Ability of plants to tolerate cold temperature. In the US, you can find the cold hardiness at the USDA website.
Annuals are plants whose life cycle lasts only one year, from seed to blooms to seed. Removing the flowers as they fade prolongs the blooming cycle, but if left to produce seeds, many annuals will readily reseed themselves. Some plants are considered as annuals in the temperate areas, but they are perennials in the tropics.
Perennials are plants that can live many years, they grow in size and stature until reaching their full maturity. Although they live on longer, many perennials lose their vigor after 3-4 years, and should be replaced. Most perennial plants may be divided to produce new plants, or they may be grown from seeds or cuttings. Because of cold sensitive, many perennial plants in the tropics become annuals in temperate areas.
Shrubs are woody plants of relatively low height, having several stems arising from the base and lacking a single trunk; a bush. Many flowering shrubs attract birds with their berries and provide brilliant fall foliage. Many flowering shrubs are at their best when blooming and can be used frequently in landscaping. Many shrubs in these pages are tropical plants that require a warm climate to survive during Winter time.
Flowering trees always have a splendid display of mass-color when they are in peak blooming. Most of flowering trees in the temperate areas have peak blooming in the Spring. However, there some trees bloom in Summer or Fall. Depend on where they are grown, some trees may be considered as shrubs.
Vines are climbers, mostly grown on trellis for their mass flowers. These may be divided into woody vines, such as wisteria, kiwifruit, and common ivy, and herbaceous (non woody) vines, such as morning glory. Climbers can be trained to grow on walls, trellis, fences...
Grass is the common word that generally describes monocotyledonous green plants. They include some more specialized crops such as lemongrass, as well as many ornamental plants. Grasses in this site are ornamental grasses which are used in landscaping.
Weeds are any plant that crowds out cultivated plants, any unwanted plants that grown in the lawns, gardens or crop fields.