Perennials are plants that return to beautify your garden year after year. Although the plants may look dead in winter, the roots are alive and regrow with the arrival of warmer weather. With proper planning, the color lasts throughout the growing season, as some perennials put on a show in early spring, while others wait until mid-summer or autumn. Proper care allows many perennials to live for decades.
Although water requirements vary depending on the type of perennial, most benefit from plenty of water during dry periods. Soak the soil deeply, but avoid wetting the foliage more than necessary. If you need to use a sprinkler, water early in the day so the moisture on the foliage has time to evaporate before evening. Most perennials aren’t heavy feeders, but benefit from a feeding every six weeks beginning in spring. Use a fertilizer with a ratio similar or equal to 5-10-5 applied at a rate of no more than 5 pounds per 100 square feet of planting area. Keep fertilizer off the foliage, and water immediately after applying fertilizer.
Most blooming perennials benefit from pinching-off of the small leaves growing at the tips of stems. Pinching plants in spring creates full, bushy plants. Wilted flowers are deadheaded throughout the season to prevent the plant from going to seed too early, as a plant that goes to seed will stop blooming. To deadhead your plants, pinch off the spent bloom. Include the stem down to the next bud or leaf. Leave a few blooms on the plants in late summer if you want the plant to reseed, or if you plan to harvest the seeds.
Perennials are cut back either after the plant dies down in autumn or before new growth appears in early spring. The timing is mostly a matter of personal preference. Gardeners that are choosy about a tidy garden often cut plants back in autumn. Cutting back in autumn is beneficial, as removing the foliage provides air circulation and drier soil that prevents pests and disease. Some gardeners prefer to leave the plants until spring, as the dead foliage provides food and shelter for song birds.
Spread a 3- to 4-inch layer of mulch around plants in late autumn, but not until the ground is cold and you’ve experienced several frosts. Mulching too early can warm the soil and trick the perennials into growing, putting the plants at risk of freezing during winter weather. Remove the mulch after the weather warms up in spring.
Divide perennials when the center of the plant begins to die back, or if the plant seems to lose vigor. Most plants benefit from division every two to four years. To divide perennials, dig the entire clump, then use your hands, a knife or a sharp shovel to separate the clump into smaller sections. Plant the sections and discard any dead, woody or unproductive sections.