How to Maintain Perennials

Once planted perennials have established, regular maintenance is required to ensure continual plant and flower health and growth.


Materials Required:

  • Mulch
  • Gloves
  • Pruning shears/secateurs
  • Trowel/hand tools
  • Hoe
  • Shovel
  • Rake
  • Watering can/hose
  • Stakes/peony rings/cages


  1. Deadheading – the removal of spent flowers.

    1. Ensure that your pruning shears/secateurs are clean.
    2. Cut back the stem of a spent flower to an intersecting stem or leaf.

This procedure encourages plants to rebloom and prevents plant rots and diseases that attack decaying blooms. Deadheading also inhibits the production of seeds, permitting additional energy for blooms and growth.

  1. Pinching back – the removal of the top portion of the plant.

    1. For each stem, find the spot just above the top leaf or bud (approximately 1-2 inches from the top).
    2. Using gloved fingers, pinch off the top portion. 

This procedure encourages bushy, compact growth and is ideal for plants that are “leggy” (stretched growth and weak stems). Pinching can sometimes avoid the need for staking.

  1. Shearing – the removal of the stems after the plant has flowered. 

    1. Ensure that your pruning shears/secateurs are clean.
    2. Cut off approximately ⅓ - ½ of the top portion of the plant’s stems.

This procedure improves plant appearance and encourages rebranching and tidier growth.

  1. Thinning – the removal of entire stems.

    1. Ensure that your pruning shears/secateurs are clean.
    2. Remove approximately ⅓ of the plant’s stems.

This procedure increases air circulation and encourages flower production. Some mature perennials grow numerous stems that crowd and shade each other. This can prevent the plant from reaching its maximum bloom potential and make it vulnerable to diseases and insect attacks. Plants which are prone to powdery mildew – Garden Phlox and Bee Balm, for example – benefit greatly from thinning. 



  • Water requirements are specific to plant type, but most plants require approximately 2.5 cm (1 inch) of water every week.
  • For a newly planted perennial, water occasionally, but thoroughly (as opposed to frequent, shallow watering),



  • Plants should be fertilized in the spring as they begin to grow, after transplanting or dividing them, and after grooming. Do not fertilize after August 1st so as to allow the plants to prepare for winter dormancy.
  • Water soluble fertilizers provide plants with nutrients quickly, while granular fertilizers feed plants nutrients gradually.
  • Fertilizers have different formulas for different uses.
    • 10-52-10 is used for newly planted or divided plants.
    • 15-30-15 is used to give perennials a boost in the spring and encourage flowering. It can also be used for regular fertilization applications (every two weeks). 
    • Pink granular fertilizer is used to enhance new spring growth and it can be used in conjunction with 15-30-15. 
  • In the fall, dress beds with compost or bone meal to add nutrients to the soil for growth in the following spring.


Some plants – peonies, delphiniums, hollyhocks, lupines, monkshood, bleeding hearts, and Shasta daisies, for example – tend to flop or break unless they have something to support them. Staking can provide these plants with the support they need. 

Insert stakes, rings or cages in place when the plant starts to grow in the spring. As the plants grow, their foliage will cover these structures and only the plants will be visible in the garden.



Weed removal is important because they compete with plants for the soil’s nutrients and water and they can harbour pests and diseases that can be harmful to the plants. Adding a layer of mulch on top of the soil will inhibit weed germination and allow for easy removal of any rooted weeds.


Winter Protection:

It is important to protect the soil from cold winter temperature and freezing and thawing in order to ensure plant growth in the spring.
  1. After a hard frost, apply a 3-4 inch layer of winter mulch around the base of the plant. It is best to use shredded bark, straw, and/or shredded leaves. 
  2. In the spring, as temperatures rise and the soil warms, gradually pull back the mulch from the plant’s base.