TOPIC 6_SPECIALIZED PLANTING (GREEN WALL & GREEN ROOF)

TOPIC 6: SPECIALIZED PLANTING

Learning Outcomes

  • Green Roof and Green Wall Definitions: Understand what constitutes a green roof and green wall.

  • Types and Components: Identify different types and components associated with green roofs and walls.

  • Benefits and Concerns: Explain the advantages offered by these systems as well as potential concerns.

  • Installation and Maintenance: Describe the basic steps for installing and maintaining green roofs and walls.

Specialized Planting Overview

Definition

Specialized planting involves selecting and cultivating specific plants that are not only suited to unique environmental conditions but also fulfill functional requirements and aesthetic goals in a landscape. This practice ensures an optimized growth environment, biodiversity, and sustainability in design.

Environmental Considerations

  • Climate: Choose plants that thrive in local conditions, considering temperature ranges, humidity levels, and seasonal variations.

  • Soil: Select plants based on soil types (e.g., sandy, clay, loamy) and conditions (pH levels, organic matter content).

  • Light: Ensure plant choices correspond with light availability such as full sun, partial shade, or full shade conditions to enhance plant vitality.

Functional Requirements

  • Erosion Control: Use plants with robust root systems, such as grasses and native perennials, to stabilize soil and prevent erosion on slopes or in exposed areas.

  • Stormwater Management: Employ plants that are capable of absorbing and filtering rainwater, like native ferns and wetland species, to promote natural water management and reduce runoff.

  • Habitat Creation: Select plants that provide ecosystems for local wildlife, which bolsters biodiversity and creates habitats for pollinators and other beneficial creatures.

Aesthetic Goals

  • Color and Texture: Choose visually appealing plants with a variety of flower colors and foliage textures, enhancing the visual interest and seasonal changes of the landscape.

  • Seasonal Interest: Opt for plants that provide visual interest throughout the year with varied blooming periods and foliage changes, ensuring that some form of beauty is present in all seasons.

  • Thematic Design: Implement plants that align with specific garden themes such as coastal, woodland, or formal gardens, creating cohesive and impactful designs.

Green Roofs

3.1 Definition

Green roofs are gardens located on the roof or podium deck of a building, designed to provide environmental, social, and economic benefits. They can help manage stormwater, insulate buildings, and create green space in urban environments.

3.2 Categories/Types

  • Intensive Green Roofs:

    • Have deep soil layers (200-2000mm).

    • Suitable for a wide variety of plants, including flowers, shrubs, and even small trees.

    • Accessible for maintenance and recreational use, providing space for human enjoyment.

  • Extensive Green Roofs:

    • Characterized by shallow soil layers (50-150mm).

    • Planted with low-growing, drought-resistant plants, such as sedums and mosses.

    • Require minimal maintenance and are suitable for roofs with less load capacity.

3.3 Basic Components

  • Waterproof Barrier: Prevents moisture escape and protects against root damage from excessive water.

  • Protection Mat: Shields the roof from mechanical damage, extending the life of the roof surface.

  • Irrigation & Drainage: Ensures proper water management, preventing waterlogging or drought conditions for plants.

  • Root Barrier: Protects building structures from plant roots while retaining soil moisture for plant health.

  • Substrate/Media: Supports plant growth, which can be either organic (like compost) or inorganic (like expanded clay pellets).

  • Plant Material: Ideally, the selection includes site-specific, preferably native plants that require low maintenance and are resilient to local conditions.

3.4 Installation Steps

  1. Waterproofing the roof surface.

  2. Installing a geotextile/filter layer to separate components.

  3. Adding drainage systems to ensure proper water movement.

  4. Placing root barriers to protect underlying structures.

  5. Filling the area with a soil mixture suitable for plant growth.

  6. Installation of hardscape (paved areas, paths) and softscape (plants).

  7. Finishing touches to enhance aesthetics (decorative elements, art).

3.5 Benefits and Concerns

  • Benefits: Improved insulation and energy efficiency, increased biodiversity, aesthetic enhancement of urban areas, and potential to reduce heat island effect.

  • Concerns: Maintenance costs can be higher than conventional roofs, potential for water damage if not properly managed, and drainage issues may arise if systems are poorly designed or maintained.

Green Walls

4.1 Nomenclature

Also known by terms like bio-wall, eco-wall, living wall, and vertical garden; each term conveys a slightly different aspect of green walls but generally refers to vertical structures designed to support vegetation.

4.2 Definition

Vertical structures designed to support vegetation through various systems that allow plants to thrive on walls, often incorporating advanced irrigation and drainage solutions.

4.3 Types & Classification

  • Direct Green Facade: Vegetation grows directly into the facade, where plants are integrated into the building’s architecture.

  • Indirect Green Facade: Utilizes trellising systems where climbing plants establish growth paths.

  • Modular Systems: Includes trays, vertical planters, or flexible bags for planting; these systems are typically pre-planted and easy to install.

4.4 Basic Components

  • Supporting Structure: Foundation framework to prevent vegetation from falling.

  • Growing Media: Anchors plants onto vertical surfaces, consisting of soil or hydroponic substrates.

  • Plant Material: Selection of plants that are effective in vertical growing conditions and are chosen based on local climate adaptability.

  • Drainage & Irrigation Systems: Critical components that supply necessary water and nutrients for healthy plant growth.

4.5 Installation Steps

  1. Choose a suitable wall structure that can support the weight of the plants and growing medium.

  2. Apply waterproofing treatment to protect from water damage.

  3. Set up and connect the irrigation system, ensuring it provides uniform coverage.

  4. Mount the green wall panels/modules securely.

  5. Select appropriate plants based on environmental conditions and install them in the growing media.

4.6 Advantages and Risks

  • Advantages: Boosts property aesthetics, enhances air quality through CO2 absorption, improves thermal insulation, and can reduce energy costs.

  • Risks: Requires careful maintenance to avoid issues like water management failures or pest infestations, and potential structural issues can arise if water is not managed properly.

4.7 Maintenance Tasks

  • Regularly check for weeds, diseases, and overall plant health, addressing issues promptly.

  • Ensure adequate irrigation and monitor for blockages in the water delivery system.

  • Replant or replace plants as necessary to maintain aesthetic continuity and biodiversity.

Examples of Projects

  • Malaysia: Parkroyal KL - A collection known for its warm ambiance and integrated greenery.

  • Malaysia: Tamarind Square - Notable for its community-centric green building design.

  • Worldwide: Milan, Italy - Home to the world's largest vertical garden, expanding on the concept of green architecture.

  • Worldwide: Gardens by the Bay, Singapore - Showcases innovative green building practices and integrates ecological design into urban spaces.