Flowering perennials are typically herbaceous (non-woody) plants that die to the ground in fall and come up again in spring.
Technically, perennials are defined as plants that live three years or longer. In contrast, an annual is a non-woody plant that only lives for one growing season and has to be replanted each spring.
Certain low-growing perennials make effective ground covers in the landscape and a wide array of perennials are of value for cut-flowers, both fresh and dried.
Selecting perennials
Most perennials are selected on the basis of their light requirements, overall height and spread as well as bloom period.
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Equal attention should be given to foliage characteristics such as leaf color and texture, disease resistance and fall color. Many perennials are native to the Midwest; however, many are from other regions of the world and may not perform as well here so keep this mind when considering your selection.
Native plants are well adapted to local climate and undisturbed soils, but the soils and microclimates of many landscape sites have been radically altered from their natural states.
Some non-natives have been included in the lists specifically for their ability to succeed in different urban and suburban sites. A number of them have been bred or selected for their broader range of color, form and texture. Keep in mind that some of the horticultural characteristics that make plants successful in the landscape may also make them aggressive. This is true for both native and non-native plants.
This does not necessarily make such plants bad, and it is the responsibility of each of us to match plant selections to site conditions.
Soil preparation
Good soil preparation is the key to success with perennials since they will occupy their spot in the garden for several years.
Most perennials prefer a well-drained soil that is high in organic matter. With heavy soils that may drain poorly, you may consider raising the area to improve drainage.
For heavy or light soils, incorporating garden compost, well-rotted manure or peat into the top 8-12 inches will increase the organic matter and aid in drainage and soil aeration.
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Mulching
Organic mulches such as wood chips, shredded bark or leaves are beneficial in many ways.
They help provide a cool, moist soil that perennials prefer, help to reduce weeds, allow perennials to spread and help in over-wintering by reducing frost penetration into the soil.
For winter, a 4-inch to 6-inch mulch of leaves, marsh hay or straw will provide protection for shallow-rooted perennials like mums, shasta daisies, delphiniums, etc. Rock mulches restrict the spreading of perennials.
Dividing perennials
Many perennials benefit from being divided periodically. If permitted to go undivided, they become crowded, lost their vigor and become vulnerable to diseases.
Iris, daylilies and lilies are some of the perennials that benefit from being divided about every three years. Other perennials may never need dividing.
Consult your local garden center if you are unsure as to what varieties need dividing.
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Designing a perennial bed
Designing a perennial bed can be an enjoyable experience.
For the beginner, it may seem a bit overwhelming, but keep in mind that if you are not happy with the initial planting scheme, it can always be changed.
Obtaining, for the first time, perennials that will give you a good mix of seasonal bloom, color and the proper heights, can be difficult even for an experienced gardener.
It is usually best to start with a plan. Take time to sketch out a drawing of what you'd like to accomplish. Then take this to your local garden center and ask for their advice on specific plant selections.
