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Perennial plants are the backbone of nearly every flower garden. Unlike annual plants, which must be replanted each spring, herbaceous perennials die to the ground at the end of the season, and then regrow from the same roots the following year. People grow perennial flowers because they are such easy-care, dependable performers, and because they offer an enormous variety of color, texture and form. Here are the basics of garden design, plant selection and care.
The lifespan, bloom time, culture and form of perennial plants varies greatly. Some species, such as lupines and delphinium, are so called "short-lived" perennials, with a lifespan of just three or four years. Others may live as long as fifteen years, or even, in the case of peonies, a lifetime. Bloom time may last for only two weeks each year, or may extend over two or three months.
Some perennials, such as primroses, require deep humusy soil and plenty of shade, while others such as threadleaf coreopsis and cushion spurge wither away unless they grow in well-drained soil and full sun. Some perennials contain themselves in a nice, neat mound, while others, such as gooseneck loosestrife, will take over your entire garden. Some species should be cut back in midsummer, while others, such as hybrid lilies, may die if you remove their foliage.
There are so many different species and cultivars of perennial flowers to choose from that few people ever become completely familiar with all the options. For the perennial gardener, books are an invaluable resource. They provide photographs for identification (and inspiration!), cultural information, a description of growth habits, bloom time, color and characteristics of special cultivars. Invest in a good how-to book that has cultural information, and a color encyclopedia to help you identify plants and plan your selections.
Fellow gardeners are another great source of information about perennials. They can give you firsthand details about bloom time, height, hardiness and cultural requirements, and, if you visit their gardens, you can also see for yourself what the plants really look like up close. Nothing beats seeing a plant in a garden setting, where you can observe how it is being used. You may even go home with some pass-along plants for your own garden.
There's just no way to know how a plant will do for you unless you give it a try. If it turns out to be too tall, the color is wrong, or the plant doesn't thrive, you can always move it and try something different.
Few if any "perennial gardens" contain only herbaceous perennials. Woody plants, such as shrubs, roses, and trees, are often incorporated to provide a backdrop for the perennial plants, or are used to fill in and give mass to the bed or border. Many gardeners include annuals or biennials in their perennial gardens to provide splashes of dependable color throughout the season. Bulbs are added for early spring color and ornamental grasses for their interesting textures and late-season beauty.
Traditionally, perennial gardens have been laid out in one of two ways: a border or an island bed. A border is typically a long, rectangular flower bed that is about two to four feet deep. The classic English perennial border, which was so popular in the first half of the 20th century, was often as much as eight feet deep and 200-feet long. But for most home gardeners, a better size is about three feet deep and about 12 to 15 feet long.
Borders are usually viewed from only one side, and are located in front of a backdrop. This backdrop may be created with shrubs, a hedge, a fence or a stone wall. A well-defined front edge is important. You may design a solo border, or a matched pair. When selecting plants, keep in mind that borders usually look best when there is a repeating theme of plants and colors.
An island bed is a garden that floats in a "sea" of lawn. The shape is irregular, with gentle curves and no sharp corners. It is usually designed to be viewed from all sides, with the tallest plants positioned along the center line of the bed, and the shortest plants around the edges. Island beds look best when they are generous in size. A good size for an island bed is 8-by-15 feet, with the tallest plants reaching a height of about five feet.
Of course perennial flower gardens sometimes look nothing like a traditional border or island bed. Rock gardens break all the rules, for the objective is usually to create an irregular, natural-looking rock outcropping where tiny alpine plants can be featured.
Shade gardens are often irregularly-shaped, because they follow the natural shade patterns of the trees above. Another emerging style for perennial gardens is the large, free-form garden. In this case, the garden is defined by a series of meandering paths that lead the viewer right into and then through the plantings. Perennial flowers can also be mixed in among shrubs, planted around your mailbox, used in woodland or streamside plantings, or even planted in containers.
When it comes to deciding which perennials to plant, most of us are not very deliberate about our choices. We succumb to a luscious photo in a catalog, stumble upon an irresistible beauty at the nursery, or a neighbor sends us home with a bag full of cast-offs. If you ever do set out to make an informed and deliberate choice, here are some of the things that you should think about.
It may be hard to believe, but scientific plant names are used to avoid confusion, not create it. They are developed by taxonomists to ensure that the same plant is called the same name throughout the world, regardless of language. Scientific plant names are usually a combination of Latin and Greek.
Common names, such as "bleeding heart," are often used to refer to all the plants in a genus and are useful unless you want to ensure you are purchasing a 24-inch high, spring-blooming bleeding heart (Dicentra spectabilis) rather than the ever-blooming species known as the fringed bleeding heart, which is only 12 inches high (Dicentra eximia). To learn more about botanical names, look for a copy of Gardener's Latin by Bill Neal (Algonquin Books, 1992).
Dicentra spectabilis 'Alba': (old-fashioned white bleeding heart)
Dicentra: The first name is the genus. It is always capitalized.
spectabilis: The second name is the species. It is not capitalized.
'Alba': The third name, which appears in single quotes, is the cultivar (cultivated variety).
The appearance of a perennial garden depends as much upon the shapes of your plants and how they are arranged, as upon their colors.
Though most flowering perennials are dependable, easy-care performers, all perennial gardens require some maintenance. Here are the eight most important steps to ensure a healthy and floriferous garden:
Last updated: 10/7/19
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