Amenity Horticulture Hort 253 L. Atuah (Ph.D)

Outline Amenity horticulture- what it is and its relevance Challenges in amenity horticulture and the way forward Plants in the landscape Plant use – functional and aesthetic Maintaining amenity plants Some plant disorders and their treatments

Amenity Horticulture – what it is and its relevance It can be referred to as landscape horticulture or environmental horticulture. The term landscape commonly refers to the appearance of the land, including its shapes, texture and colours. It also reflects the way in which their various components combine to create specific patterns and pictures that are distinctive to particular localities.

Amenity Horticulture – what it is and its relevance The landscape or the natural environment has gone through various modifications which are man made. Amenity horticulture therefore refers to the use of plants in the landscape to effect aesthetic patterns, enhancing comfort and pleasantness. The plants may also serve other functional purposes like checking erosion, screening etc.

Amenity Horticulture – what it is and its relevance Amenity horticulture is therefore applied in such a way that it reflects the set of priorities of the users of a particular environ. Multi-professional collaboration is required to produce the cohesion needed in our landscapes/environs. Name professionals that will be needed for such collaboration and briefly explain why?

Challenges in Amenity Horticulture General challenges: Vandalism, litter, poisonous plants, hideouts for ‘bad people’, timeliness in keeping maintenance schedule. Challenges peculiar to Ghana – name as many as you can think of.

Amenity horticulture in Ghana- The way forward Education Legislation More research on ornamental plants and the environment (implying provision of funds) Re-organising the department of Parks and Gardens Innovative ideas like an award for Ghana’s most beautiful suburb etc.

Plants in the landscape The plants in the landscape can be categorised. They may be either of the following; Trees Shrubs Herbaceous perennials Grasses and creeping plants/ground covers Climbers Bromeliads Ferns Cacti and succulents Water plants

Plants in the landscape Plantings in the landscape may either be formal or informal. Trees: The four main groupings of trees are namely, foliage trees, flowering trees, conifers and palms. Some examples are enlisted in later slides.

Foliage Trees Scientific name Common name Some characteristics Ficus benjamina Azadirachta indica Pithecellobium saman Michelia champaca   Ravenala madagascariensis Weeping fig Neem Rain Tree Champac Traveller’s Tree Weeping spreading tree Upright spreading tree Spreading tree Medium size erect and Pyramidal tree Erect fan shaped plant

Flowering Trees Scientific name Common name Some characteristics Cassia fistula Cassia nodosa Lagerstroemia speciosa Poinciana regia Plumeria alba Golden shower Pink shower tree Queen flower Flamboyante Frangipani, Forget-me-not Pendulous yellow flowers Pink flowers Showy purple flowers Large scarlet flowers White flowers

Conifers & Pines Scientific name Common name Some characteristics Araucaria heterophylla Araucaria bidwilli Cupressus Sp Thuja orientalis Casuarina equisetifolia Norfolk Island Pine Bunyan bunyan Cupressus Thuja Whistling pine Pyramidal evergreen Spiny evergreen Bushy and dense Dense busy pyramidal tree  Needle-like leaves

Palms Scientific name Common name Some characteristics Roystonea regia   Cocos nucifera Caryota urens Washingtonia filifera Royal palm Coconut palm Toddy Palm There are both tall and dwarf varieties Tall and dwarf varieties Erect tree with spiral leaves

Shrubs A shrub may be distinguished from a tree by the fact that it is bushy and mostly multi- stemmed (i.e. woody, a plant smaller than a tree and with several woody stems). Shrubs are usually divided into two groups - flowering and foliage. They are grown in the landscape individually as specimen plants or in groups for shelter belt, hedges, bedding plants or in shrubberies.

