Annual and Perennial Flowers: Planting Procedures and Plant Recommendations
A good way to begin planting annual and perennial flowers is to create islands of flowers in an open lawn, but because such beds are easily viewed from many sides, they often require high maintenance to keep them attractive.
Border plantings along a wall, fence or hedge can soften the transition of landscape structures into the rest of the landscape or can create alleys of color. Rectangular beds lend themselves to a border planting where space is restricted. When planting a perennial border against a hedge, fence or wall, leave a little space between the border and its backdrop. This spacing allows for better air circulation, more light penetration and ease of maintenance from the rear of the bed. Perennial borders often are 6-feet to 8-feet wide, allowing adequate space for at least a combination of six or more species, front to back, yielding a continual blooming period.
To prevent turfgrass from growing into the perennial bed and becoming unsightly, use some form of broad edging or separating strip. Bricks laid flat, flagstone, bare ground or a heavy layer of mulch such as pine straw or pine bark will help keep out grass.
Annual and perennial flowers may be grouped according to color, intermixing plants that bloom at different intervals for a continual display. Plant height is a major consideration also. In border plantings, the tallest plants are usually placed toward the rear to serve as a backdrop with a few moved forward to prevent monotony in the design. In island plantings, they are placed toward the center. Fall-blooming perennials are usually
the tallest, making them the best backdrop or accent plants. Most of the middle
height perennial plants are summer bloomers and may occupy the majority of the
middle space. Spring-blooming perennials are primarily short plants; place them toward the front.
Emerging foliage and flowers of later-blooming plants can help hide the fading foliage of earlier flowers. Narrow beds with excessively tall plants are usually not effective displays. Whether for borders or island beds, keep the width of a planting about twice the height of the tallest plant.
More than 80 percent of bedding plants sold for landscape use in Louisiana are classified as warm-season annuals. Major warm-season bedding plants include ageratum, begonias, cockscomb (celosia), coleus, impatiens, marigolds, periwinkle (vinca), petunia, portulaca, purslane, salvia and zinnia. Some other warm-season bedding plants, such as sunflowers, torenia (wishbone flower), geraniums, gomphrena and melampodium are available, too.
Pansies dominate the cool-season bedding plant market in Louisiana. Other major cool-season bedding plants include dianthus, snapdragons, viola and ornamental kale/cabbage. Alyssum and stock are two cool-season bedding plants growing in popularity.
Probably the key best management practice that should be used in Louisiana regarding annual flowers in landscapes is the proper use based on the purpose and site location.
|
Shady Locations
Begonia
Coleus
Impatiens
Torenia
Caladiums
|
Container Plantings
Begonias
Periwinkle
Petunias
Coleus
Pansy
Viola
French Marigolds
Torenia |
Edging Borders
Ageratum
Cockscomb
Alyssum
Begonia
Dianthus
Dusty Miller
French Marigolds
Pansy
Petunia
Portulaca
|
|
Hanging Baskets
Alyssum
Impatiens
Petunias
Purslane
Portulaca |
Hot and Dry Locations
Periwinkle
Melampodium
Cockscomb
Zinnia
Purslane
Portulaca |
Fragrant Flowers
Alyssum
Flowering Tobacco
Petunia
Stock
Dianthus |
Flowering perennials are plants that live for several years and often require two or more years from seed to flower. There is a renewed interest in herbaceous perennials because they need less maintenance, less water and fewer pesticides than annuals. Many gardeners include flowering bulbs and ornamental grasses in this category. Once prominent in many landscapes, these enduring plants are being rediscovered for their dependable seasonal effects. Unlike trees and woody shrubs, which are also perennials, herbaceous or flowering perennials are those that appear to die down part of the year, only to emerge again the following season from underground roots, stems, bulbs or rhizomes. The simple term “perennial” is commonly used when referring to herbaceous perennials.
Perennials are easily used as ground covers, mixed with annuals, grown in containers and used as accents or specimen plants. Many perennials are short bloomers and are best mixed with others that bloom at different times or included with other landscape plants as part of an overall design.
Consider the site before selecting your plants. Although many perennials, such as ferns, tolerate heavy shade, most perennial plants require abundant sunshine. Air circulation is important for avoiding diseases; stagnant, warm and humid air creates ideal conditions for diseases. Perennial plants also require properly prepared soil, and a few have specific drainage and fertility requirements.
Though most perennials may take a couple of years to flower from seed, many are as easily started as annuals. The quickest way to have blooming plants, however, is by vegetative propagation, such as by dividing old plants or rooting stem cuttings. Plants produced vegetatively have all of the traits of the “mother” plant. Propagation by division may seem difficult at first, but most gardeners find that dividing crowns and roots and separating bulbs takes very little experience and can be mastered quickly. Try dividing monkey grass for experience, then move on to daylilies, and, before long, you will have the hang of it.
Perennial plants with shallow roots are easily pulled apart by hand. Long, fibrous roots can be pulled apart with a hand fork. Thickly intertwined roots may need more forceful separation or cutting with digging forks. Replant only those segments with strong roots and a few intact leaves or crowns.
In general, it is best to divide perennials during their dormant or “off” season; divide spring bloomers in the fall and fall bloomers in spring. Some perennials may need dividing every three or four years, or they will slowly crowd themselves into clumps of nonflowering leaves and roots.
Many perennials may be propagated from stem cuttings, which does not disturb the plants’ roots. Take stem cuttings during the spring or early summer, choosing stems that are mature and firm but not yet hardened and woody. Cut off 4-inch to 6-inch segments using a sharp knife or shears, and pinch off the succulent tip and any flower buds to force the cuttings to concentrate their energy on producing roots. Remove the lower leaves that will be below the surface of the rooting medium, but leave a few leaves to provide a source of energy for root initiation and growth.
Perennial flowers for Louisiana include lantana, perennial verbena, butterfly bush, perennial salvias, cannas, purple coneflower, shasta daisy, rudbeckia, daylilies and Louisiana iris.