to define the edges of the property itself. Taller plants should be placed on the edges of the composition; mass smaller shrubs like azaleas, sweet fern or potentilla near the home's entrance to direct and brighten the way. Use odd-numbered groups of shrubs, and mix evergreen shrubs with deciduous shrubs for seasonal interest. Compose blue junipers with Japanese maple, crape myrtle and lacecap hydrangeas for four-season interest. Limit your use of color in your public landscape; interplant perennials for color or ornamental grasses as accents.
Use small trees or tall shrubs that do not block sight lines to the entrance or windows of the house for accents in foundation plantings. Plant arborvitae and taxus that will not outgrow their space as adults. Pieris Japonica, Blue Girl holly and mountain laurel, all evergreens, grow to 10 feet tall. Dogwood, flowering crabapple and star magnolias all provide spring bloom interest. Guajillo grows 15 feet tall with fern-like leaves and cream-colored flowers; the catclaw acacia has delicate foliage and sets seeds that look like peapods. Collections could include groupings of shrubs with a small tree or collections of the same species of shrub, like mallow, hollies, Manzanita, ceanothus or other dogwoods, in assorted sizes and colors.
West Coast gardeners grow a compact bamboo called nana papurea with summer flowers and purple fall foliage. "Wynyabbie Gem" westringia, notable for its long-lasting purple flowers and India hawthorn, are salt-resistant. Loropetalum "Rubrum," boxwoods and rhododendrons are evergreen in many areas. Viburnum varieties and witch hazel provide spring blooms. Buckeyes, chokeberries and Japanese barberry have brilliant fall foliage. Summersweet is a hardy summer bloomer. Butterfly bush comes in lavender and bright orange-flowered varieties but may be invasive in some areas. Oakleaf hydrangea tolerates more shade than many varieties, and peegee hydrangeas are more compact for grouping. Use Betty Prior and Knock Out roses for foundation plantings in Midwest cottage gardens; use English roses in Northwest or Southern plantings.