Examples of shrubs Flowering shrub: Scientific name Common name Some characteristics Acalypha hispida Allamanda cathartica Bougainvillea glabra Hibiscus rosa-sinensis Ixora duffi Monkey tail/red fingers Allamanda Purple bougainvillea Hibiscus/Rose of China  Double red ixora Slender long flowers Yellow trumpet shape flowers Has thorns and is a climber Different kinds exists; red, yellow, pink flowers Large heads of crimson flowers

Foliage shrubs Scientific name Common name Some characteristics Acalypha willinckii Acalypha wilkesiana Breynia nivosa   Pseuderanthemum atropurpureum Polyscias spp. Variegated acalypha Acalypha tricolor Ice plant/snow plant Purple eranthemum Panax Has heart-shaped leaves Brown leaves blotched with red Terminal leaves are variegated white Has purple leaves Several kinds exist

Herbaceous perennial These are perennial herbaceous plants which are either grown for their flowers or foliage. They include bulbous, tuberous and rhizomatous plants. Scientific name Common name Some characteristics Anthurium andreanum Canna spp   Gerbera jamesonii Heliconia bihai Pentas parviflora Anthurium lily Canna lily Barberton daisy Lobster claw Red Pentas/flaming Katie Bears large waxy scarlet flower Numerous varieties with different colours When well irrigated it continue to flower throughout the year Bears yellow bracts Cannot withstand drought

Climbers Climbing plants consist of both perennial woody, herbaceous plants and annuals. These plants have various devices for climbing which include tendrils, twining stem, root-like holdfasts and drooping or rumbling over a support. Since most climbing plants grow vigorously and consequently carry a lot of vegetation, stakes or supports used must be sufficiently strong.

Climbers Scientific name Common name Some characteristics Monstera deliciosa Scindapsus aureus Thunbergia alata Ficus pumila   Petrea volubilis Ceriman Scindapsus Black-eyed Susan Creeping fig Purple wreath Has perforated leaves Quick growing Yellow funnel shaped flowers Very useful for covering bare walls Has brittle papery leaves

Grasses and ground covers Turf grasses perform the function of ground cover plants. They are grown mainly in lawns, playing fields etc. Ground cover plants are very useful on slopes, irregular surfaces and in rocky areas where mowing of grass is not possible. Scientific name Common name Some characteristics Chrysopogon aciculatus   Axonopus compressus Cynodon dactylon Setcreasea purpurea Tribulus cistoides Love grass/Tafo grass Carpet grass Bermuda grass Purple heart Tribulus Grows in full sun and semi-shade full sun and semi-shade Does not thrive under shade Violet flowers open in the morning closes by afternoon Very showy yellow flowers

Ferns Ferns belong to a group of plants which produce pores instead of flowers and seeds. The spores are found on the fronds, usually beneath. Suitable conditions for growth and development; damp semi-shaded conditions with protection from wind. Scientific name Common name Some characteristics Adiantum capillus-veneris Nephrolepis exaltata Asparagus plumosus   Asparagus sprengeri Maidenhair fern Sword fern Asparagus fern Cannot recover once wilted Fronds are erect and stiff Fern-like with need-like branchlets Can grow both in full sun and semi-shade

Cacti and Succulents These plants can withstand a considerable amount of neglect. This is possible because of their resistance to drought, dry, hot and difficult conditions. Cacti has adaptive features to cut down on loss of water through transpiration. These are thickened stems and spines which are modified leaves. The fleshy nature of succulents allow for maximum retention of moisture. Transpiration is further reduced by a thin wax coating or woolly hairs plant parts.

Cacti and succulents Scientific name Common name Some characteristics Agave americana   Euphorbia splendens Kalanchoe blossfeldiana Rhoeo discolor Sansevieria trifasciata laurentii Century plant Christ’s Thorn  Flaming Katy Lady-in-boat/Moses in the cradle Mother-in-law tongue Spreading plant with a large rosette of thick and stiff leaves. Sparsely foliaged with spiny stem. Erect house plant bears clusters of scarlet flowers. Succulent leaves which are glossy purple beneath and green above. Erect cylindrical pointed leaves.

