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Perennials: Six Tips on Site Selection and Maintenance

By Nita Glickman 

Master Gardener℠ volunteer in Chatham County

A beautiful perennial garden depends on site selection. There are several main factors that influence site selection.

  1. Sunlight: Does the site have full sun, partial sun, or shade? How many hours of the day is the site in full sun or partial sun? Most flowering plants require full or partial sun. Only a few will do well in a heavily shaded site.
  2. Water: Perennials need about an inch of water per week in the growing season. More water may be needed in particularly hot weather. When watering apply sufficient moisture to soak the soil deeply. Water when the top 2 or 3 inches of the soil feels dry. To avoid leaf spot, water perennials from below at soil level to limit water on the leaves. If overhead watering is necessary, water early in the day so leaves dry by nightfall.
  3. Slope angle and exposure: Plants on slopes need to be watered more frequently as there will be run-off. North and east facing slopes are cooler that west and south facing slopes.
  4. Temperature: Cool season plants such as dianthus, pansies, and snapdragons do best in early spring and late fall. Heat loving plants do best if they are not in shade.
  5. Soil type: The type of soil (sand, silt, or clay) affects drainage and moisture. Most perennials prefer soil with a pH between 5.5 and 6.5. It is best to conduct a soil test when choosing a site before planting. If plants need a higher pH lime can be added to the soil. Organic matter can be added to amend the soil.
  6. Soil moisture: Most perennials do best in well-drained soil and should not be planted in a site with standing water.

To maintain perennials, consider:

  1. Watering: Most flowering perennials will need supplemental irrigation during the growing season. Watering frequency will depend upon soil type, temperature, and growth stage of the plants.
  2. Fertilizing: It is best to follow fertilizer recommendations provided by the soil test results.
  3. Mulching: A mulched garden requires less weeding and maintains soil moisture. Organic mulches also provide nutrients to the soil. Some examples of organic mulches are bark, grass clipping, leaves, pine straw, shredded hardwood, straw and wood chips.
  4. Weeding: A layer of mulch will help to control weeds. Weeds are easier to pull when the soil is moist after irrigation or rainfall.
  5. Staking: Many tall perennials such as cleome and peonies, need to be staked to protect them from wind and heavy rains.
  6. Dead heading and pruning: To maintain growth remove dead or faded flowers and seed pods.