Are perennials forever?
Well, maybe not forever, but with proper care and the suggestions this pamphlet offers, your perennials will return and multiply year after year, increasing in size, gaining in strength, and filling beds with glorious color, form, foliage, and fragrance. The perennial border has few rules, allowing both novice and veteran gardeners free range in taste and individuality. Growing from seeds requires space and time. This pamphlet focuses on perennial plants purchased at nurseries and garden centers.
Definitions
An annual is a plant that grows from seed, blooms, and then dies, all in one year. Some annuals throw off seeds that will root the following year, so they "come back," but they are not technically perennials. Some tropical perennial plants are grown as annuals in this area (they die when the cold weather comes, not because their life cycle is over.) Annuals are used to supply color for long periods; many bloom all summer. Sunflowers, impatiens, zinnias, and marigolds are examples of annuals.
A biennial is a plant that sends out a rosette the first year, blooms the second year, and then dies. Foxglove and Sweet William are examples of biennials. Biennials may reseed themselves.
A perennial is a plant that dies down to the ground each year but then regrows the following year from roots or tissues that remain in the ground. It usually has one blooming period, which can be short or long. Many perennials can be divided every few years to invigorate them. Coneflowers, goldenrod, lavender, and sedum are examples of perennials.
Why grow perennials?
Although most bloom for a shorter period than annuals, perennials come up year after year, so they are a good investment. Some provide texture as well as color, and there is a wide variety of choices when it comes to size, form, foliage color and shape, bloom size and color, and period of bloom. You can mix colors in harmonious ways and, if done properly, perennials can shade out weeds and reduce maintenance.
Even before you choose your plants, you will need answers to some fundamental questions: What are the environmental restraints? Where should you put your plants? What size and shape should they be?
Environmental considerations
The hardiness zone is an indication of average climate conditions, first and last frost dates, and regional ranges of temperatures. Chester County is in Zone 6, which has an average low winter temperature of -10 to 0° F. Keep low temperature in mind when choosing plants.
Light
Plants differ in their ability to perform well in full sun, light shade, or heavy shade. You must take these conditions into account in choosing perennials that grow well together. Some plants get "leggy" in shade, while other burn in direct sun.
Moisture and drainage
Is the bed dry or constantly wet? If the soil drains normally, it will hold water for about a week. Some plants like "wet feet," while others will rot in wet soil. There are also plants that withstand dry conditions or drought better than others. Rain sometimes is not enough to keep flower beds moist. Wet the beds thoroughly, but do not water so much the soil becomes soggy. Consistency is important.
Soil
A mixture of sand, silt, and clay (called loam) is the best soil for perennials. Perennials generally prefer soils in the pH range of 6 to 7. pH is a measure of acidity or alkalinity on a scale of 0 to 14, with 7 being neutral. Soil tests are available from the Extension office for $9 or can be purchased online at Penn State's Agricultural Analytical Services Lab website. The test measures the nitrogen, phosphorous, and potassium in soil--as well as its pH. The soil test report also provides advice on soil amendments. Acid soil can be sweetened with lime; alkalinity can be reduced with sulfur or aluminum phosphate.
Planning
Plan your garden on paper first
When sketching your ideas, consider color grouping and masses. Mass plants of the same kind to create color drifts several feet long, or clumps two to three feet around. Make sure to design plantings from the perspective of mature plants, with a foreground of short plants, a middle ground of taller perennials, and a back-ground of shrubs or tall perennials. The height of all varieties is listed in seed catalogs or on plant tags. Consider the light, soil, and moisture requirements of the plants as well as their color, form, and texture.
Choosing plants
At the nursery, examine the plant to make sure it is healthy. Look for signs of disease and insects, rather than just the number of blooms and buds, and choose a color that will be complimentary to other plants in your garden. Limit plant height to two-thirds the width of the border so that no plant is taller than four feet in a border six feet wide. When you plant, leave room for the plants to grow to maturity so they are not squeezed together.
Planting times
Generally, late summer- or fall-flowering perennials are planted in spring. Spring-flowering perennials are planted in late summer or fall. Spring planting allows the gardener to take ad-vantage of gentle rain and mild temperatures.
Mulch
Make sure to mulch your plantings to reduce weeds and conserve water. Overlap newspaper to a thickness of 1" to create your weed barrier and put the mulch on top to a depth of 2-3". Mulch materials should not contact stems of plants or trunks of trees or shrubs, as it will hold moisture against them and can cause rotting.
No matter how you do it, the single most important secret to success with perennials is to prepare the soil properly so it will drain away excess water, allow strong
