Flowering plants all belong to the group called angiosperms. The growth stages of these plants are predictable and regular, unless something in the environment occurs to get in the way. A drought, a freeze, a heatwave---these kind of stresses interfere with the growth stages of flowering plants. The stages occur in cycles, some completing the cycle only once, while others, like trees, have many cycles, continuing to grow their entire lives.
Germination is the emergence of an embryonic plant from the seed. It doesn't happen automatically; otherwise, plants might sprout at the wrong time of year, then die. Instead, nature signals that it's time for germination by the warmth of soil, the amount of daylight, rainfall and other clues, the signal depending on the kind of plant and its typical environment. Some seeds must have a certain amount of cold weather to germinate.
When the conditions are right, the seed germinates, which results in sprouting. The first roots begin reaching down from the seed, while either one or two cotyledons emerge into the light. Cotyledons are green and leaf-like.
Vegetative Growth Stage
The plant grows rapidly during its next phase, adding crucial vegetative growth. Both roots and leaves are needed for food, the roots finding nutrients in soil, the leaves converting the energy of sunlight to sugar. All this is used for more growth.
Annuals, plants that live only one season, can only have one stage of vegetative growth. This isn't the case for biennials, which live for two seasons and have two vegetative growth stages. During the first stage of vegetative growth, biennials produce food storage organs like bulbs to fuel the second stage of vegetative growth.
Perennials, too---these living for at least three years---have more than one vegetative growth stage, adding stems, leaves and roots every growing season they live.
Flowers are the hallmark of the reproductive stage. Each starts off as a bud that grows from a stem of the plant, developing into a flower with up to four parts including female, male or both female and male organs. Male organs produce pollen that contains sperm with which to fertilize eggs contained in the female ovary of the flower.
Once pollination has occurred, seeds grow. Meanwhile the flower ages and begins withering, even as its ovary swells and ripens around the seed.
Annuals enter the reproductive stage only once. Biennials enter the reproductive stage in their second season, after the second vegetative growth stage. After seeds are produced, annuals and biennials age---senescence---and then die.
Perennials are more long-lived, and, in the case of trees, can live hundreds of years. It takes a few seasons before perennials begin to flower, how many seasons depends on the type of plant. After that, perennials settle into a pattern of vegetative growth, flowering and dormancy, producing many seeds over the years.