Alyssum. Alyssum is a warm zone perennial plant, which means it can bloom all year in climates like California. It has small, fragrant white, pink or purple flowers and grows best in full sun.
The short answer is that annuals don't come back. Plants that flower and die in one season are annuals—although many will drop seeds that you can collect (or leave) to grow new plants in the spring.
The agave americana plant is known as a century plant because it typically blooms once every 100 years at the end of its life cycle.
Century Plant (Agave Americana)
The century plant was so named because it was originally thought to bloom once every 100 years; however, it actually matures and blossoms after 50 or 60 years at most.
In the Arid Greenhouse at the Chicago Botanic Garden, Agave ocahui is known as the century plant because people used to think it flowered only once every 100 years. A more accurate estimate is that it blooms once after 25 to 30 years of growth.
As rapid growers—averaging about 2 feet of growth per year—larger varieties of hydrangeas can reach up to 15 feet tall. Applicable in growing zones 3 to 9, hydrangeas are a low maintenance plant that will return year after year with proper care.
The corpse flower is one of the largest unbranched flowering plants in the world and blooms once every 7-10 years.
The hydrangea blooming season depends upon the type and cultivar as well as your planting zone. Most new growth hydrangeas put on buds in early summer to bloom in the following spring, summer and early fall seasons. In hot climates, hydrangeas may stop blooming in the heat of summer, but will rebloom in the fall.
Corpse Flower
The flower, native to the rainforests of central Sumatra, blooms once every 8 to 20 years, but when it does it opens up to 5 feet wide, or more, with a single dark-purple petal under a tall central stalk.
Delicate and dainty with small flowers, jasmine is known around the world for its unique tropical smell and pretty blossoms that attract bees. The jasmine flower is usually white, although some species are yellow or cream, and it can bloom all year long. Jasmine can grow in a pot or hanging basket.
Most common hydrangeas prefer a partial sun location - ideally receiving sun in the morning hours and shade in the afternoon. The reblooming Endless Summer® Hydrangea series prefers part shade. These include BloomStruck®, Endless Summer®, Blushing Bride®, and Twist-n-Shout®.
If you don't prune hydrangeas then they can eventually resemble a tangled mass of woody stems, and the flowers will become smaller and less showy.
Hydrangeas do not require strict reqular pruning; simply keep them healthy by removing dead wood and they will grow and flower well.
Cranesbill (Geranium), also known as true geranium or hardy geranium, is a perennial that blooms throughout the entire summer. This is not the same plant as annual geraniums (Pelargonium) that are used as bedding plants. Cranesbill will grow in full sun or partial shade.
The best month to plant flowers in spring is really down to the USDA hardiness zone you live in and the likely last frost date. This is likely to be from around March, but if you live in a northern zone, be sure to plant frost-tolerant perennials until you are happy that the risk to more tender flowers has passed.
The Middlemist Red flower is probably the rarest flower in the world, and it can only be found in London and New Zealand. The Chinese botanist John Middlemist brought this plant to London in 1804. The flower, formerly thought to have disappeared from London, is no longer present in Asia.
American agave plants are known for their fairly fatalistic life cycles: live, die, repeat. After blooming, the plants are expected to die shortly thereafter, usually leaving behind clones of themselves in the form of seeds.
The corpse flower (Amorphophallus titanum) is the largest unbranched inflorescence in the plant kingdom, boasts a powerful stink, and blooms for just 2-3 days once every year or two. The bloom can grow up to 8 feet tall! This plant fascinates visitors of all ages.