GREEN ROOF AND WALLS COURSE
Learn to develop appropriate and functional roof and vertical gardens, for residential, commercial and public landscapes.
Green walls and roofs are increasingly popular in landscaping and environmental management for various reasons, including:
- Greening areas where there is lack of space for a more extensive garden
- Improving aesthetics of unsightly places
- Improving the environment (eg. Reduce glare, modify temperature, filter air pollutants, reduce water run off and mitigate flood problems, etc)
- Urban farming –growing crops in an urban area
There are 9 lessons in this course:
Scope & Nature of Roof and Vertical Gardens
Construction Functional and Appropriate Vertical and Roof Gardens
Climbing Plants and Structures for climbing
Plants Suited to Roof and Vertical Gardens
Adaptations for Other Plants in Roof and Vertical Gardens
Maintenance –watering, pest control
Applications/Landscaping –Roof Gardens
Applications/Landscaping –Vertical gardens
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.
Discuss the nature and scope of vertical gardens and roof gardens in horticulture today.
Explain engineering considerations involved with the building of vertical and roof gardens, both on small and large scale projects.
Select appropriate materials and plan the way in which the non living components of the garden is created, in order to achieve an appropriate and sustainable installation.
Select appropriate climbing plants for creating vertical or roof gardens, and determine appropriate strategies to cultivate those plants, in a variety if different situations.
Select appropriate plants for use in vertical or roof gardens, which are tolerant of the adverse growing conditions, having natural adaptations to growing under conditions that are encountered in these gardens.
Select and plan the cultivation of plants that lack natural adaptations to growing on roofs or vertical gardens; but which are none the less required to grow in these adverse conditions;
Explain a range of container growing techniques, in a range of different roof and vertical gardens, that may be used with a selection of different types of plants.
Identify and evaluate problems with vertical and roof gardens, and compare options for solving those problems
Plan the development of roof gardens for both small and large scale applications.
Plan the development of vertical gardens for both small and large scale applications.
Succulents are Ideal for Green Walls and Roofs
Many low growing succulents are suited to green walls – a greater variety can be used on roofs because you are less limited in the height of the plant (tall plants are obviously unsuited to wall growing.
Sedums are a Good Example
Sedums (Stonecrop) are mainly low growing plants there are over 600 species and many more named varieties. They include plants that may grow no taller than 2 or 3cm, to plants reaching 30cm in height. Leaf shapes and colours can be extremely variable. Some are evergreen, others are herbaceous. Most are easy to propagate from cuttings. The lower growing, spreading, evergreen sedums are often used for roof gardens or wall gardens.
Cultivated species known to have successfully been used in roof or vertical gardens include:
S. acre (common name: Golden Carpet) - a creeping plant sometimes to 12cm tall, mat forming, bright yellow flowers in summer, A golden foliage cultivar is also grown. It can be invasive.
S. album (syn. S. balticum) – mat-forming plant with flower heads reaching 87 to 20 cm tall. White flowers; though there are many cultivars that are differentiated by variations in foliage and flower colour.
S. allantoides – flower heads to 30cm tall.
S. floriferum – ascending to decumbent (lying down) growth habit, yellow flowers in summer.
S. kamtschaticum – elongated rhizome often supporting several weaker stems, yellow flowers, variegated leaf form also.
S. mexicanum – decumbent growth, tuberous roots, erect flower stems to 80cm; mostly dark green leaves, but forms exist with variations in leaf colour, flowers are greenish occurring late summer.
S. pachyphyllum (common name: Jelly Beans) - to 30cm tall, cylindrical leaves often have a reddish tip, Yellow flowers in winter and spring.
S. reflexum - decumbent growth habit, linear leaves, golden yellow flowers, Reaches 15 to 35cm tall.
S. x rubrotinctum (common name: Christmas Cheer) - probably occurred as a garden hybrid, now widely cultivated. Branching, spreading growth habit, commonly low, but occasionally to 30cm tall; thickened lush green leaves with reddish tones, yellow flowers in winter.
S. sexsangulare – green leaves, yellow flowers, decumbent at base, stems 7-15cm long.
S. spirium - dark green leaves sometimes reddish tones, decumbent at base; flowers pink to purplish, several variable cultivars are grown.
S. ternatum - white flowers in spring.
Wall and Roof Gardens Do Need Maintenance
With good design and careful plant selection, you can dramatically reduce the potential problems and level of maintenance needed for a roof or vertical garden. You will never eliminate maintenance though.
This course helps you to understand not only how to create a roof or wall garden in the first place; but also how to make appropriate choices to ensure it continues as a viable and sustainable feature well into the future.
All gardens require regular maintenance to help plants to thrive and look at their best. Vertical walls and roof gardens are no exception. Whilst a minimalist roof garden based on a xeriscape theme with few plants, mainly cacti and succulents, and pebble mulches is low on maintenance compared to a lush green wall with cascading plants and salad crops - it still needs some attention. Maintenance tasks include things like:
- Watering where needed - checking the functioning of computers in irrigated gardens, cleaning out filters, inspecting for broken or damaged drip ends and soaker pipes.
- Mulching - to prevent excess moisture loss, and to maintain a stable root temperature environment.
- Pest and disease control - inspecting plants for the presence of undesirable insects and fungal or bacterial infections, and treating where necessary.
- Maintaining humidity - too much humidity may promote fungal infections. Too little can cause some plants to lose too much water and wilt.
- Protecting from exposure to drying air from air conditioning and heating vents and flue pipes or winds.
- Ensuring sufficient light from shading by structures or other plants.
- Preventing nutrient deficiencies and toxicities through fertilising regularly.
- Pruning plants to maintain optimal health and-or to encourage fruiting and flowering.
- Removing weeds from containers to prevent them competing with the plants for water and nutrients.
OUT OF SITE/OUT OF MIND
When roof or vertical gardens are in high and less frequented places; problems with the plants can tend to go unnoticed more frequently, or for longer.
If a roof garden is not visited routinely, weeds can grow, pests and diseases may take hold, and plants can die before problems are noticed. Birds may visit a high roof garden more often than people; and you can sometimes have problems with crows or other birds pulling out plants, or feeding on fruits and vegetables. Regularly programmed inspections are an important part of a maintenance programme.
Sometimes the best way may be to plant hardy plants, decide to accept a certain level of disease and plant loss, and adopt a philosophy to let nature take its course. As long as something is growing, perhaps it does not always matter whether it is what you originally intended to grow. A planting theme may be adapted to include the plants which do best in the location.
In other cases, where a specific theme or type of plant is desired, then it may well be necessary to manipulate the environment in order to grow it. It may be possible to move plants which become quickly sun scorched so that they are in a more shady position, or to screen them, or place to relocate them beneath the canopy of a taller plant. Checking regularly on plants which are less visible is particularly important within the first twelve months whilst they are acclimatising and becoming accustomed to their new environment.
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