Water plants Three general groups of water plants; Those which grow entirely beneath water, those which have their roots and stem beneath water surface, those with their roots growing in water and stems and leave above water surface. Scientific name Common name Some characteristics Nymphaea spp   Pistia stratiotes Thalia dealbata Water lilies Water lettuce Water Canna Waxy leaf surface with closely set minute hairs Floating plant preferring shallow waters Floating and bears small dull violet flowers

Plant use Avenue plants – Trees with clear trunks (allowing for people to walk under) is ideal. The trees must have aggressive root systems, should not have brittle branches and not be messy (by way of leaf and seed drop). The roots must have deep root system to afford good anchorage. Specimen plants – Plants with unique characteristics. They should be sufficiently attractive to stand alone. Hedge – Plants (especially shrubs) grown with close spacing and trained in such a way to make a barrier or mark a boundary.

House plants – they are plants which can be expected to live permanently under room conditions.

Plant Use – functional and aesthetics Trees Avenue plantings Provision of shade Specimen Noise control Pollution control Wind breaks

Plant use Shrubs: Hedge Median planting to reduce headlamp glares Potted plant Bedding plant Border plant

Herbaceous perennial Beds Borders Establishing an avenue: In avenue planting there should be a layout and design and the following should be considered: Length If an avenue leads from one definite point to another, its length is automatically defined. In other cases, the length should be decided in the light of certain guiding factors including the following:

If too long, an avenue tends to become monotonous. If very long, care must be taken to ensure that it is not too narrow, in which case it will tend to shrink to vanishing point before the end of it is seen. If a very long avenue is made too wide, in order to avoid the last pitfall (shrinkage), the trees of which it is composed will appear to be dwarfed. Avenues should not normally be more than one-half to three-quarters of a mile in length if the above points are to be avoided.

The table below can be used as a guide It is difficult to lay down the exact width of an avenue. The habit of the species planted: large crown trees need more space than those with narrow crown. The table below can be used as a guide The length of the avenue: long avenues should be rather wider than those of shorter length. Length of avenue (m) Width of avenue (m) 91 91-182 182-365 365-548 548-640 640-751 9 12 15 18 21 24

The number of rows of trees of which the avenue is composed: an avenue of two single rows should be rather narrower than one with two double rows. City conditions are often unfavourable for tree growth and species must be selected which can tolerate air pollution, dry conditions, glare from pavements etc. Suitable trees should be planted far enough from the kerb to allow them to spread without too much pruning. They should be kept clear of overhead wires and underground services.

Discuss how a tree can be planted (Steps involved) Trees in car parks The task of accommodating trees within a car park is not always straightforward as it may seem. The challenge on site a car park; are usually hard surface, dry conditions, lack of air and the intensity of the light which is thrown up from the ground to the tree. This can result in leaf scorch and abnormal transpiration rate. Vehicles may damage trees by reversing into them and tree roots can be poisoned if fuel run-off gets into the water supply.

To avoid the afore mentioned hazards it is usually suggested trees in car parks be planted between raised kerbs or in elevated boxes. Hazard fencing at bumper height can go some way to meeting practicalities but the careful siting of trees in relation to the overall car park design gives the best solution. In tree selection, the tree should be able to withstand pollution.

Hedges Essentials required are a shovel, rope/string, tape measure, stakes/pegs, compost, spray paint (optional). If a really dense and bushy hedge from ground upwards, it is advisable to plant young small plants. The result of using large plants can often be that the hedge is rather gappy at the base. Soil preparation: Prepare the ground by digging over a strip 60-90cm wide and one spade blade deep. Remove all weeds if a weedkiller has not been used before hand.

Hedges Add organic matter such as garden compost, spread it over the soil and mix in top 25 cm of soil with a fork. You may also mix in a general purpose fertilizer. Planting Planting distances vary from 30-60 cm, depending on the plants’ final size, the size of hedge required and plant vigour. For hedges thicker than 90 plant a staggered double row 45 cm apart with plants 90 cm apart. Trim back damaged roots to healthy growth with a sharp knife.

