Tips for Growing Perennials

Few things delight gardeners more than awaiting the yearly return of their perennials. Perennials are distinct from annuals in that they return year after year, eliminating the need to buy new flowers every spring.

Perennial Flowers Image Gallery

Unlike annuals, perennials generally bloom only one or, at the most, two seasons per year. There are spring bloomers, summer bloomers, or fall bloomers. When they're not in flower, perennials are enjoyed for their foliage, which is at least as important a consideration as the blooms.

Perennial shapes and sizes also add to the mix. There are tall perennials like plume poppy that tower over your head and creeping perennials like moss phlox that carpet the ground.

Perennials may grow and expand each year, eventually filling more space than you might expect. To keep perennials under control and growing well, many need division (digging up the root clump, dividing it into sections, and replanting the best sections in freshened soil). This can provide a harvest of new plants for use elsewhere in the garden.

Many perennials fall into the following shape categories. But you should expect variations as the seasons progress. Perennials usually stretch up to flower and then fade back to their foliage after the bloom is through.

Mats: Perennials such as lamium, bugleweed, and plumbago form low carpets suitable for ground covers or the front of the border.

Mounds: Nicely rounded perennials such as coreopsis and hostas provide a soft look.

Flower sprays with low foliage: Perennials such as yarrow, sea thrift, and coral bells bear taller flowers over neat low foliage. Height is dramatically reduced when the old flower stems are removed.

Vase shapes: When in bloom, plants such as garden phlox and Shasta daisies grow in an inverted triangular shape.

Spikes: Plants such as salvias, lupines, gayfeathers, and delphiniums have slim, vertical flowering stems that contrast well with more horizontal forms.

In the next section, we'll talk about the factors you should consider when selecting perennials for your garden.Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.

Contents

Choosing Perennials
Ideas for Displaying Perennials
Planting Perennials
Caring for Perennials
Perennials and Other Plants

Choosing Perennials

Perennials represent a truly diverse group of plants. Choosing which to grow in your garden shouldn't be overwhelming. Use the following tips to help find the best perennials for your garden.

Choose healthy plants. For the inexperienced buyer, this may be easier said than done in the spring. Potted perennials may be showing only a little foliage, not providing much information about the health of the plant.

Look at the plant crown, the place where the shoots emerge from the soil. The emerging stems and leaves should be nicely green and showing no sign of wilting or rotting. Study the foliage and soil surface for signs of pests, which might be feeding on the crown, beneath the leaves, or fluttering up when you move the pot. If you find extensive evidence of pests, buy your plants elsewhere. Ask a sales clerk if you can look at the plant roots. Turn the pot over and slip the root ball out. The roots should fill the pot, but not be crammed into it, and they should be healthy and firm.

Keep your expectations for plant life realistic. Although perennials like daylilies and hostas can live for decades, some perennials live only a few years. Perennials with short-but-sweet lives include columbine, blanketflower, and some chrysanthemums. Propagate new plants using division, cuttings, or seed to have replacements ready when needed.

Avoid wildflowers collected in the wild. Some people snatch wildflowers from native areas instead of propagating them in a nursery. This depletes the natural environment and can result in inferior plants not prepared for garden life. Buy from a reputable garden center or nursery. Ask where they got the wildflowers and whether they were nursery propagated.

Be suspicious if you see pots with several small plants packed irregularly, which may have been taken from the wild. Flowers that are poorly rooted may have been recently dug and stuck in a pot. If you see wildflowers sold for less than a comparable perennial, it's a sign that they may have been harvested in the wild.

Choose single-flowered peonies over the double-flowered types. A single-flowered plant has a solitary row of petals (or several rows, in the case of peonies) around the perimeter of each blossom. Double-flowered plants have many rows of petals, which form a full, fluffy-looking flower. The big advantage of single-flowered peonies is weight. With fewer petals, the flowers stay lighter and are less likely to fall over when in full bloom. This means they don't need staking. The flowers are also less likely to trap moisture and, consequently, tend to suffer from fewer diseases.

Choose disease-resistant cultivars of garden phlox and bee balm. Both perennials can be troubled with mildew diseases, which cover the plants with ugly white fuzz. Fortunately, developing disease-resistant cultivars has become a priority in the nursery industry. Check perennial catalogues to identify the best new cultivars for your climate.

Use salt-tolerant perennials in cold-climate roadside plantings. Roads heavily salted during winter snowstorms often leave salt residue in the soil. Perennials such as sea thrifts, bearberry, and rugosa roses thrive in soils that are salty enough to kill other plants.

Use plants adapted to dry conditions in drought-prone climates. Perennials such as butterfly weed have deep or moisture-storing roots that allow them to weather dry conditions. Other drought-survival specialists have leaves that are modified to reduce moisture loss. Silver leaves reflect hot sunlight, and needle-shaped leaves have less surface area for moisture loss. Moisture is stored inside succulent leaves, and moisture loss for furry leaves is slowed by their furry coating.

In our next section, we'll share ideas for displaying perennials in your garden.Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.

Ideas for Displaying Perennials

With so many varieties of perennials to choose from, gardeners have almost limitless options for displaying these lovely plants. The following creative gardening ideas will help you get started.

