Part I. General Principles
1. Comply with the nature and functional requirements of landscape green space

When designing garden planting, we must first start from the nature and main functions of the garden green space. Garden green space has many functions, and a specific green space always has its specific main function.

2. Consider the needs of garden art

1. Coordination of the overall artistic layout

Regular garden plants are mostly planted in pairs or rows, while natural gardens use asymmetrical natural arrangements to give full play to the natural posture of plant materials. Different forms of planting are used according to the local environment and the requirements of the overall layout. For example, regular planting is generally used near gates, main roads, plastic squares, and large buildings, while natural planting is used near natural landscapes, lawns, and asymmetrical small buildings.

As shown in the picture on the right: Plants planted in different locations have different shapes and sizes, which can create a harmonious and colorful landscape.

2. Consider the changing scenery of the four seasons

The scenery of garden plants changes with the seasons. They can be divided into sections and sections so that each section or section highlights a seasonal plant landscape theme, seeking changes in unity. In key areas where tourists gather in all seasons, there should be scenery to enjoy in all seasons. Even areas dominated by the landscape of one season should be dotted with plants of other seasons, otherwise it will appear extremely monotonous after one season.

3. Comprehensively consider the effects of plants on appearance, color, smell, and sound

(IV) Plant configuration should be based on the overall perspective

Pay attention to the density and contour lines of the configuration on the plane, pay attention to the crown line in the vertical direction, and organize the perspective line in the woods. Pay attention to the landscape level of plants and the viewing effect from a distance. When viewing from a distance, you should often look at the overall and large-scale effects, such as large pieces of autumn leaves, so that you can appreciate the shape of individual trees, flowers, fruits, leaves, etc. More importantly, you should consider the configuration of the garden planting method, and avoid nursery-style planting. When configuring plants, you must handle the relationship with buildings, mountains, water, and roads. When selecting individual plants, you should also look at the overall picture first, such as body shape, height, size, and outline, followed by leaves, branches, flowers, and fruits.

3. Choose suitable plant species to meet plant ecological requirements

Plant species should be selected according to the functions and artistic requirements of green space. For example, while street trees meet the main function of shading, they should also be tall, easy to survive, fast growing, adaptable to urban environment, resistant to pruning, and resistant to smoke and dust. Hedges should be densely foliaged, resistant to pruning, and able to form a barrier. Plants planted on the mountain should be drought-resistant and set off the mountain scenery. Waterside plants should be resistant to moisture and coordinated with the water scenery. In memorial gardens, some tree species that symbolize the memorial object and the favorite tree species of the memorialized person can be planted. To meet the ecological requirements of plants and enable them to grow normally, one is to adapt to local conditions and plant trees that are suitable for the land, so that the ecological habits of the planted plants and the ecological conditions of the planting site are basically unified. On the other hand, it is necessary to create suitable ecological conditions for the normal growth of plants. The selection of plants should be mainly local native plants, and excellent foreign plant species that have been successfully introduced and domesticated can also be used, or foreign plants that can create the required ecological conditions.

4. Planting density and matching

Whether the density of tree planting is appropriate directly affects the performance of greening functions. From a long-term perspective, the planting distance should be determined according to the crown size of mature trees. If you want to achieve a good greening effect in the short term, the planting distance can be closer. Generally, the method of appropriately configuring fast-growing and slow-growing trees is often used to solve the problem of transition from the long term to the short term. However, the tree species must be appropriately matched to meet the ecological requirements of various trees, otherwise the ideal effect cannot be achieved.

In terms of tree configuration, we should also consider the combination of fast-growing trees and slow-growing trees; evergreen trees and deciduous trees; trees and shrubs; foliage trees and flowering trees. In terms of plant configuration, we should also determine the appropriate ratio between trees, flowers and plants according to different purposes and specific conditions. For example, the proportion of evergreen trees in memorial parks can be higher. When planting trees, we should also pay attention to harmony, and make gradual transitions to avoid abruptness. Planting design should consider retaining and utilizing existing trees, especially precious ancient trees, and can be planted with plants based on the existing trees.

In order to better reflect the greening effect and shorten the time of landscape formation, the method of transplanting ancient trees is often used in some major scenic spots.

Part II. Planting Design of Trees and Shrubs

1. Usage characteristics of trees and shrubs

Trees and shrubs are upright woody plants. They play a significant role in the comprehensive functions of landscaping and occupy a dominant position. They account for a large proportion of garden green spaces and are the most basic and important components of garden plant planting, and are the skeleton of landscaping.

