How to Choose and Plant Perennials

Perennials can add beauty and utility to your garden year after year. And with a wide range of colors, textures, sizes, and shapes to choose from, it’s no wonder perennials are favorites among gardeners.

Learn when to plant perennials, how to choose them based on your climate and garden plot, which plants to consider, and how to care for your perennials year-round.  

The best time to plant perennials

Fall is an ideal time to plant most perennials, and they’ll reward you with delightful foliage and blooms in the spring and summer.

Fall’s cooler temperatures mean that plants will be less stressed and will need less water than if you planted them in the summer heat. In addition, planting well ahead of winter—at least six weeks before a hard freeze—gives plants a chance to develop strong, healthy root systems.

Choosing perennials for your garden’s sun exposure

Before selecting plants, consider the location of your gardening space. Is it in full sun? Partial shade? Full shade? This will help you determine which perennials will grow best in your garden.

Perennials that like to soak up the sun, such as blanket flowers, coneflowers, salvia, sedums, daylilies, coreopsis, and yarrow, simply won’t be happy in a shady spot. Likewise, shade or partial shade lovers such as heucheras, hostas, and ferns won’t reach their foliage potential in full sun.

Popular perennial plants for different sun and shade conditions

Once you’ve determined how much sunlight your garden gets, consider planting these perennials:

Perennial shade lovers: 

Wild ginger (Asarum) grows low to the ground, and while it has small blooms, it’s often favored for its heart-shaped foliage.

Cast-iron plant (Aspidistra elatior) is a tough foliage plant with long, arching leaf blades that can extend up to 2 feet long and up to 4 inches wide.

Lily of the valley (Convallaria majalis) is a charming plant that grows 6 to 8 inches high with arching stems of tiny white bells in the spring. The broad foliage lasts through the growing season.

Ferns add texture to gardens with lace-shaped, arching fronds. Most grow between 1 and 3 feet tall.

Cardinal flower (Lobelia cardinalis) sends up 2-feet slender spikes filled with vibrant red flowers, adding a lovely accent to foliage plants in a shaded garden.

Perennials that thrive in partial shade:

Green-and-gold (Chrysogonum virginianum) is a low-growing plant with bright green foliage that is accented with star-shaped, bright yellow blooms from spring to fall.

Solomon’s seal (Polygonatum species) sends up arching stems with oval leaves on either side. Clusters of small, bell-shaped white blossoms hang beneath the stems through the spring and early summer.

Wild cranesbill (Geranium maculatum) grows up to 2 feet tall with deep green, lobed leaves that are accented with pale purple, five-petaled flowers in late spring or early summer.

Lenten roses (Helleborus x hybridus) delight gardeners in late winter and early spring with flowers that are white, various shades of pink, pale green, or purple, depending on the variety. The plant, with its evergreen foliage, grows to about 1 foot and is attractive year-round.

Coral bells (Heuchera species and hybrids) grow in clumps or mounds. The plant sends up slender stems of tiny blooms, though it’s best known for its wide range of leaf colors, depending on the species.

Perennials who love the sun:

Agapanthus lends a strong, structural accent to the garden with its tall bare stems that grow up to 5 feet tall, depending on the species. Round clusters of funnel-shaped lavender flowers burst from the end of the stems.

Baptisia, sometimes called false indigo, grows between 1 and 3 feet tall. Impressive flower spikes filled with blue, yellow, or white pea-shaped blooms extend up to 2 feet and bloom for several weeks, depending on the species and climate.

Salvia is in the sage family and its variety of species gives you many bloom colors to choose from. Salvias can grow anywhere from 1 to 7 feet tall, depending on the type you choose.

Daylily (Hemerocallis species and hybrids) forms clumps of arching, sword-shaped leaves that accent the lily-shaped flowers. Available in a wide range of colors, daylily species and hybrids are impressive in mass plantings.

Black-eyed Susans (Rudbeckia species) grow up to 3 feet tall with large, daisy-like yellow flowers and dark brown centers. This common favorite can mix well in borders or create bold impact when planted in a group.

For more ideas, visit the Clemson Cooperative Extension, which provides an extensive list of perennial plants for each of these conditions, and others.

Know Your planting zone

When purchasing any kind of plant, it helps to know the USDA Plant Hardiness Zone for your region. Visit the USDA website and find your hardiness zone by typing in your ZIP code. Most plant tags list information on which zones the plant will grow best in.

Prep your soil for perennial planting

The soil condition of your gardening space is an important factor in growing happy perennials. Good soil yields prettier, healthier plants. Before buying plants, take the time to spade up your soil and, if needed, add amendments such as manure, compost, decomposed leaves, or topsoil. Use a shovel or a rototiller to work or till the soil to a depth of 10 to 18 inches. A well-worked soil site improves aeration and drainage, which are important. Avoid working the soil when it is wet.

Soil tests can provide important information about the soil pH and nutrient content. Departments of Agriculture in many states conduct soil testing for a nominal fee, and soil test kits are available through many Cooperative Extension offices. The kits provide guidelines on how to collect the soil and where to send it for analysis. The report you receive back recommends fertilizer to use for the plants you are growing and when to apply it.

In the absence of a soil test, Clemson Cooperative Extension recommends using a complete fertilizer such as 10-10-10 at the rate of 1 pound per square foot of bed area, or applying complete organic fertilizer following label directions.

How to select perennial plants for your garden

Knowing how much sunlight your garden gets and what plant hardiness zone you’re in, you’re ready to shop for perennial plants. With thousands of plants to choose from, it’s a good idea to ask yourself some key questions to narrow down your options further.

• What do you want to accomplish in your garden?
• Do you want a cutting garden?
• Do you want to create an island bed in your lawn that will add visual interest to your landscape?
• Do you want a perennial bed or border that will add color and impact?
• Do you want to fill in a shady area with foliage plants?
• Do you want a sweep of ornamental grasses?
• Are you looking for low-growing edging plants?
• Do you want plants that work best in a rock garden?

With a better sense of your garden vision, here some tips to keep in mind:

Plant placement based on size:

When planting in beds or borders, place the tallest plants in the back. When planting an island bed that can be viewed from all sides, place the tallest plants in the middle. Place the shorter plants in the front of the bed.

Planting for visual impact:

While a variety of colors, shapes, and textures is quite pleasing, mass planting of one type of plant or one color is too. So consider grouping in clusters.

Mixing foliage and blooms:

Foliage plants are beautiful mixed with plants that bloom, adding a place for the eyes to rest while helping colorful blooms stand out. In addition, perennial blooms aren’t the only plants that provide an entire color palette to choose from. Foliage plants also come in a wide range of hues, such as yellow, caramel, bronze, pink, gray, and silver, as well as and many, many shades of green.

Preparing perennials for colder months

At the end of the growing season, after the foliage of perennials have died, some gardeners remove the leaves, seed heads, dried foliage, and stems. Others leave them for wild birds to enjoy. When the soil temperature has dropped after a frost or two, apply mulch around the perennials to protect them during the winter. Avoid piling the mulch heavily over the crowns of the plant. Remove the mulch in early spring.

Perennial payoff

Perennials are an investment in your landscape. The payoff is the reward of a beautiful garden you can enjoy year after year.