Arrange the perennial garden so that you can see and enjoy every plant -- regardless of how small it is. Place the tallest plants in the rear of a border that is viewed exclusively from the front. In an island bed viewed from all sides, place tall plants in the middle.

Work medium-height plants into the middle of a border or island bed, filling out the garden in front of the taller plants. Set small plants up front, where they won't be hidden by taller leaves or flowers. The neat progression of short to tall gives a garden a sense of order and tidiness many people appreciate. Don't be too rigid, however. You can work some medium-size varieties into the plants up front to add interest. Bring a few tall plants forward to break up any tendency to make height organization rigid.

Combine several different perennial forms to keep the garden from being monotonous. Diversity provides spice to perennial gardening.

Convert your front yard to a cottage garden. Tending flowers is much more fun than mowing grass!

Plant shade-loving perennials on the shady north side of shrubs if you don't have trees. Perennials such as anemones, astilbes, hostas, Lenten roses, and violets can look lovely against a backdrop of evergreen shrubs. Flowering deciduous shrubs such as viburnums or hydrangeas can be even more beautiful.

Interplant perennials with reseeding annuals for a lush look that changes every year.

Plant perennials instead of grass in the boulevard strip. The boulevard strip is the very public space located between the sidewalk and the road. It can be hot, dry, and heavily trod upon, which makes it difficult to keep grass looking healthy and nice. Instead of fighting a constant battle with turf, use a different tactic. Plant the boulevard strip with low but bushy perennials that people won't walk on. Choose heat- and drought-tolerant perennials such as coreopsis, Silver Mound artemisia, and sea thrift. Now the problem area can become a pretty garden.

Start a shade garden under trees by adding 4 inches of compost over the tree roots before planting. Rich, moist compost provides a fast start for newly planted perennials. This is important -- the flowers need to be growing strongly before tree roots move in and capitalize on their growing space. Compost also helps keep the garden moist in summer, when the trees and perennials may compete for water. Just be careful when planting not to damage the tree roots.

In our next section, we'll talk about the process of planting perennials.

Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.

Playing with Height Variations

Plant some medium-height early bloomers such as columbines toward the front of the garden. They will flower before the other perennials are stirring and can be cut back after flowering so that only compact leaves remain.
Swing an arc of medium-height plants up toward the front of the border, making a gentle curve that softens height restrictions but doesn't extend so far into the front of the border that it becomes restrictive.
Loop a small drift of shorter edging plants back into the medium-height flower section to ease the dividing line between the two.
Use plants with airy sprays of small flowers at the front of the garden. Perennials like baby's breath and coral bells have see-through veils of blossoms that don't obscure what's behind them. This can make the garden sparkle.

Planting Perennials

Start your garden off right by taking care to plant your perennials properly. The following tips will help you get started.

Soak bare-root perennials in a bucket of water for an hour before planting. Bare roots have been out of their element (moist soil) while handled and shipped. Letting them soak up a little extra moisture can refresh moisture levels so the roots can grow vigorously in the weeks ahead.

Shake the potting mix off the roots of potted perennials and plant them like bare-root perennials. Larger perennials sold in 1- or 2-quart-size containers are perfect candidates for this. The reason for doing this is that peat potting mixes can complicate plant establishment in the soil. The roots of perennials grown in peat-based mixes can have difficulty growing out of the peat and into the native soil. In addition, peat can quickly become parched in drying soils, causing root damage. Getting the peat out eliminates both of these problems and can help new perennials get established faster than you ever thought possible

Space large, slow-growing perennials properly at the start. Big hostas, goat's beard, gas plants, and roses, for example, can be hard to move once they are established. Ask at the nursery or check in a garden encyclopedia for information on how big the plant will get. Then be sure to allow enough space for the plant to reach its mature limits without overcrowding.

Plant tall perennials together so they can support each other and need no staking. Combinations such as boltonia and asters, yarrow and butterfly weed, or daisies and irises can result in pretty blends of flowers and foliage.

Make an artificial bog for plants that need constantly wet soil. Then you will be able to grow swamp irises, variegated cattails, ligularias, and other water-loving plants. Begin by deciding where you want the bog garden to be located. They are natural companions for fountains, water gardens, bridges, or streams. Dig out a deep trench or swale for the bog garden, then line the hole with plastic. Set a perforated hose in the bottom, with an end emerging from one side to connect with your household hose. Fill the hole with rich soil and plant bog natives. You can irrigate through the submerged hose as needed to keep the garden constantly moist.

In our next section, we'll show you how to care for your perennials.

Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.

Planting Bare-Root Perennials

When planting potted perennials, the shape of the pot is a good match for the hole you dig. But bare-root perennials tend to have octopuslike roots that need different treatment.

Dig a wide, shallow hole in well-prepared soil.
Form a cone of soil in the center of the hole. Make the cone high enough to hold the crown (where the shoots emerge from the roots) at the soil surface.
Spread the roots around the perimeter of the cone so that each has its own space. The hole should be deep enough to accommodate the entire root length without a lot of cramming, twisting, and turning.
Fill in around the roots with soil, and keep it moist.