The crown of the tree is tall and has a long lifespan. The crown occupies a large space, while the trunk occupies a small space, so it does not hinder the activities of tourists under the tree. The shape and posture of the tree are varied, and the distribution of branches and leaves is relatively transparent. It has a significant effect in improving the microclimate and environmental sanitation, especially with a good shading effect. In terms of landscaping, the trees are also diverse and colorful, from lush forests, beautiful trees, to isolated trees of various shapes and forms, all of which can form beautiful landscapes. In the garden, the tree can be the main scenery, form space and separate space, and can also play the role of increasing the spatial level and blocking the line of sight. Because the tree has a tall crown and a huge root system, it is generally required that the planting site has a larger space and deeper soil.

The crown of shrubs is short, mostly in a clumping shape, and has a short lifespan. Although the crown occupies a small space, it is right in the range of people's activities. It has a greater impact on human activities than trees. The branches and leaves are dense and full, often with bright and beautiful flowers and fruits, and there are many changes in shape and posture. They play a significant role in preventing dust, wind and sand, slope protection, and preventing soil erosion. In terms of landscaping, they can increase the changes in the height of trees, serve as a foil for trees, and can also highlight the effects of shrubs in flowers, fruits, and leaves. Shrubs can also be used to organize and separate smaller spaces and block lower sightlines. Shrubs, especially shade-tolerant shrubs, work together with large trees, small trees, and ground cover plants to become an important part of the main greening. Because shrubs have small crowns and limited root systems, they do not require much space for the planting site, and the soil layer should not be very thick.

Types of tree and shrub planting

1. Solitary Planting

Solitary planting refers to the isolated planting type of trees. This tree is also called an isolated tree. Sometimes under certain conditions, two or three trees can be planted closely to form a unit. But they must be of the same species, with a spacing of no more than 1.5 meters. From a distance, they look the same as single trees. No shrubs are allowed under isolated trees. The main function of isolated trees is to meet the needs of composition art. They serve as the main scenery of local open areas, and of course they can also provide shade. Isolated trees as the main scenery are used to reflect the full growth and development of individual plants in nature. They should be tall, luxuriant, and magnificent in appearance.

Isolated trees should be selected if they meet the following basic conditions:

1. The plant has a beautiful and large shape, dense branches and leaves, a wide crown, or other trees with special ornamental value;

2. They should be strong and long-lived, and able to withstand major natural disasters. It is advisable to select local native tree species that have been tested for a long time;

3. The trees do not contain toxins, and do not have polluting flowers and fruits that are easy to fall off, so as not to harm tourists or hinder their activities.

Although isolated trees account for a small proportion of trees planted in gardens, they play a very important role. The location for planting isolated trees should be relatively open, with not only sufficient growth space, but also a relatively suitable viewing distance and viewing point. It is best to have a background with simple and richly varied colors such as the sky, water, and grassland as a background to highlight the characteristics of the isolated trees in terms of shape, posture, and color. The location of isolated trees depends mainly on the overall unity with the surrounding environment. They can be planted in open grasslands, rivers, and lakes, or on highlands and hills. They can also be planted on the edge of the square in front of the park, as well as in the courtyards composed of garden buildings. In natural gardens, isolated trees can be used as intersection trees and induction trees to be planted at the turning points of garden roads or rivers, at the entrances of rockery steps, and at the entrances of local gardens to guide visitors into another scenic area. As part of the garden composition, isolated trees are not isolated and must complement the surrounding environment. Isolated trees in landscape gardens must be in harmony with the rocks that reveal strangeness, and the tree posture should be winding and ancient.

(II) Planting

Pair planting refers to the use of two trees in a symmetrical or balanced planting method according to a certain axial relationship. It is mainly used to emphasize the entrances of parks, buildings, roads, and squares. It is combined with shade and rest, and is used as a configuration in spatial composition.

In regular planting, trees of the same species and the same specifications are arranged symmetrically along the central axis of the main landscape. The line connecting the two trees is perpendicular to the axis and is equally divided by the axis. In regular planting, tree species with neat crowns are generally used. In natural planting, the planting is asymmetrical, but the left and right are balanced. The entrances of natural gardens, bridgeheads, both sides of the stone steps, both sides of the river entrances, the entrances of closed spaces, and the doorways of buildings all require natural entrance planting and induced planting. Natural planting is to achieve a balanced relationship with the central axis of the main landscape as the fulcrum. The trees distributed on both sides of the axis in the composition must be of the same species, but their sizes and postures must be different. The dynamics must be concentrated on the central axis. The vertical distance from the central axis is that large trees should be close and small trees should be far away. The planting points of the two trees are connected in a straight line and must not intersect at right angles with the central axis.

