1. Garden plants can show temporal and spatial changes

Garden space is a four-dimensional space including time. This space changes with time, which is mainly manifested in the seasonal evolution of plants. The natural growth law of plants has formed a four-season scene of "flowers in full bloom in spring, trees in summer, red fruits in autumn and vigorous branches in winter", which has produced a time-specific landscape of "spring breeze is green in Jiang Nanan" and "frost leaves are red in February flowers". With the growth of plants, the individual plants also change accordingly, from sparse branches and leaves to dense crown, which has an important impact on the landscape. According to the seasonal changes of plants, plants with different flowering periods are planted together, which makes a certain unique landscape in the same place at a certain period, giving people different feelings. The cooperation between plants and landscape architecture also shows different picture effects due to the seasonal changes of plants, which is much better than a pavilion standing there forever.

2. Using garden plants to create ornamental landscapes

Plant materials are one of the elements of gardening. This is determined by the unique shape, color and charm of garden plants. Isolated trees planted in gardens are often particularly eye-catching because of their dense crowns or lush flowers.

figure 1 isolated trees (Pinus taiwanensis), such as ginkgo biloba, Betula alnoides and Populus alba, are straight and imposing, and pine trees are vigorous and vigorous. These trees are often planted as isolated trees to form the main landscape of the garden.

Several trees are arranged according to a certain composition to form a bush, which can not only show the group beauty of Min trees, but also show the individual beauty of the trees. As a whole, there are hierarchical changes in height and distance, which can form a larger viewing surface. More tree combinations, such as group planting, can form a group effect.

fig. 2 schematic diagram of tree group planting, such as "Wan He Song Feng", "Pear Flowers Accompanied by the Moon" and "Qushui Hexiang" are all popular scenic spots. Choose a tree with flowers and fruits to create a small group of plants, that is, simple forests, such as bamboo forest, merlin forest and pine forest, which are traditionally favored in China, and are very popular in gardens. You can also use trees to change color in autumn to create an "autumn forest", such as Liquidambar formosana, Sapium sebiferum, Ginkgo biloba, Acer mono, Cotinus coggygria, Chongyang wood, etc., which can form a landscape of "frost leaves are redder than February flowers". Seeing plum blossoms in Meihua Mountain in spring and red leaves in Qixia Mountain in autumn has become the main content of Nanjing people's sightseeing. This form can not only be the main scene of composition, but also serve as a barrier to cover up some unsightly places in the garden green space. It is worth noting that the planting of various tree species must be clearly defined, scattered and well-organized, with one or two species as the mainstay, highlighting the theme. For example, on the open lawn, several trees stand tall, forming an ornamental center. Colorful herbal flowers form a beautiful picture according to a certain composition method, which is commonly called a flower bed. It uses the colors of flowers and plants to attract people. Generally, in the center of the city square, the gate and the square in front of the building, various flower beds are often used as the main scene, which has strong landscape effect. For example, the flower beds in the middle of the road in Xuanwu Lake Park, and the three-dimensional flower beds that have appeared in recent years, have been welcomed by people all year round because of their continuous bloom and gorgeous colors, and at the same time have a icing on the cake effect on the urban landscape.