Course CodeVHT111
Fee CodeS2
Duration (approx)100 hours
QualificationStatement of Attainment

Become an Expert in Growing Iris

Learn to identify, grow and use Irises.

Explore a passion, start a business or improve your opportunities for working in nurseries or gardens.

Expand your horticultural expertise.


How are Iris Classified?

The iris genus can be divided into three broad groups as follows:

1. Bulbous
2. Tuberous
3. Rhizomatous

Bulbous Division

  • These plants that produce bulbs
  • These are divided into the Xiphium Group (which includes Dutch Iris) and others

Tuberous Division

  • These plants that produce tubers
  • This includes Nephalensis species

Rhizomatous Division

  • These plants that produce rhizomes
  • Divided into three sub divisions:
  • Apogon Iris (Beardless)  Includes Sibirica, Spuria, Californian, Hexagona, Lavaegata and other groups.
  • Evansia Iris (Crested)   -These are generally the earliest flowering Iris (late winter in temperate climates)
  • Pogon Iris (Bearded)  Includes dwarf bearded  group, germanica group and other bearded iris


Lesson Structure

There are 8 lessons in this course:

  1. Introduction
    • Review of the system of plant identification
    • Physiology
    • Information sources
  2. Culture
    • Planting
    • Staking
    • Mulching
    • Watering
    • Feeding
    • Pruning, etc.
  3. Propagation and Hybridisation
    • Seed
    • Division
    • Separation
    • Tissue Culture
    • Review of selected species/hybrids.
  4. Review of Major Types of Irises
    • Bearded
    • Louisiana
    • Siberian
    • Dutch
    • English Spanish
  5. Pest and Diseases
    • Review of species from contrasting environments
    • Review of various health problems
  6. Water Irises
    • Review of species
    • Irrigation
    • Irises in Hydroponics
  7. Landscaping with Irises
    • Garden Design
    • Cottage Gardens
    • Using Colour
    • Review of more Iris species
    • Flower bed design
  8. Harvest, Post Harvest, Exhibiting and Quality

Each lesson culminates in an assignment which is submitted to the school, marked by the school's tutors and returned to you with any relevant suggestions, comments, and if necessary, extra reading.


  • Explain the taxonomy of Iris
  • Explain the normal cultural requirements for different types or Iris.
  • Breed and propagate Iris.
  • Describe the identification and culture of a range of commonly cultivated Iris.
  • Manage pest and disease problems on Iris
  • Manage water requirements for Iris
  • Discuss cultivation of Iris hydroponically
  • Explain the use of Irises in landscaping
  • Describe the production of Iris as a cut flower crop, in particular the harvest and post harvest.


Growing Iris Tips from our Tutors

There are over 200 species of Iris and many thousands of cultivated varieties.
  • There are species which will grow well in most temperate and sub tropical climates; and some that will grow in climates even wider than that.
  • Some will grow totally submerged in water, others will withstand extended periods of dry.
  • Some tolerate snow and frost, some will tolerate extreme heat.
  • Some like heavy shade; others grow well in full sun.

It is important to choose the appropriate type of iris for the conditions you plan to grow it in.

There is no “ideal” location for “all” irises.


  • Irises occur naturally in both sub arctic and sub tropical climates
  • Irises can be found growing naturally at very high altitudes above the snow line, and also close to sea level.
  • There are iris species that are native to deserts, and other species that are native to swamps.
  • There are species which must have very well drained and dry soil at least part of the year, and others that need soil rich in humus and saturated with water.
  • Some grow in alkaline soils, while others will die if the soil is not acidic.

If you are going to select the right iris for the right position, you need to get to know the differences between species and cultivars, and understand the factors that characterise the places you wish to grow them.

Consider the Site
 Does it have any particular problems which should be treated?

  • Hard clay soils need to be loosened up by cultivation, or by adding soil conditioners such as lime or gypsum, or by incorporating organic matter, such as well rotted manures and compost.
  • Sandy soils can sometimes dry out too easily or be low in nutrients. To overcome these problems add well rotted manures or compost, or wetting agents.
  • Check soil pH (the degree of acidity or alkalinity). Most plants prefer a slightly acid or neutral soil (pH of about 6 to 7.5). Most Iris prefer a pH that is a little more acid than this (less than 6), but will tolerate up to neutral (7). Plants that prefer a pH slightly more alkaline (eg Lavender) may not grow as well alongside iris.  Simple test kits can be readily obtained from nurseries, garden centers, etc. You can then either choose plants that like the pH of your soil/growing media, or you might alter the pH to suit the plants you wish to grow. pH can be raised by the addition of lime, or lowered by the addition of acidifying materials such as Manures, Sulphate of Ammonia, or Sulphur powder (only for small areas as it is relatively expensive).
  • Provide wind breaks or channel winds with fences or planting, to both protect tender plants and ensure good ventilation (If the garden is totally enclosed, air movement is restricted, and that can result in an increase in diseases.
  • If necessary, select plants to grow that will tolerate or even prefer periods of shade.