Generally, the distance between tall trees and building walls should be at least 5 meters, while the distance between small trees and shrubs can be reduced appropriately (at least 2 meters).

(III) Row planting

Row planting refers to the planting of trees and shrubs in rows with a certain spacing between rows, or with varying spacing within rows. The landscape formed by row planting is relatively neat, simple, and imposing. Row planting is the most commonly used basic planting form in regular gardens and green spaces. It can also be used to arrange relatively shaped parts in natural green spaces. Row planting has the advantages of being easy to construct and manage. Row planting is mostly used in areas with many buildings, roads, and underground pipelines. Row planting combined with roads can create a sandwich effect.

For row planting, it is advisable to select tree species with relatively uniform crown shapes, such as round, oval, obovate, tower-shaped, cylindrical, etc., rather than tree species with sparse branches and leaves and irregular crowns. The row spacing depends on the characteristics of the tree species, the specifications of the seedlings and the main purpose of the garden, such as landscape, activity venues, etc.

Generally, the height for trees is 3-8 meters, and for shrubs it is 1-5 meters.

There are two forms of row planting: equal rows and equal spacing, and equal rows and unequal spacing.

(IV) Cluster planting

Cluster planting is usually a type of planting composed of two to more than ten trees or shrubs. The ground where the cluster is arranged can be natural vegetation or grassland, grass and flower land, or it can be configured with rocks or terraces. Clusters are a type of planting that is emphasized in gardens and green spaces. It mainly reflects the comprehensive image of the beauty of the group of trees, but this image of group beauty is reflected through the combination of individuals. There is a unified connection between them and their own changes, which contrast and set off each other. The conditions for selecting individual trees to form a cluster are similar to those for solitary trees. Trees with special value in terms of shade, tree posture, color, fragrance, etc. must be selected.

Bushes can be divided into two categories: pure bushes and mixed bushes. Bushes that provide shade are best planted in the form of pure bushes, generally without shrubs or with a small number of shrubs, and usually tall trees with open crowns are suitable. Bushes used as the main scenery, induction, and background in composition art are mostly mixed bushes of trees and shrubs.

When the bushes are used as the main scenery, it is advisable to use mixed coniferous and broad-leaved bushes, which have a particularly good viewing effect. They can be placed in the center of the lawn, by the water, by the river, on the island or on the hill as the focus of the main scenery. In classical landscape gardens, bushes and rocks are often set in front of the white wall, in the corridor or in the corner of the house, forming a small tree and stone scene with a certain theme. Bushes used as guides are mostly arranged at the entrance, road fork and curved road parts, fixing the scenic tour road into a curve, guiding tourists to appreciate the rich and colorful garden scenery according to the designed route. In addition, they can also be used as a sign of the divergence of the path or to cover the foreground of the path, so as to achieve the effect of turning around and turning to another scene. Bush design must be based on local natural conditions and the overall design intention. The tree species used are few but must be selected accurately. The biological characteristics of individual plants and the mutual influence between individuals must be fully understood, so that the plants can obtain suitable conditions in terms of growth space, light, ventilation, temperature, humidity and root growth and development. Only in this way can the stability of the bushes be maintained and the ideal effect can be achieved.

The planting arrangements of clusters include: two-tree clusters, three-tree clusters, four-tree clusters, and five-tree clusters.

(V) Group planting

The number of individual trees that make up a group planting is generally more than 20-30. The main expression of a tree group is the beauty of the group. Like isolated trees and bushes, a tree group is one of the main scenes in the composition. Therefore, the tree group should be arranged in an open space with sufficient distance, such as a large lawn near the edge of the forest, a wide open space in the forest, a small island in the water, a wide water surface on the waterside, on a hillside, on a mound, etc. In front of the main facade of the tree group, at least four times the height of the tree group and one and a half times the width of the tree group, an open space should be left for visitors to appreciate.

The scale of the planting group should not be too large. In terms of composition, there should be open space on all sides. The composition of the tree group and each tree should play a certain role in the appearance of the group. The best way to combine the tree group is to adopt a closed and layered combination. Visitors are usually not allowed to enter the tree group, and it is not convenient for visitors to enter, so it is not conducive to providing shade and rest.

