Course Content
NINE lessons as follows:
1. Scope and Nature of Flowering Shrubs
- Why Grow Shrubs
- Choosing Appropriate Shrubs
- Classification and Naming
- Shrub Nomenclature
- How the Genus Rosa is Split Up
- Broad Rules when Writing Plant Names
- Ranks of Classification
- Dicotyledons and Monocotyledons
- Dahgren System for grouping families into orders
- Cronquist System
- Continuing Change
- Rosids
- Order Rosales, Order Malphigiales, Order Sapindales, Order Malvales, Order Saxifragales
- Asterids (Asteranae)
- Myrtles (Myrtiflorae)
- Solanales
- Cornales
- Dipsacales
- Boraginales
- Rules for Identifying Plants
- Botanical Key Concept
2. How to Establish and Care for Shrubs
- Choosing Shrubs
- Preparing the Garden
- Consider the Site
- Getting Soil Ready
- Time of Planting
- Planting Shrubs
- Staking
- Shrub Maintenance
- Good Hygeine
- Watering
- Nutrition
- Mulching
- Pruning
- Inspecting for Pest and Disease
- Common Problems - pests, diseases, environmental issues, weeds
- Controlling Pest and Disease
- Working with the Space Available
- Controlling Roots
- Controlling plant growth
3. The Rosids (Superorder Rosanae)
- Superorder Rosanae - fabids, Malvids & others
- Rosaceae : Chenomeles, Cotoneaster, Kerria, Pyracantha, Rosa, Spiraea
- Rhamnaceae : Ceonothus
- Eleagnaceae : Eleagnus
- Saxifragaceae – Deutzia, Hydrangea,
- Celastraceae – Euonymus
- Euphorbaceae – Codiaeum
- Hypericaceae – Hypericum
- Cistaceae -Cistus
- Malvaceae – Hibiscus
- Thymelaceae - Daphne, Pimelea
- Rutaceae -Boronia, Choisya, Coleonema,Correa, Crowea, Fortunella, Murraya
4. The Asterids (Superorder Asteranae)
- Introduction to Asteranae: Lamids & Campanulids
- Differences between Asterids and Rosids
- Asterid Shrub Families
- Acanthaceae - Justicia/Beloperone, Barleria, Pachystachus, Aphelandra, (Order Lamiales)
- Lamiaceae -Lavendula, Ocimum (Basil), Prostanthera, Salvia, Rosmarinus, Westringia, Leonotis, Prostanthera (Order Lamiales
- Scrophulariaceae -Hebe, Eremophila, Myoporum, Veronica (Order Lamiales)
- Verbenaceae -Aloysia, Clerodendrum, Duranta, Lantana, Verbena (Order Lamiales)
- Oleaceae – Forsythia, Ligustrum, Jasminum, Syringia (Order Lamiales)
- Rubiaceae – Bouvardia, Coprosma, Gardenia, Luculia, Musseanda, Pentas (Order Gentiales)
5.Ericales
- Introduction
- Ericaceae -Andromeda, Rhododendron (includes Azaleas), Calluna, Erica, Kalmia, Pieris, and Vaccinium (Blueberry).
- Theaceae - Camellia, Gordonia, and Stewartia.
- Clethraceae - Clethra
- Syracaceae - Halesia and Styrax
6. Significant Shrubs in Myrtiflorae
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Myrtiflorae
- Introduction
- Lythraceae – Cuphea, Pomegranate
- Myrtaceae - Bauera, Callistemon/Melaleuca, Leptospermum,
- Melastomaceae – Tibouchina, Melastoma, Medinilla, Osbeckia
- Onagraceae – Fuchsia
7. Corniflorae and Solaniflorae
- Introduction
- Caprifoliaceae -Abelia, Kolkwitzia, Lonicera, Viburnum, Weigelia (Order Dipscales, Superorder Corniflorae)
- Cornaceae - Cornus (Order Cornales)
- Hydrangeaceae - Hydrangea (Order Cornales)
- Boraginaceae – Heliotropum (order Boraginales (superorder Solaniflorae)
- Solanaceae - Browallia, Brunfelsia, Cestrum, Solanum (superorder Solaniflorae)
8. Other Important Shrubs
- Berberidaceae -Berberis, Mahonia, Nandina (Ranunculales)
- Buxaceae – Buxus (Buxaceae)
- Fabaceae – Genista, Pultenaea, acacia (Fabales (superorder Fabiflorae)
- Plumbaginaceae – Ceratostigma (Plumbago) (Caryophyllales)
- Polygalaceae – Polygala (Fabales)
- Proteaceae – Banksia, Grevillea, Protea (Proteales, superorder Proteanae)
9. Plant Selection and Design
AIMS
- Discuss the scientific classification, scope and nature of shrubs, and compare some of the differences in appearance characteristics between important plant orders and families that encompass horticulturally significant shrubs.
