Perennials

Planting Perennials

Because your perennials will grow in the same place for many years, it is particularly important to do a good job of preparing the soil. Once planted, you cannot fix the soil as easily.

If you are beginning a brand new garden, work in two to four inches of organic matter (such as Harvest Supreme Compost or well-rotted compost) at least 6″ to 8″ deep, to improve the soil and add beneficial microbes. This is particularly important to improve drainage in heavy clay soils, or to improve water-holding capacity in sandy soils. Apply about 2 pounds of low-nitrogen fertilizer such as Dr. Earth Starter Fertilizer, 5-10-5 Flower Fertilizer or 5-10-10 Vegetable Fertilizer, per 100 square feet and work it into the top 4 to 6 inches of soil.

If you are planting a new perennial into an existing garden, dig a hole two to three times wider than its container. Mix 25% Harvest Supreme Compost into the soil removed from the hole, and add Dr. Earth Root Starter Fertilizer into the soil mix.

Carefully remove the perennial from its container by holding one hand over the top
of the pot and turn the container upside down. Gently tap the bottom of the pot to loosen the root zone from the container and gently pull the pot away. If the container does not easily come off, it may be necessary to squeeze the container until the plant comes out of the pot. Place the plant in the hole so the top of root ball is at the same level as the top of the hole. If necessary, place a little soil back in the bottom of the planting hole to make sure the plant is not too deep. Many perennials do not tolerate being planted too deeply and may not grow very well, or they may even die. Conversely, perennials planted too high may not grow properly and are more susceptible to drying out.

Once the plants are at the proper height, fill in the planting hole with soil, gently packing the soil around the roots. After planting, it is important to water them well. For the first couple of weeks, it is important to keep the soil moist, but not soaking wet. Keep in mind that many new plantings do not perform well because they are either over-or-under watered. After four to six weeks, most perennials can tolerate less water.

Care and Maintenance of Perennials

Blooming perennials in the garden are glorious – until the blooms begin to fade and you are not sure what to do with the plant. It’s misleading to think that once you plant a perennial flower you are done with it. To have great looking perennials, there is a good bit of maintenance involved.

Watering – While some perennials are drought-tolerant, many need plenty of water. If the soil dries out, it’s important to thoroughly soak the soil when you water, not just wet the surface. It’s also important to keep the foliage and flowers as dry as possible
to prevent disease. Soaker hoses and drip irrigation do this well. If you use sprinklers, run them in the morning so that the plants dry quickly in the sun. Watering individual plants by hand requires patience; to apply enough water to thoroughly soak the soil.

Fertilizing – Most perennials do not require heavy fertilization. Fertilize with a low-nitrogen fertilizer (5-10-5 or 6-10-4) in the early spring, and again two more times at 6-week intervals. Keep fertilizer off foliage to prevent burning. You can use Osmocote or Dr Earth Organic Fertilizer to reduce possible burning. Fertilizing too much can lead to soft, leggy growth making the plants floppy. You don’t want to encourage a lot of growth near the end of the season either. The new shoots will get nipped in the crisp autumn air.

Staking – Some taller perennials tend to fall over, especially when they are heavy with flowers. To keep them upright, you can plant them so other plants help support them, or plant them next to a house or fence. Another alternative is to put stakes around the plants while they are small and, as they grow, fasten the plants to the stake. There are many decorative supports available to make your garden look perfect; link stakes, plant grids, cages, obelisks and even small trellises.

Pinching – Some perennials respond well to pinching — removing the growing tips by pinching off the small, developing leaves at the tips of the stems. This makes the plant shorter and bushier. Chrysanthemums respond especially well to pinching them back.

Thinning – This helps increase air circulation and prevent diseases, especially in those prone to mildew and leaf spots. When the plants are about 25% to 50% of their full height, cut half of the stems to ground level. This can also increase the stem strength and the flower size.

