Planting and Maintenance

Overview of Planting and Maintenace

• Preparing for Planting
• Planting Techniques
• Weeding
• Forking
• Watering and Soil Aeration
• Manuring
• Composting
• Mulching
• Shrub Pruning
• Plant problem management

Planting

Benefits of landscape planting

1) Physical Benefits

• Microclimate Enhancement - The trees provide shade, reduce surrounding temperature, reduce solar radiation and reflection. Plants help to modify wind by obstructing, guiding, deflecting and filtering airflow
• Air purification
• Noise reduction
• Erosion control

2) Visual Benefits

• Landscape Aesthetics - Provide a variety of color, form, texture and pattern in the landscape e.g bougainvilleas in the planters helps to beautify overhead bridge, Ficus pumila helps to soften hardscape, creeping onto walls of overhead bridge. 
• Soften architectural lines
• Screening or green buffer

3) Economic Benefits

• Landscape plants, particularly trees, add to the value of real estate
• Fruit trees, spices, herbs or medicinal plants are planted for their economic values and uses. 

4) Psychological Benefits

• Plants have positive influence on human behavior
• Hospital rehabilitation programs increasingly include plant propagation and gardening 
• Industry officials have found that attractive buildings and landscapes result in above average labour productivity, lower absenteeism, and easier recruitment of workers with hard-to--find skills.

Common category of plants

• Grasses
• Ground Cover
• Ferns
• Shrubs and Herbs
• Climbers
• Palms and Cycads
• Trees

Composting the Planting Design
The process of designing a garden can be simplified as such:

• Program development
• Site planning
• Designing concept plan

Program development

• Understand what you want in your garden
• Existing site conditions and problems
• Elements and functions of the garden
• Intended feeding or character of the design time and resources

Site planning

• Have a clear understanding of the site
• Carefully consider the functions and elements of the design to the site so as to minimize conflict e.g Playground should not be next to a road or carpark.
• Functional aspects of the garden

Concept design
Designer determines the suitable character or style preferred for the open spaces e.g

Different types of garden design:

• Formal Garden
• Tropical Garden
• Dry Garden
• Balinese Garden

Important Landscaping Considerations

• Composition
• Scale
• Balance
• Contrast/Harmony or complement
• Color
• Texture
• Shape
• Forms
• Drawing to scale

Choice of plants

• Choosing plants that are suitable for your garden is the first step towards ensuring a healthy and luxuriant garden. 
• The selection criteria consist of:
  
  • Functional requirement
  • Horticultural requirement
  • Maintenance requirement

Functional requirement
Things to consider at the planning stage:

• Growing Habit - upright/spreading or a climber etc
• Spread - The spread of a plant at maturity with correct spacings and avoid overcrowding
• Form - Plants have their own forms, which is an important consideration for design.
• Rate of growth
• Fucntion of the planting sites, be it in a garden, along roadside, park, landscape area or arboretum
• Aesthetic criteria - Color and texture of the foliage and flowers

Horticultural requirements

• Environmental analysis with the plant choices e.g Environmental preferences of the plants, is it a sun or shade plant
• Different horticultural requirement such as light condition, soil type, moisture, hardiness

Maintenance requirements
Maintenance requirement is considered in the design phase by assessing

• Maintenance frequency (pruning, fertilizing)
  Use low maintenance plants to avoid frequent topping, shearing and pruning to reach the desired effect. If the design requires a four-foot hedge, choose a plant that ultimately grows to four feet in height.
• Choose plants that grow to an appropriate size for the area planted.
  Envision the design in ten years, twenty years and fifty years.
• Project cost and maintenance cost
  The capabilities of the client and practicality issues
  No garden or landscape is maintenance free!

Nursery sourcing
Research on your plant choices to ensure that you can find them through the wholesale nursery trade. This means contacting nurseries to find out if they have the size and quantities you need.

Contract growing
Contractual agreement is made for a specific number of plants to be grown for a special project. eg. supply and planting of annuals along roadside during international events in Singapore.