Caring for Perennials

Caring for your perennials as they grow helps will help ensure their blooming return the next year. These tips will help you do just that.

Avoid overfertilizing sun-loving prairie plants like coneflowers, yarrow, and coreopsis. Excess fertilizer stimulates taller growth, making these plants more likely to weaken and flop over.

Pinching is one of the handiest things you can do in the garden. Removing the stem tip, with a pinch of your fingernails or with pruning shears, makes plants more compact and bushy.

Pinching is particularly helpful for mums and asters. Flowering plants purchased in a pot have been specially treated to make the plants bushy and full. If left untouched the following year, they will grow fewer, taller, scraggly stems that are more likely to need staking for support.

When pinching, scheduling is important. You want to start early enough to make an impact. And you need to stop by July 1 so flower buds can develop before heavy cold strikes. Start with this pinching schedule but feel free to modify it as you gain experience: Pinch shoot tips when the stems are 4 to 6 inches high. Pinch again three weeks later. Pinch a final time in late June.

Shear reblooming perennials such as catmint and moonglow coreopsis to promote a second flush of flowers. Getting rid of the old flowers and seed pods encourages new growth, new buds, and new flowers. This is a great reward for a small amount of effort.

Renew a declining clump of perennials by division. As many perennials grow, new shoots emerge at the perimeter of the clump, which keeps spreading outwards. The center becomes increasingly older -- sometimes woody, sometimes completely barren.

The solution is division. In spring, late summer, or fall, dig up the entire clump. Cut out the old heart, refresh the soil with organic matter, and replant healthy young pieces. You may have enough good divisions left to share with friends.

Support full, floppy perennials with pruned twigs. This is an old British trick called pea staking. It helps perennials stay upright and look natural without glaring metallic stakes or forced shapes that result from corseting with twine. Even better, pea staking costs nothing but a little time.

When the perennials begin to arise in spring, set the ends of sturdy branched twigs around the plant. The twigs should be about as long as the height of the perennial. As the stems grow, they will fill out to hide the twigs. You can cut off any errant woody stems that remain in sight after the perennial reaches full height.

In our final section, we'll talk about how perennials can interact with other plants in your garden.Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.

Perennials and Other Plants

Perennials don't have to spend time in the garden alone. Pair them with other plants for lovely, suprising results.

Plan ahead to cover the gaps left by perennials that go dormant in summer. Two of the most common now-you-see-them-now-you-don't perennials are sun-loving Oriental poppies and shade-loving old-fashioned bleeding hearts. When done blooming, both plants slough off their old foliage and hibernate underground. This creates vacant places in the garden. But with a little planning, you can easily work around them.

Organize gardens so that neighboring plants can fill in and cover for the missing greenery. In shade, the ample foliage of hostas and ferns can move into voids left when old-fashioned bleeding hearts go dormant. In sun, hardy geraniums, frothy baby's breath flowers, and spreaders like dragon's blood sedum can fill in for Oriental poppies.

Plant Oriental poppies or bleeding hearts individually instead of in large clumps or drifts, which leave larger holes.

Set a potted plant, such as a houseplant spending the summer outdoors, temporarily in the opening.

Avoid dense tree roots by planting a shade garden around the outside of the tree canopy rather than directly underneath. Many tree roots cluster under the branch canopy, and active feeding goes on near the drip line, the place where rainwater drips off the leafy branch tips. Gardening beyond the shadow of the limbs reduces root competition, and the plants will get more light.

Lessen the impact of wind by planting tall perennials and ornamental grasses to shelter a garden full of more delicate plants. Sturdy-stemmed perennials, which are not likely to topple over with the first big gust, grow large enough to curb the wind faster than most shrubs and trees. Some perennials to try are maiden grasses, pampas grass, boltonia, goat's beard, and large hostas.

This tip also works on a smaller scale. You can plant smaller, delicate flowers beside sturdy medium-sized plants like purple coneflowers and irises for wind protection.

Use a string trimmer to cut back ornamental grasses in spring. The golden leaves and seed plumes are a great winter attraction. But in spring, the old growth must be removed before the new shoots begin to sprout. The string trimmer quickly cuts through grass stems. Rake them up and toss them on the compost pile -- job finished!

Make planters out of old tree stumps that are next to your house, in a mixed border, amid a grove of shade trees, or in a woodland edge. In nature, old stumps slowly begin to decay and provide fertile places for ferns and other interesting small plants to grow. You could plant flora native to your area or fill the opening with brightly colored annual flowers and vines.

Follow nature's lead and you will get several benefits: You won't have to pay to have the stump ground out; you can grow plants that need good drainage or special soil mixes right in the trunk; and you create an interesting, sculpturelike structure.

Chip some wood out of the top of the stump to create rooting space. Fill with a soil mix that's appropriate for the plants you intend to grow. After planting, water as necessary to keep the soil moist.

Want more gardening tips? Try:

Gardening Tips: Learn great helpful hints for all of your gardening needs.
Annuals: Plant these beauties in your garden.
Perennials: Choose great plants that will return year after year.
Gardening: Discover how to garden.