- Describe different techniques used to prepare for planting, plant, nurture and maintain shrubs in different horticultural situations.
- Identify and describe a variety of different commonly grown flowering shrubs that are related to roses, in that they are on occasion classified into the taxonomic order Rosales or the superorder Rosanae.
- Identify and describe a variety of different commonly grown flowering shrubs that are related to lavender, in that they are on occasion classified into the taxonomic superorder Asteranae.
- Identify and describe a variety of different commonly grown flowering shrubs that are related to rhododendrons, in that they are on occasion classified into the taxonomic order Ericales.
- Identify and describe a variety of different commonly grown flowering shrubs that are related to Leptospermums, in that they are on occasion classified into the taxonomic order Rosales or the superorder Myrtiflorae.
- Identify and describe a variety of different commonly grown flowering shrubs that are related to Viburnum and Cestrum, in that they are on occasion classified into the taxonomic groups Corniflorae and Solaniflorae.
- Identify and describe a variety of different commonly grown flowering shrubs that are from significant plant families not studied earlier in this course.
- Select appropriate shrubs and explain how to use them in different places.
Learning Shrub Plant Taxonomy is a Window to Identifying and Growing them
Understanding and using this scientific approach to plant naming is by far the best way of gaining an understanding of the differences between various shrubs; and building your ability to identify and grow them.
Many of the most grown shrubs in horticulture are related to each other. The divisions of clades, super-orders, and to a lesser degree orders, are not always immediately obvious. Despite changes and the appearance of contradictions in what you might read; this imperfect scientific system of classifying plants is the best we have. It is extremely useful for understanding how particular plants fit into the grand scheme of things. This understanding helps to do two things much easier:
- Identify plants and remember their names, and,
- Be informed about how to grow plants. Plants tend to perform similarly to those plants they are related to and classified closely to.
Why Grow Shrubs?
There are many reasons why people choose to grow shrubs. The value of shrubs may be summarised as follows:
- Environment – Shrubs can moderate temperature. In cities plants will slow temperature change, reducing the heat island effect. Shrubs can be mitigate flooding and erosion; reduce glare from sunlight, and control wind intensity and direction.
- Wildlife – Flowers and foliage of shrubs provide food and protection for animals, including mammals wildlife, bees and butterflies. Many birds and insects feed on nectar from shrubs. Certain animals have developed a particular synergy with certain plant genera (eg. swallowtail butterflies that only lay eggs on certain Rutaceae family plants). Shrubs provide habitat and nesting sites for smaller birds. Thorny and dense shrubs provide them with shelter from predators.
- Livestock – Many shrubs can provide nutritious foraging material for livestock. Cattle, goats, and sheep especially are all foragers of various shrubs. These ruminant livestock have four-chambered stomachs which makes digestion of shrubby plant materials possible through a process of fermentation.
- Aesthetic value – Flowering shrubs can be used to create an aesthetic affect, making a garden more pleasant to be in or to observe from a distance. Shrubs may be used to provide colour and texture; or combined and treated in various ways to create a mood, feeling or beauty.
- Functional value - Shrubs are sometimes used for more practical or functional purposes, such as screening an undesirable view, providing privacy, or directing the flow of foot or vehicular traffic
- Cut flowers – Some shrubs are cultivated commercially for cut flowers, including Roses, Protea, Banksia, Buddleia, Bouvardia, Gardenia, Camellia, Hydrangea, Forsythia and Lilac.
- Cropping – Some shrubs are grown and harvested for various products. Certain edible berries (eg. red currants, blueberries) come from shrubs. Green and black tea is harvested from a Camellia. Lavender and a range of other herbs are grown to produce valuable scented oils. Many other shrubs may be grown for harvesting.