Hedges Spread out the roots, ensuring the planting depth is correct (note that the previous soil mark on the stem indicates how deeply the plants were grown in the nursery). Work soil between the roots, firm plants in so that soil is in close contact with the roots. Then water. Mulch to a depth of 7.5cm after planting to prevent weeds. Why will one plant a hedge? What kind of plants are recommended for median planting?

Planting beds and borders These are plants which are grown in beds and borders to give color to a landscape environment. They include annuals, biennials, herbaceous perennials, ferns, fern-like plants, orchids, cacti and succulents and shrubs. Beds stand as an island of selected flowering plants. They could take any shape especially geometric shapes; square, oval etc. If the bed is sited in a lawn you will have to be careful your chosen shape will not hamper mowing of the grass. If you plan a large bed you will have to make provision for access in order to facilitate maintenance.

Beds and Borders Beds should be viewable from different angles. Borders- They are planted against a wall or hedge. The plants in a border will therefore be affected by shadow from the wall, possible reduced impact of rain. Take into consideration the backdrop when planning the colour scheme of the border. Be aware also of the fact that maintenance works on the wall or hedge can affect the plantings in the border. How can you establish a bed; square and circular shape?

Lawn (Turf) establishment Lawn: A smooth layer of land covered with turf. Turf: A ground cover of grass which is kept mown and which will stand a reasonable amount of traffic. Verge: A narrow strip of turf between beds, paths, walls etc. Preparations involved: Soil preparation is essential to ensure there is quick establishment of uniform turf. The goal is to create a fertile homogeneous root zone with acceptable infiltration, aeration and drainage.

Lawn (turf) establishment Depending upon the scope of the project advance planning may be of relatively little or of very great importance. In general turf can be established from seeds or vegetatively. This could be by sodding, plugging, stolonizing and sprigging. Sodding: The process of installing mature turf in large or small sheets, as opposed to spreading seed or sprigs over a prepared area of bare soil. Sod is established turf that is harvested with roots and soil attached and transplanted from its place of origin and installed like carpeting to grow in another place.

Sodding is the most expensive method of turf establishment but produces an established turf within hours rather than weeks or months. The only maintenance required during the early weeks of establishment is daily watering when there are no rains. Sod is bought from a farm in the form of rectangular pieces or as long rolled strips. Stolonizing: Every bud on a stolon can potentially become a new plant. Many tropical turf-grass do not produce viable seeds. Stolonizing is therefore one of the methods for establishment of turf.

Sprigging: The process of vegetatively establishing turf grass by spreading rhizomes or stolon over a prepared seed bed and pressing them into the soil. It is a modification of stolonizing. It involves placing stolons in narrows spaced 15 to 20cm apart and manually covered. 15 to 20% of the stolon should extend above the surface. The advantage over stolonizing is less risk of desiccation. The disadvantage is high labour cost. Plugging: Small (5 to 10 cm) diameter pieces of sod are transplanted into a prepared area 15 to 35 cm apart.

Site preparation This is the same irrespective of the method adapted for establishment. Steps: Debris removal Elimination of existing vegetation and preventive weed control. An ideal herbicide/weedicide translocates through and kills the entire plant without leaving a harmful residue in the soil.

Glyphosate known commonly as Kleenup or Roundup will kill both annual and perennial weeds. Weeds also can be removed by digging. Levelling – This involves changing the slope of the area into an even gradient. This can be adequately worked on from the subsoil before spreading the top soil.

Soil amending – Depending on the soil condition of the topsoil soil amending may be needed to improve drainage, fertility or pH. Surface preparation – The surface on which the seed is to be sown should be free of clods and form a tilth. A light raking will remove remaining clods and provide the final surface.

