Begonia, a genus of tropical and subtropical plants, grow as perennials in warm climates and annuals elsewhere. Some species, such as Begonia grandis, or "hardy" begonia, grow in USDA zones 6 through 9. Begonias are best suited to USDA zones 9 (with protection) through 11, where minimum average temperatures range from 25 degrees F to 40 degrees F and above.
Water once a week when the top of the soil is dry. Water your plant at the soil line to avoid wetting the foliage, which can lead to powdery mildew. Rieger begonias can put up with less water than normal, but they will not survive having their roots constantly wet.
Rhododendrons and azaleas, both from the genus Rhododendron, have long been mainstays of late spring because of their spectacular clusters of showy blooms—plus, large green leaves that often stay green through winter. The flowers are usually tubular-, funnel-, or bell-shaped—and often fragrant. The leaves of the smaller azalea are usually pointed and narrow; the leaves of the rhododendron are generally large and leathery.
These shrubs prefer climates with adequate rainfall and moist summers. The two main azalea groups, evergreen and deciduous (varieties that drop their leaves in the fall) can be found in nearly every part of North America, from the frosty Canadian plains to tropical Florida. The rhododendron types are fussier, preferring environments where it is neither too hot nor too cold (Zones 5 to 8). They need a certain amount of chilling to develop strong flower buds.
Pansies are the colorful flowers with “faces.” A cool-weather favorite, pansies are great for both spring and fall gardens! Here’s how to keep your pansies growing and blooming. Pansies have heart-shaped, overlapping petals and one of the widest ranges of bright, pretty colors and patterns.
The pansy can be either annual or perennial, however, gardeners treat this plant as an annual because it prefers cool weather and gets too leggy in summers. There hasn’t been much success producing heat-tolerant pansies that can survive hot weather. However, pansies are surprisingly hearty in cold weather. They’ll survive a frost (even a hard freeze). Even if the blooms withers in the cold, the plants will often stay alive.