General principle: Choose plants with short plants and shallow roots. Tall trees have deep roots and large crowns, but the roof is windy and the soil layer is too thin, which is easy to be blown down by the wind. If the soil layer becomes thicker, it will increase the weight. Moreover, the developed roots of trees are easy to deeply tie the waterproof layer and cause leakage. Therefore, roof gardens should generally choose plants with relatively low roots, drought tolerance, cold tolerance and barren tolerance. There are mainly the following categories. Sedum: Sedum lineatum, Sedum sarmentosum, Sedum dentatum, Sedum aureum, etc. Local lianas: perennial herbs such as Catharanthus roseus and Ivy: short-flowered shrubs such as Dianthus caryophyllus, Thyme, Coreopsis, Aralia, Aster: short-flowered shrubs such as Lagerstroemia indica, Malva, Hibiscus, Buxus microphylla, Fusang and False Forsythia: white orchids, roses and snow. Roof garden is relatively high, windy, thin soil layer, long illumination time, large temperature difference between day and night, low humidity and low water content. You can choose flowers and trees that like light, are wind-resistant, cold-resistant, heat-resistant, drought-resistant, ridge-resistant and have strong vitality. It is best to use shrubs, bonsai, turf and other plants to meet the requirements of shallow soil layer, and try not to use trees with tall main roots. If it is used, it should be planted where the load-bearing columns and walls are located. Vines: grapes, fireworks, Parthenocissus tricuspidata, wisteria, lingxiao, ivy, honeysuckle, morning glory, etc. Hedges: boxwood, holly, Berberis, Japanese thorn plum, Ligustrum lucidum, pearl plum, hibiscus, etc. Pollution-resistant tree species: Ficus carica, Mulberry, Albizia Albizia, Hibiscus, Jasmine, Osmanthus fragrans, Palm, etc. Flower shrubs: Camellia, Rhododendron, Pyracantha fortunei, Forsythia suspensa, Rose, Yingchun, etc. Evergreen shrubs: Ficus, Ficus alternifolia, Liriodendron, etc. Ground cover plants: southern cherry blossom, sunflower, hanging bamboo plum, Pteris, velvet, etc. Zoysia japonica, weeds, Cong Lan, Ophiopogon japonicus, Ligustrum lucidum, etc.