Many Iris Species will Respond to Better Soil

Before you plant any iris in a new garden, make sure the soil is in a condition appropriate to the species being grown.

This may involve making sure drainage, nutrition, the soil type (e.g. sandy, clayey), and the structure of the soil is suitable for the plants you wish to grow. It may involve laying drainage pipes; applying fertilisers, gypsum (to improve the structure of clay soils) or lime; or digging in manure and compost. Always thoroughly eliminate any existing weeds.

Iris Breakers
Iris histrioides Major
Iris reticulata Edward
Iris Pogo
Iris setosa
Iris zagrica

Meet some of our academics

Adriana Fraser Adriana has worked in horticulture since the 1980's. She has lived what she preaches - developing large gardens and growing her own fruit, vegetables and herbs and making her own preserves. In 1992 she formalised her training by graduating with a certificate in horticulture and a few years later, completed a Advanced Diploma in Horticulture amongst other qualifications. Adriana has worked across a broad spectrum of the horticulture industry and has developed a strong network of contacts in horticulture around Australia and beyond. She has written and contributed to many books and magazine articles. She has a passion for plant knowledge and sustainability and a natural understanding of how people learn about horticulture and has taught in various institutions and organistions as well as ACS. Adriana has been a tutor with ACS since the mid 90's and based on the feedback from past students has been an overwhelming success in helping people develop their skills and further careers in horticulture.
Diana Cole Dip. Horticulture, BTEC Dip. Garden Design, Permaculture Design Certificate, B.A. (Hons)-Geography, Diploma Chartered Institute of Personnel & Development Diana has been an enthusiastic volunteer with community garden and land conservation projects since the 1980's. She has worked full time in horticulture since 2001, as a nursery manager, landscape and garden consultant, and a horticultural teacher (both with ACS and in the classroom with a local college where she lives in England).
Rosemary Davies Rosemary trained in Horticulture at Melbourne Universities Burnley campus; studying all aspects of horticulture -vegetable and fruit production, landscaping, amenity, turf, aboriculture and the horticultural sciences. Initially she worked with the Department of Agriculture in Victoria providing advice to the public. Over the years she has taught horticulture students, worked on radio with ABC radio (clocking up over 24 years as a presenter of garden talkback programs, initially the only woman presenter on gardening in Victoria) and she simultaneously developed a career as a writer. She then studied Education and Training, teaching TAFE apprentices and developing curriculum for TAFE, before taking up an offer as a full time columnist with the Herald and Weekly Times and its magazine department after a number of years as columnist with the Age. She has worked for a number of companies in writing and publications, PR community education and management and has led several tours to Europe. In 1999 Rosemary was BPW Bendigo Business Woman of the Year and is one of the founders and the Patron, of the Friends of the Bendigo Botanic gardens. She has completed her 6th book this year and is working on concepts for several others. Rosemary has a B Ed, BSc Hort, Dip Advertising & Marketing
Yvonne SharpeRHS Cert.Hort, Dip.Hort, M.Hort, Cert.Ed., Dip.Mgt. Over 30 years experience in business, education, management and horticulture. Former department head at a UK government vocational college. Yvonne has traveled widely within and beyond Europe, and has worked in many areas of horticulture from garden centres to horticultural therapy. She has served on industry committees and been actively involved with amateur garden clubs for decades.

Check out our eBooks

Growing & Knowing Flowering BulbsGet to know your flowering bulbs and the optimum growing conditions for each with the Growing and Knowing Flowering Bulbs ebook. With 187 pages of hints and tips on growing flowering bulbs, as well as stunning colour pictures, this is an essential tool for your gardening kit! This ebook is ideal for gardeners, students and professional horticulturalists and includes a colour glossary of flowering bulbs.
HerbsHerbs are fascinating plants, mystical and romantic. They have a rich history dating back centuries. Used by monks, apothecaries and ‘witches’ in the past, herbs are undergoing a revival in interest. They are easy to grow, scented, culinary and medicinal plants. In a formal herb garden or peppered throughout the garden, herbs rarely fail! Find out how they are used as medicines, for cooking, perfumes and more.
Organic GardeningFor decades farmers have relied upon chemicals to control pests and diseases in order to produce saleable crops. In the ornamental, vegetable and fruit gardens reliance on chemical controls has also been the mainstay for many gardeners.
Scented PlantsScented plants can be either a delight or a curse. For many people, there is nothing more pleasing than a garden filled with fragrance, but for others who suffer allergies, certain plants can make them physically ill; sometimes very seriously.



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