Perennials are plants that rejuvenate themselves every year.

Most perennials have one blooming period every year.

Annuals, in contrast, grow for one season, bloom, and then die.

Biennials send out a rosette one year, bloom the next year, and then die.

There are many reasons to plant a perennial garden. Perennials often require less maintenance than annuals. Also, unlike annuals, perennials are present in the winter and can be attractive over the course of the entire year.

A perennial garden can serve to permanently soften harsh corners on buildings.

Gardens also ease mowing problems along fences or walls. Planting a perennial garden will add value and beauty to your property.

One of the unique joys of growing perennials is seeing the plants return to life year after year. Every summer more plants will grow. These plants can be relocated to new gardens after the parent plant is divided.

A good perennial garden is created to reflect the environmental conditions in which it is found.

An important first step to planting perennials is to have a soil test completed to determine which plants would thrive in your garden’s natural climate, or what soil additives you will need to add to create the optimal soil.

Also, keep in mind how much sunlight the garden gets, the hardiness zone and the amount of moisture in the area.

Once you have determined what plants will be compatible with your garden’s environment, you should consider other design principles such as color, size and shape.

It is a good idea to use clumps of the same type of flower to create a bigger visual impact. If desired, repeat the same type of plant on both sides of the garden to add symmetry.

Try to plant flowers whose colors and shapes will complement each other. For example, a plant with yellow foliage will make blue flowers pop. Similarly, spike shaped blooms will appear striking when paired with flat shaped blooms.

The first maintenance consideration is water. Plants sometimes require more water than they get from rainfall alone.

When nutrient levels are low, plants will discolor, stop blooming and become more susceptible to disease. To avert these situations, add nutrients from natural sources such as compost or manure or use a commercial fertilizer.

Weeds can be a pesky problem in perennial gardens. To keep them under control, cover the bare soil with some type of mulch and plant groundcovers that can compete with the weeds.

Most perennials need to be divided every two to three years. Many gardeners neglect to divide their plants which results in crowding and dieback in the center of the plant. Divide plants in the spring or fall when the plant is not blooming, and the weather is not too hot.

Another common pitfall involves the design stage of perennial gardening. Although it is difficult to see how a plant will look at maturity based on the size of the plant you purchase from the nursery, it is necessary to research the mature size of the plant to be sure to leave enough space around each plant. If plants are too crowded, they will perform poorly.

Gardening events

May 11, 12: The Seed Farm’s Annual Spring Plant Sale, 5854 Vera Cruz Road, Emmaus, 9 a.m. - 3 p.m. May 11; 11 a.m. - 2 p.m. May 12. Penn State Master Gardeners will be available to answer gardening questions.

May 14, Pollinator Friendly Ordinances: 7 p.m., Lower Macungie Township Community Center, 3450 Brookside Road, Macungie. Speaker: Pollinator Steward Heather Andrews. Admission is free.

“Growing Green” is contributed by Diane Dorn, Lehigh County Extension Office Staff, and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.