Unit II of Landscaping

Ornamental Trees: Selection, Propagation, Planting Schemes, and Canopy Management

Ornamental trees form the structural framework of landscapes. Their size, shape, colour, and seasonal attributes influence the overall aesthetic and functional value of gardens, parks, avenues, and institutional campuses.

Selection of Ornamental Trees

• Adaptability to local soil and climate conditions.
• Growth habit: tall, medium, dwarf; evergreen or deciduous.
• Aesthetic features: flowers, foliage, bark colour, fragrance, canopy shape.
• Purpose: shade, screening, avenue planting, specimen planting, windbreaks.
• Low maintenance, pest- and disease-resistant varieties.
• Non-invasive root systems for planting near buildings or pavements.

Propagation of Ornamental Trees

• Sexual propagation: seeds (e.g., Delonix regia, Polyalthia longifolia, Cassia species).
• Asexual propagation:
  • Cuttings (Bougainvillea, Ficus spp.)
  • Air layering (Ficus benghalensis, Ficus benjamina)
  • Grafting (Cassia fistula, Bauhinia spp.)
  • Budding (Rosa trees formed by budding on rootstocks)

Planting Schemes for Trees

• Avenue Planting: Trees spaced at uniform distances along roads; symmetrical arrangement preferred.
• Specimen Planting: A single tree highlighted in lawns or entrances.
• Group Planting: Trees of similar or contrasting species planted in groups for mass effect.
• Screen or Barrier Planting: Dense foliage trees planted to block unwanted views.
• Eco-restoration Areas: Mixed indigenous species for ecological balance.

Canopy Management

Proper canopy architecture ensures healthy growth, safety, and aesthetic value.

• Training: Establishing the desired shape during young stages.
• Pruning: Removing diseased, crossing, or excessive branches.
• Crown lifting: Removing lower limbs to improve clearance.
• Crown reduction: Reducing tree height/spread for safety and symmetry.
• Crown thinning: Improving airflow and light penetration.

Shrubs and Herbaceous Perennials: Selection, Propagation, Planting Schemes, and Architecture

Selection of Shrubs

• Growth habit: dwarf, medium, tall shrubs.
• Flowering season: continuous or seasonal bloomers.
• Fertilizer and water requirement compatibility.
• Use: hedges, borders, screening, foundation planting.

Propagation of Shrubs

• Stem cuttings (Duranta, Hibiscus, Lawsonia, Jatropha).
• Layering (Jasminum, Bougainvillea).
• Division and suckers (Chrysanthemum, Lantana).

Planting Schemes

• Hedges and Borders: Dense shrubs arranged linearly.
• Mass Planting: Large beds using colourful shrubs for visual impact.
• Mixed Shrubbery: Combination of shrubs with varied shapes, textures, and flowering times.
• Foundation Planting: Shrubs planted along building edges.

Architecture of Shrubs and Perennials

• Rounded shrubs for soft landscape edges.
• Columnar shrubs for vertical accents.
• Spreading shrubs for ground coverage.
• Perennials provide long-term flowering and structural stability.

Climbers and Creepers: Importance, Selection, Propagation, and Planting

Importance of Climbers

• Efficient use of vertical space.
• Provide shade, privacy, and screening.
• Enhance walls, pergolas, fences, and arches.
• Flowering climbers add fragrance and colour.

Selection of Climbers

• Growth mechanism: twining, tendril-bearing, root climbers.
• Purpose: ornamental, shade, screening, covering walls.
• Flowering characteristics: seasonal vs. continuous.
• Examples: Bougainvillea, Thunbergia, Allamanda, Clerodendrum, Quisqualis.

Propagation

• Hardwood or semi-hardwood cuttings (Bougainvillea, Jasmine).
• Layering for slow-rooting species.
• Seeds for creepers with fast germination.

Planting

• Provide supports: trellises, pergolas, arches, walls, wires.
• Plant near structures but maintain 30–50 cm distance for root health.
• Regular pruning for controlled growth.

Annuals: Selection, Propagation, and Planting Scheme

Annuals complete their life cycle within a single season and provide vibrant colour to gardens.

Selection

• Season-specific varieties:
  • Winter annuals: Antirrhinum, Petunia, Pansy.
  • Summer annuals: Zinnia, Cosmos, Sunflower.
  • Rainy season annuals: Balsam, Portulaca.
• Height categories: dwarf, medium, tall.
• Purpose: bedding, borders, pots, hanging baskets.

Propagation

• Seed sowing in nursery beds or trays.
• Transplanting at 4–6 leaf stage.
• Direct sowing for hardy annuals like Sunflower and Balsam.

Planting Scheme

• Bedding: Large colourful patches arranged in geometric or free-form designs.
• Edging: Dwarf annuals such as Alyssum, Lobelia.
• Mixed Borders: Combination of annuals with shrubs and perennials.
• Hanging Baskets: Trailing annuals like Petunia and Nasturtium.

Other Garden Plants: Palms, Ferns, Grasses, Cacti and Succulents

Palms

• Provide vertical elegance and tropical appearance.
• Examples: Areca palm, Date palm, Fan palm, Bottle palm.
• Propagation: seeds, division of suckers.
• Used in avenues, courtyards, and indoor landscapes.

Ferns

• Shade-loving plants with delicate foliage.
• Examples: Nephrolepis, Adiantum, Pteris.
• Propagation: spores, rhizome division.

Ornamental Grasses

• Add texture, movement, and contrast.
• Examples: Fountain grass, Carex, Pampas grass.
• Low maintenance and suitable for borders and mass planting.

Cacti and Succulents

• Drought-tolerant plants ideal for rockeries and xeriscapes.
• Examples: Opuntia, Agave, Aloe, Echeveria.
• Propagation: leaf cuttings, offsets, and seeds.

Pot Plants: Selection, Arrangement, and Management

Pot plants enhance indoor and outdoor spaces and are easy to maintain.

Selection

• Based on light requirement: shade-loving, partial shade, or full sun.
• Growth habit: upright, bushy, trailing.
• Container size and material: clay, ceramic, plastic, metal.
• Indoor vs. outdoor suitability.

Arrangement

• Group plants of varying heights for visual layering.
• Use decorative pots to complement interiors.
• Place shade-loving plants in corners or verandas.
• Install hanging baskets for trailing species.

Management

• Regular watering according to plant needs.
• Use of well-drained potting mixture.
• Repotting annually or when roots overgrow.
• Fertilization using liquid or slow-release fertilizers.
• Pest and disease monitoring.
• Providing adequate sunlight and ventilation.

Conclusion

Understanding the characteristics, propagation methods, and planting schemes of ornamental trees, shrubs, climbers, annuals, and pot plants enables students to plan and develop aesthetically pleasing and functional garden landscapes. Integrating these plant groups enhances biodiversity, visual appeal, sustainability, and ecological balance in both small and large-scale garden settings.