Tree groups can be divided into two categories: simple tree groups and mixed tree groups. Simple tree groups are composed of one type of tree, and perennial flowers can be used as ground cover plants. The main form of tree groups is mixed tree species. Mixed tree species groups are divided into five parts, namely, tree layer, sub-tree layer, large shrub layer, small shrub layer and perennial herbaceous vegetation. Each layer must be exposed, and the exposed part should be the part with outstanding ornamental characteristics of the plant. The tree species selected for the tree layer should have a particularly rich crown posture to make the skyline of the entire tree group rich in changes. The tree species selected for the sub-tree layer should preferably be luxuriant in flowering or have beautiful leaf color. Shrubs should be dominated by flowers and trees, and herbaceous cover plants should be dominated by perennial wild flowers. The soil surface under the tree group should not be exposed. The basic principle of tree group combination is that the highly lighted tree layer should be distributed in the center, sub-trees on the periphery, and large shrubs and small shrubs on the outer edge.

The planting distance of plants in the tree group should vary in density to form an unequal-sided triangle. Avoid planting in rows, rows or strips. Evergreen, deciduous, foliage and flowering trees should be planted in multiple layers and a combination of small-block and point-like mixing.

The appearance of the tree group should be undulating and varied, and attention should be paid to the seasonal changes and aesthetics of the four seasons.

(VI) Forest belt

Forest belts are widely used in gardens. They can block sight lines and separate garden spaces. They can be used as backgrounds, provide shade, and prevent wind, dust, and noise. Natural forest belts are belt-shaped tree groups, usually with a short axis of 1 and a long axis of 4 or more.

In a natural forest belt, trees cannot be planted in rows, and the distances between trees must be unequal. The skyline must fluctuate and the outer edge must be tortuous. The forest belt is also composed of trees, sub-trees, large shrubs, small shrubs, and perennial flowers.

The forest belt belongs to the composition of continuous scenery. The appreciation of the composition evolves as visitors move forward. Therefore, the forest belt composition should have a main tone, a keynote and a matching tone, and should have changes and rhythms. The main tone should change with the seasons. When the forest belts are distributed on both sides of the river and the road, it should become a complex composition. The left and right forest belts do not require symmetry, but the corresponding effect should be considered.

Forest belts can be pure forests or mixed forests, depending on their functions and effects. Mixed planting of trees and shrubs, deciduous and evergreen trees can also play a good role in dust prevention and sound insulation in the function of forest belts. The tree configuration of the shelterbelt can be selected and matched according to requirements, and the planting form is in rows.

7. Forest planting

Planting trees and shrubs in large numbers in patches or blocks to form woodlands or forest landscapes is called forest planting or forests. Forest planting is mostly used in large-scale park quiet areas, scenic tourist areas, or sanitary protection forest belts in rest and convalescent areas. Forests can be divided into dense forests and sparse forests. The canopy density of dense forests is 70-100%, and the canopy density of sparse forests is 40-70%. Both dense forests and sparse forests have pure forests and mixed forests. Dense forests and pure forests should use the most ornamental and strong local tree species. Dense and mixed forests have a multi-layer structure, such as a forest belt structure. Large-scale mixed dense forests are mostly mixed in sheets or strips, and small-scale mixed dense forests are mostly mixed in small sheets or dots. Evergreen trees are mixed with deciduous trees. The planting density of dense forests is maintained at a spacing of 2-3 meters between rows.

Sparse forests are often combined with grasslands to form "sparse forest grasslands", which can provide shade in summer and sunshine in winter. The lawns and open spaces are used for rest and activities. The scenery in the forest is varied and is deeply loved by tourists. The tree species in sparse forests should have high ornamental value, grow strong, have sparse and open tree crowns, and have beautiful scenery in all seasons.

8. Hedges and Green Walls

Any regular planting pattern in which shrubs or small trees are planted closely together in single or double rows is called a hedge or green wall.

1. Types of hedges and green walls

(1) According to height, they can be divided into: green walls (over 160 cm), high hedges (120-160 cm), hedges (50-120 cm) and low hedges (below 50 cm);

(2) According to functional requirements and ornamental requirements, it can be divided into: evergreen hedges, flower hedges, fruit hedges, thorn hedges, deciduous hedges, vine hedges and woven hedges;

2. The role and function of hedges

(1) Scope and enclosure function Hedges are often used as defensive boundaries in gardens. They can be made of thorn hedges, high hedges, or hedges with barbed wire. Hedges can organize the routes for tourists to visit and tour according to the designated scope. Hedges can be used to enclose areas that you do not want tourists to pass through.

