How to grow Perennials

Growing Perennials

Reliable plants that return year after year

Perennials are the backbone of a well-planned garden. They grow, flower and die back seasonally, returning year after year with fresh growth and renewed colour. With a huge range of forms, from flowering favourites to foliage stars, perennials bring rhythm, structure and long-term value to garden beds and borders.

Choose varieties suited to your climate and garden conditions and perennials will reward you with dependable performance and improving displays over time.

Get the 'Grow How'

Perennials are about patience and good foundations. While they may take a little time to settle in, strong roots and healthy soil ensure better flowering and longer life. Once established, many perennials are surprisingly low-maintenance.
Planting Procedure
Fertilising and Care
Pests and Diseases
Garden Uses

THE BASICS:

Good preparation sets perennials up for long-term success. Well-prepared soil and correct spacing help plants establish and mature without competition.

Quick Tips:

  • Plant in the correct light conditions for the variety
  • Prepare soil with compost or organic matter
  • Space plants to allow for mature size
  • Prepare the soil by digging over deeply with garden fork.
  • Add superphosphate or bone meal as root stimulating fertiliser and good compost at recommended rates.
  • Dig into soil and mix thoroughly.
  • Rake soil to correct level.
  • Remove the plant from pot or nursery bag.
  • Carefully untangle some of the matted roots where necessary.
  • Dig a hole large enough to accommodate the root ball comfortably.
  • Place plant in hole and fill in around the root ball and firm soil down gently.
  • Make sure the plant is buried at the same level as it was growing in pot or bag.
  • Once planting is complete water well to settle in.

 

KEEP THEM HAPPY:

Regular care keeps perennials performing well. Feeding and maintenance encourage strong growth and repeat flowering.

Quick Tips:

  • Cut back spent flowers to encourage new growth
  • Divide overcrowded plants every few years
  • Mulch to protect roots and improve soil health
  • Apply a layer of mulch (pine bark is best) on the surface of the soil around the perennials to supress weed growth and reduce watering.
  • Regular fertilising with a balanced granular plant food every 4 to 6 weeks from spring to autumn ensures healthy growth.  A 3:1:5 or 5:1:5 formula is ideal.
  • Pinch out the growth tips of tall, lanky plants to encourage basal branching (only applies to certain plants).
  • Dead head spent flowers by removing the flower stalk and developing seed capsule.
  • Prune back any plants that get straggly or untidy.
  • Cut back spent perennials in late autumn.
  • Split or divide overgrown clumps immediately after this.
  • Apply a new layer of mulch after the autumn clean up.

 

GOOD TO KNOW:

Healthy plants are far more resilient. Most problems can be avoided with correct planting and spacing.

Quick Tips:

  • Ensure good airflow around plants
  • Use suitable treatments only when needed
  • Aphids gather on the soft new growth tips and suck the sap out of the plant.  Control with general purpose insecticide.
  • Caterpillars, beetles and grasshoppers chew the leaves.  Treat with a systemic insecticide (only suitable for use on non-edibles).
  • Red spider mites are a problem on some plants, especially in summer.  Use a suitable miticide.
  • Fungal diseases like mildew and rust on the leaves.  Spray with a broad-spectrum fungicide.
  • Cutworms chew seedlings off at ground level.  Apply cutworm bait immediately after planting or drench newly planted seedlings with general insecticide.
  • Snails and slugs are nocturnal pests that eat the lush young leaves.  Apply snail bait at regular intervals especially early spring.

 

GREAT FOR:

Perennials create structure and flow in the garden. They form the framework that seasonal plants can be layered into.

Quick Tips:

  • Use as repeat planting for visual rhythm
  • Combine with shrubs and annuals for year-round interest
  • Excellent for long-term garden planning
  • Many varieties attract bees and butterflies
  • Ideal for planting in mixed herbaceous borders.
  • Important plants in cottage gardens.
  • Useful for filling up space amongst shrubs and roses.
  • Some work well in mixed pot plantings along with annuals.
  • Clump forming types are used as groundcover in mass plantings or to stabilise banks.
  • Many perennials are grown as cut flowers.

 

Shopping List

  1. Tools for preparing the soil and planting.
  2. Compost or kraal manure to dig into the soil.
  3. Fertiliser to promote root growth (superphosphate or bone meal).
  4. Pruning shears to assist if dividing perennials from the garden.
  5. Watering can or hosepipe.
  6. Mulch material for spreading after planting.
  7. Snail bait.
  8. Cutworm bait.
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DISCLAIMER:  The information presented on this website is intended solely as a general guide. We neither endorse specific plant varieties over others nor claim expertise in stock performance. All information is believed to be accurate, based on private inquiries and experiences, and is provided in good faith. Blackwood’s, including its employees, disclaims any responsibility for harm, loss, cost, or damage arising from the use or reliance upon any information on this website, especially if any part of the information proves to be inaccurate or incomplete. Please note that the displayed photos are not representative of current stock but are used for illustrative purposes only.