Information on seed germination rate and purity must be noted. Seed rate – Generally package directions are the best source of information on seeding rate.

For heavy seeding may be done but it have some disadvantages For heavy seeding may be done but it have some disadvantages. There will be quick results but it will be under over crowded conditions and weaker seedlings will be weeded out by stronger ones which will eventually form a stand of plants equal to that which would have been formed naturally at a lower rate. Seeding Techniques: For large areas Mechanical methods should be adopted.

Maintaining amenity plants Trees Shrubs Grasses This may involve the following: Pruning Watering Mulching Shading Removal of Competition/Weed Control. Staking Fertilization

Maintaining amenity plants The general principles for pruning trees and shrubs will be considered. Pruning is the removal of plant parts on purpose to enhance growth and maintain the usefulness of the plant. Pruning tools: Examples of hand pruners – Pruning saw, hedge shears, hand pruners, lopping shears. Purpose for pruning: Size control Health improvement Appearance improvement

Pruning young trees: This implies pruning at transplanting and within the first few years after transplanting. (why may pruning be a requirement at transplanting) During the first few years of transplanting the plant develops the main branches which will form the support structure for the foliage. Pruning directs the growth of those branches in order to create a strong tree. What is a strong tree?

Look out at the early stages of plant development for double leaders and remove them. Most trees have a ‘central leader’ but a occasionally two leaders develop causing a fork. If the weaker of the two lead branches is not removed, it poses a potential cause for damaging of the tree trunk with time. As each leader increases in diameter, it exerts pressure against the other at the base and this can cause eventual splitting.

Selection of scaffold branching. The lateral branches along the main stem is referred to as scaffold branches. It is best to control the extent of branches in the initial stages of development of a tree. It is best if they are widely spaced and evenly along the trunk. Pruning mature trees: A tree that was properly pruned when young should need little pruning when mature. Three-cut pruning method is adopted for removing large branches/limb

Mature branches are usually heavy and easily break and rip off tree back if being sawed off by one cut. The three-cut pruning: 1st cut is made under the branch about 30 cm away from the trunk and goes halfway through the branch. The 2nd cut is made about 8 cm away from the 1st cut from the top of the branch. This is cut through. The 3rd cut removes the stub.

Note Some trees may naturally not have a central leader and it will be a mistake to prune to have one. Pruning of such trees may involve only desuckering and removal of crossing and inward-growing branches. Pruning shrubs:- This involves; Thinning Heading back Renewal Pruning

Shrubs are multi-stemmed coming out from the basal portions of the plant. With time as they grow by increasing in height and number of stems there will be the need to thin. This is because as the older stems age and lengthen, they have the tendency to shade out the bottom foliage. This results in the shrub becoming bare at the base. Thinning consists of removing the oldest stems at ground level. This shortens the shrub and encourages new shoots to grow from the roots and refoliate the bottom.

Heading back:- This consist of cutting twigs or small branches to just before/above an outward pointing bud. It encourages new growth to develop outward and eliminate crossing branches.

Heading Back

Renewal pruning Used to rejuvenate and shorten over grown shrubs. Where branches are cut back they are reduced to stubs 5 - 8 cm long. Renewal pruning involves thinning techniques as well as cutting back. It a drastic measure which will make the plant unsightly in the first two years.

Pruning hedges What is a hedge? (Recall) Hedges can be classified as formal and natural (informal). Pruning of a natural hedge/shelter belt is same as pruning a shrub i.e. thinning and heading back. Formal hedges require frequent pruning to maintain a neat appearance. What is important is the selection of the correct hedge shape.

Hedge shapes

Mowing Sound mowing is perhaps the single most important factor contributing to the attractiveness and longevity of any turf-grass area. The height of cut is important. The height to which a given grass can be mowed is directly related to its ability to produce enough leaves and to keep up with production of carbohydrates. Some creeping grasses with fine leaves, such as cynodon and zoysia, when properly fertilised and watered, are able to produce adequate leaf surface at very low mowing heights.

