Because a perennial lives for a long time, it is important to start it in good soil. At planting time, dig the bed deeply and work in organic matter and a balanced fertilizer, such as 5-10-5.
Once a perennial is established, cultivate its soil 1 inch deep as spring growth begins, being careful not to harm its roots. Work in a tablespoon of balanced fertilizer such as 5-10-5; water well. Cultivate and feed again in 4 to 6 weeks, then apply a 2- to 3-inch mulch. Provide stakes for top-heavy plants. Water deeply in dry spells.
To keep blossoms coming, remove faded ones quickly. To make such fall bloomers as chrysanthemums bushier and more productive, pinch back the stems after each 6 inches of growth until midsummer. For giant mums and peonies, pinch off all but the end bud on each stem.
When leaves wither in autumn, cut the stalks to the ground. After the ground freezes, apply a protective mulch-8 inches of straw is good. Propagate most perennials by division; this should be done every few years, when an established plant ceases to produce good blooms.