Gardeners grow two types of plants basically, annuals and perennial plants. The annual plant grows from a seed; flowering follows and the mother plant dies after the new crop of seed has matured. The perennial plant does not have a life span that is limited to one year unless it is grown out of zone. For instance, the tulip bulb is a perennial plant when grown in the Netherlands, but in much of the United States, the tulip bulbs decline and won't flower again in many States, so that tulips are planted thereafter as an annual-not to return the following year. The environmental factors of heat and humidity limit the planting and growing of tulip bulbs in much of the United States as a perennial plant.

Elephant ear bulbs can be grown as a perennial plant in warmer climates where the elephant ear bulbs grows in size each year to form huge clumps. Elephant ear bulbs when planted in Northern States like New York will not survive outside temperatures of snow and ice and must be grown as an annual unless the elephant ear bulbs are dug up and stored inside the house.

From these perennial bulb examples, it can be demonstrated how important temperature factors are in plant survival. Other factors of the environment are important, such as light intensity. Yucca plants and agave plants thrive in hot, dry, sunny conditions, and if either of these plants are grown in low light, the decline begins that finally results in plant death.

Desert plants such as agave plants, yucca plants, and aloe plants can survive in the dry sands of the deserts and heat, drought, and intense sunlight that other plants could not tolerate. The yucca, agave, and aloe plants could not survive tropical jungle humidities and shade.

Fern plants are very adaptable to practically any environment imaginable, from rocky heights on arctic-like mountain tops, to the heavy shade of tropical rainforests, ferns thrive. As a nursery plant, ferns are grown as bedding plants in sun or shade or as delicate indoor potted fern plants such as the lacy maidenhair fern, Adiantum peruvianium, and the foxtail fern, Asparagus meyerii.

Groundcover perennial plants are important in controlling erosion and in reducing soil evaporation. Some groundcover plants form clumps and others, like ivy, form vines that can rapidly grow to cover uphill bare spots or cover walls and buildings. Ivy grows rampantly once established and is popular to use in planters and hanging baskets. Iron plant, Aspidistra lurida, grows well as a shade plant and some aspidistra forms are covered with white dots on the waxy green leaves; others are variegated with white stripes, Aspidistra elatior 'Variegata.' Palm grass, Curculigo capitulata, grows very well as a shade plant near pools. Dwarf mondo grass, Ophiopogon japonicus nana, is an excellent liriope-type groundcover that aggressively crowds out weeds and grows in green or white forms for landscape contrasts. The creeping fig vine, Ficus repens, rapidly covers walls and can cover ground areas that are barren. Ficus repens, fig vine, can rapidly send out leafy shoots that grow a foot per week. Liriope groundcover perennial plants are among the most popularly grown because they are colorful, dense, clean growing and grow in many sizes. The most popular liriope cultivars are Liriope muscari 'Big Blue;' Liriope muscari 'Royal Purple;' Liriope muscari 'Super Green Giant;' and Liriope muscari 'Variegata.

Flowering bush hydrangea perennials are native plants to the United States, and many new hydrangea cultivars have been developed in bright colors of red, blue, white, purple, and pink. Hydrangea bushes shed their leaves during the winter, but spring back to life in the spring, covered with flowers.

Flowering vine perennials are grown to cover fences, trellises, and walls-some with evergreen foliage, others with flowers with a bonus of many colors, including red, coral, blue, purple, pink, white, and yellow. Carolina jasmine, Gelsemium sempervirens, covers the entire vine with bright yellow flowers, which are fragrant and fast growing. Confederate jasmine, Trachelospemum jasminoides, flowers with yellow or white blooms, perfumed like other sweet jasmine vine perennials. Bleeding heart vine, Clerodendron thomsoniae, flowers bright red, heart-shaped blooms and climbs as a vine rapidly for privacy screens. Coral vines, Antigonon leptopus, are famous in the South for heart-shaped leaves and fragile delicate flower clusters of pink or white. Coral vines are known locally in Florida as the Tallahassee vine.

The butterfly bush is sweetly scented and easy to grow as a perennial bush or hedge. Butterflies swarm on the flowers in summer and fall seasons that are tough and can easily become established underneath pine trees in thickets, some are documented to have persisted for over 40 years in one place. Important flowering butterfly bushes flower in red, pink, purple, white, and yellow. The important cultivars grown are Buddleia lindeyana, Buddleia davidii 'Bonnie,' Buddleia davidii 'Pink Delight,' and Budlleia davidii 'White Profusion.

Ornamental grasses have secured an important place in the landscape garden. As a bedding plant, ornamental grasses such as black fountain grass, Egyptian papyrus, lemon grass, Pink Muhly grass, Red fountain grass, Umbrella grass, Tricolor society garlic, Northern sea oats, Pampas grass, Cortaderia selloana, and Japanese silver grass have found valuable placement in office building landscapes.

Angel trumpet plants (Datura) are very desirable to grow in warm climates. The trumpet flowers open as fragrant one foot blooms, drooping as the as the day progresses. Flowers of many datura, angel trumpet plants, cover the shrub all summer and fall in a blaze of color: red, pink, white, yellow, orange, purple, etc. These datura (angel trumpet) plants are readily hybridized into many attractive interesting color combinations, known technically as 'Brugmansia' x 'candida.