It has been determined that removal of more than one-third of total leaf area results in severe physiological shock. With this in mind, only the growth rate will determine the mowing frequency. Mowing equipment: There are a number of mower types. The most accurate are the reel mowers (cylinder mowers), rotary mowers are intermediate and sickle-bar mowers are the least.

The proper choice of mowing equipment depends on the type of grass and the conditions of usage and maintenance. For high-quality sport or recreational areas, reel mowers are recommended for cutting. They provide a clean even cut and leave the turf looking the most attractive. Rotary mower should be used where perfect appearance is not necessary. And where ease of operation, maintenance and price are of significant concern.

Sickle bar mowers are the simplest and roughest Sickle bar mowers are the simplest and roughest. They are used mainly across road side and other areas where turf appearance is of secondary concern. Reel mowers: A reel mower consists of a horizontal rotating cylinder, the reel, with attached blade and stationary bed knife, which is parallel to the ground. The reel usually bears between 3 and 7 blades, and the width of the mower usually ranges from 50 to 80 cm depending on the model.

Rotary mowers: The blade of a rotary mower is usually a single sharpened metal bar suspended parallel to the ground at its centre point. It spins in a horizontal plane, striking and severing vertically growing leaf blades. They do not provide an even cut and they cause certain amount of mutilation at the point of impact.

Mower operations Mowing should be done only when the grass is dry. This is because the mower is less likely to clog with soggy clippings. Secondly grass blades are more susceptible to disease invasion through the cut surface when wet. It is important to sharpen mower blades often. A clean cut minimises the damaged area and reduces tip browning of the blades. It also decreases moisture loss and eliminates bruised blades which are a site for disease entry.

Some plant disorders A key to determining the kind of disorder is to know the cause of it. The cause may be attributed to either a parasitic organism or an environmental condition. Examples of parasites: Rodents, insects and microorganisms such as bacteria and fungi. Examples of environmental conditions: Heat, drought, pollution etc.

There are some disorders that may be as a result of deficiencies or toxicities. This may result in manifest the manifestation of certain symptoms depending on the nutrient element that is lacking or in toxic levels. Note that symptoms are first seen in the oldest leaves when the nutrient element can be easily moved about the plant. In deficiency, the small supply is shunted to areas of growth in an attempt by the plant to complete the life cycle. Symptoms are first seen in the youngest leaves when the element in poor supply is held firmly where it was first used.

Deficiencies may often result in stunted growth and off-colour leaves. Other causes of stunted growth may be; Waterlogging, salinity, drought, disease eg root rot, insects, viruses. Too much or too little light Wrong day-length Toxins in medium

Problem Symptoms Pests Symptoms Caterpillars Parts of leaves eaten away. Borers Borrow into stems, underneath part of leaf eaten away whiles top remains untouched. Leaf miners Scribble-like patterns on leaves. Grasshoppers Large portions of leaves eaten. Aphids Disfigurement of leaves and buds. Mealy bugs Raised spots or dots on leaves, leaves drop. Nematodes Yellowing, general lack of vigour, roots knotted. Death of irregular sections of leaves and spotting.

a. Fungi caused: Wilt Entire or a section of plant wilts and cannot recover even after watering. Leaf spot Spots (concentric rings with dark centre) appear on foliage and sometimes on stems and flowers spreading to cover all other parts. Spots reduce photosynthetic area of leaves and plant may dies. Blight Quick wilting and death of young and growing tissues such as flowers and twig. Rust Reddish-brown spots on foliage and stems.

Virus caused: Curly top Twisting, distorted foliage. Mosaic Mottled light and dark areas on foliage.

Plant (disorder) disease control If the plant is diseased, the control may be both cultural and chemical and understanding of both is essential to restoring and maintaining plant health. Cultural control: Watering Sanitation Pruning Roguing Crop Rotation Resistant Varieties and species