(2) Separating spaces and blocking sightlines. Hedges or green walls are often used in gardens to separate spaces with different functions and block sightlines. It is best to use evergreen trees to form a green wall above the sightline. For example, children's playgrounds, open-air theaters, and sports fields can be separated from quiet rest areas to reduce mutual interference. In a natural layout, there are partially regular spaces, which can also be separated by green walls to ease the strong contrast and different styles of layout forms.

(3) The middle hedge is used as the dividing line for regular gardens, and the low hedges are used as the edges of flower borders, flower beds and ornamental lawns.

(4) Evergreen trees are often trimmed into various forms of green walls in gardens as backgrounds for flower borders, fountains, and statues. As backgrounds for fountains and statues, the height of the green walls should generally be proportional to the height of the fountains and statues, and dark green trees with no reflections are preferred. Hedges used as backgrounds for flower borders are generally evergreen tall and medium hedges.

(5) Beautifying retaining walls In various green spaces, retaining walls between two high grounds at different heights are often planted with hedges in front of them to avoid dullness on the facade, thus beautifying the facade of the retaining wall.

3. Hedge planting density

The density of hedge planting depends on the purpose of use, different tree species, seedling specifications and the width of the planting area. For dwarf hedges and general hedges, the spacing between plants can be 30-50 cm, the row spacing is 40-60 cm, and the double-row hedges are arranged in a triangular fork. The spacing between plants of green walls can be 1-1.5 meters, and the row spacing is 1.5-2 meters.

Part 3. The essentials of garden lawn design                                                                                                                                    

1. The meaning and function of garden lawn

The grass in the garden is also called "lawn", which is the whole green ground in the garden cultivated by artificial turf or sowing grass seeds. In addition to soil and water conservation, dust prevention and sterilization, the grass has two unique functions in the city and the garden. One is that the green bacteria-covered land replaces the bare soil, giving the whole city a clean, fresh, green and vibrant appearance; the other is that the green carpet made of soft grass provides people with an ideal place for outdoor leisure activities. Large green grass gives people a sense of peace, coolness, kindness and comfort. Because grass herbaceous plants are particularly resistant to trampling and the plants are not tall, the grassy plants are always the main body of the garden grass, sometimes mixed with a small amount of other monocotyledonous or dicotyledonous herbaceous plants, sometimes single, and sometimes mixed.

Types of Garden Lawns

1. Classification based on grassland usage

Recreation lawn, ornamental lawn, sports lawn, pasture lawn, airport lawn, forest lawn, slope protection and bank protection lawn.

2. Classification based on grassland plant combinations

Pure grassland, mixed grassland, and flower-studded grassland.

3. Selection of grass species for garden lawns

The most important task of garden lawns is to meet the needs of tourists for rest and sports activities, so the grass species selected must be able to withstand trampling; in addition, garden lawns cover a large area and it is impossible to carry out large-scale artificial irrigation frequently, so the grass species selected must have good drought resistance.

Grass species adapted to the southern region: Bermuda grass, centipede grass, Zoysia japonica, and Zoysia ditchleaf.

4. Grassland slope and drainage

1. Requirements for soil and water conservation

In order to avoid soil erosion, collapse or collapse of the slope, the ground slope of any type of grassland should not exceed the natural repose angle of the soil (generally around 30°). For terrain with a slope exceeding this, engineering measures should generally be used to protect the slope.

2. Requirements for garden activities

For example, the grass field in a stadium should be as flat as possible, except that it must maintain a minimum slope for drainage. For general ornamental grass fields, pastures, forest grass fields and bank slope grass fields, as long as they are below the natural repose angle of the soil and above the required drainage slope, there are no special requirements for activities. For regular recreational grass fields, except that they must maintain a minimum drainage slope, their slope should not exceed 0.05 under normal circumstances. For natural recreational grass fields, the maximum slope of the terrain should not exceed 0.15. For general recreational lawns, about 70% of the area should have a slope that fluctuates within 0.1-0.05. When the slope is greater than 0.15, it is unsafe to carry out recreational activities because the slope is too steep, and it is also inconvenient for a lawn mower to mow the grass.

3. Drainage requirements

The minimum allowable slope of the grassland should be considered based on the drainage requirements of the ground.

4. Requirements for lawn shaping