Maintenance Practice

Overview of Maintenance Practice
Planting and installationn techniques
Forking, aeration and weeding
Pruning
Watering and Fertilizing
Mulching and composting
Plant problem management

Forking
The process of loosening the soil crust to introduce oxygen and nutrients to plants.

Benefits of forking

• To prevent soil compaction
• To enhance the development of roots
• To improve soil aeration and water drainage
• To incorporate fertilizers into the soil
• To help in weed control (loosen soil and remove weeds)

Tools for forking

• Garden fork
• Spike roller
• Hollow tine fork

Types of forking

• Total base forking
• Trench forking
• Semi-circular forking
• Spot forking
• Ring forking
• Spike forking

Effects of compaction on soil

• Decrease total pore spaces
• Poor soil water movement
• Poor gas exchange

Effects of compaction on plant growth

• Roots can only penetrate soil pores larger than itself
• Soil compaction will cause decrease in root penetration and elongation
• Roots cannot spread, which would restrict growth. If there is a drought, roots will die due to transpiration needs. 

Effects of waterlogged on plant growth
There are many reason why plant may come to be growing in waterlogged soil. It may be due to compaction panning preventing free drainage, or as a result of overwatering. When waterogged occurs, water occupy pore space, which would limit gas exchange and oxygen deficiency would occur immediately. Oxygen depletion leads to increase in carbon dioxide concentration. In the absence of oxygen, anaerobic respiration may occur, producing toxic alcohol as waste product. Plants may appear stunted. Retard growth in leaves, roots, height, cambial, reproduction.

Actions to avoid waterlogging

• Frequent forking; loosen soil crust
• Use of aeration (perforated) slabs in road sidetables, centre dividers, car parks. 
• Change to better soil-mix the soil with expanded clay, coco-peat etc materials that will holf water and have large pores.

Effects of waterlogged soil
Toxic compounds produced are such as sulphides, carbon dioxide, soluble Fe, Manganese. This may be accompanied by the production of hydrogen sulphide gas producing rotten egg smell. Topsoils waterlogged for long periods in warm conditions have a smell of bad eggs (sulphur cycle)

Aeration
The process of using a tool or machanized equipment to puncture the soil, forming holes
Producing spikes (spike aeration)
Remove 'cores' of soil from the ground
Improves drainage and reduces puddles formation

Weeding
Removal of unwanted plants in a landscape area as weeds would compete nutrients intake with landscape plants, affecting the growth. A weed is considered to be any plant growing where it is not wanted.

Weed control methods

• Preventative methods
• Control noxious weeds along roads to prevent their transport to uninfested areas.
• Use only clean healthy seeds for sowing
• Proper composting of manure
• Cleanliness of equipment

Manual/Mechanical methods

• Hand pulling
• Close planting
• Regular mowing
• Mulching
• Solarization
• Cultivation

Chemical methods

• Weedicides/herbicides are catagorized by the way they affect the plants and how they are applied. Broadly catagorized into:
• Selective vs Non-selective eedicides
• Contact vs Systemic 

Selective herbicides

• imply chemical that kill some plants but not others
• kill or stunt weeds in a germinating or growing plant without harming the plant beyond the point of recovery

Non-selctive herbicides

• Kill all plants when applied at adequate rate
• These herbicides are used in places where no plant growth is wanted

Contact herbicides

• Most effective against annual weeds, kill only the plant parts to which the chemicals are applied. These kill plant parts directly contacted by the herbicides. 
• Cause rapid weakening and disorganization of a plant cell membranes to the point where there is a loss of cell contents by leakage. 
• Effective against annual weeds

Systemic herbicides

• Chemicals are absorbed either by leaves, stems or roots and are then translocated within the plant system to tissues that may be remote from the point of application. 
• Their mode of action is generally to disrupt chemical processes critical to plant growth and nutrient. Effects may not be seen for a week or more after treatment.
• E.g 2,4-D, MCPA, Glyphosphates (round-up)

Biological methods

• Weed control methods making use of living organisms introduce animals

• parasites, predators and pathgens of weed
  e.g The mottled water hyacinth weevils from South America, that has been successfully introduced into Africa and Australia, feeds voraciously on the leaves of water hyacinth.