Pruning after Flowering – Some early bloomers, such as creeping phlox, candytuft, and rockcress, may bloom again if sheared back immediately after their first bloom. Try this also with midseason bloomers; yarrow, ladies’ mantle, Shasta daisy, delphinium, cranesbill (geranium), catmint, salvia, and veronica. Depending on species, most late-summer and fall bloomers do better with less aggressive pruning.

Dis-budding – With some perennials, especially those used for cut flowers such as peonies and chrysanthemums, you can encourage fewer but larger blooms by removing the smaller lateral flower buds. This forces plants to put more energy into the terminal bud. Or, you can remove the terminal bud and encourage more of the smaller lateral flowers.

Dead-heading – Remove spent flowers after the blossoms start to fade. This keeps the plants from wasting energy on seed production, and keeps them looking neat. In some species, dead-heading can encourage another flush of flowering. It also prevents perennials that reseed aggressively from spreading where you don’t want them. As a general rule, remove the faded blossom and stem down as far as the next healthy blossom, or set of leaves.

If you are trying to attract birds to your garden, don’t deadhead species with seeds favored by birds. Be careful dead-heading biennials. Don’t remove the flowers before the seeds mature and have a chance to drop, or they may not come back next year.

Fall Care – Perennials should not be cut down as winter approaches. Instead let them die down naturally to avoid damaging the plant. However, you may want to prune them lightly towards the end of fall to remove any diseased, damaged, or dying foliage.

Many perennials go completely dormant and die back to the ground each year. After they are dormant, you can cut these perennials perennials back to about 3 inches from the ground. Any closer may damage crowns. Remove debris from the garden to help prevent diseases.

Other perennials, such as ornamental grasses, upright sedums, and ferns, are often trimmed in the spring allowing the foliage to provide some interest to the winter landscape. In addition to adding winter interest, some perennials overwinter better if left uncut. The uncut stems and leaves add an extra layer of insulation.

Winter-Mulching – Many perennials benefit from a protective layer of mulch to help them overwinter. Wait until after several killing frosts and the soil is cold. If you apply mulch too early, it will hold warmth in the soil and some plants may break dormancy
and start growing again. This new growth will be killed by cold weather. Spreading mulch too thickly over the crowns can trap too much moisture, and encourage them to rot. In the spring, be sure to remove mulch gradually when plants begin growing.

Dividing – With age, many perennials won’t grow as vigorously as they did when you first planted them; and they flower less. The center of the clump may appear dead, with little or no new growth. When this happens, it’s a good sign that the plant is ready to be divided. The best time and method of dividing perennials varies with species. In most cases, you divide plants when they are dormant, either early in the season before they break dormancy, or in the fall so that the roots can settle in before the ground freezes.

In most instances, dig out the entire plant, wash the soil off the roots, and cut or pull them apart into several pieces. Sometimes this can be quite difficult, especially with older plants and with ornamental grasses. Replant the newer, more vigorous roots and
discard the older or diseased parts.

Perennial Blooming Guide

Flower beds are the exciting part of outdoor gardening. They can turn bland and boring spots into enticing and alive spaces. They can be incorporated into any existing landscape design. People grow perennial flowers because they are such easy-care, dependable performers, and because they offer a wide selection of size, leaf texture, flower types, colors, and blooming seasons for your flower gardens. Many of the first flowers of the season are perennials – aubretia, basket-of-gold, creeping phlox. Perennials also give us the last colors of autumn – toad lilies, asters, and chrysanthemums.

Unfortunately, most perennials have a relatively short bloom period; 3 to 6 weeks every year. Selecting perennials that bloom at different seasons will give you color throughout the year. You can also add annuals, bulbs, and shrubs to complete the effect. With so many different species of perennial flowers to choose from, few people ever become completely familiar with all their options.

Good for Cut Flowers

Good for Shady Areas

Good for Hot, Dry Areas

Good for Rock Gardens