What do the terms perennial, biennial and annual mean?

These plants are ones that flower reliably every year. Usually get bigger each time. The stems die back over winter, but the roots don’t. Meaning the plant can regenerate the following year.

Herbaceous

Most plants in this category fall under the title ‘herbaceous perennial’. Trees and shrubs, which don’t die back to ground level over winter are sometimes referred to as ‘woody perennials’.

Range

There is a huge range of perennial plants. And they can be used for a wide variety of planting schemes. Perennial’s work particularly well in beds and borders. Blooms such as lilies, Salvia, cranesbill, peonies, hydrangea, campanula, delphiniums, Alchemilla and Kniphofia (red-hot pokers) are eye catching additions.

Evergreen

Also, there are also evergreen perennials that keep their leaves through the winter months, such as Euphorbia, hellebores and Tiarella.

Perennial plants may set seed, but a common way to propagate them is by dividing established plants or taking cuttings.

Biennial plants have a two-year life cycle. During the first year, they grow only the roots, stems and leaves. In the second year they come into flower, produce seeds and die.

No gap planting

To ensure continuous flowering year after year, plant a new batch during the year that the first plants come into flower. Many biennials are also self-seeders, meaning they spread seed around the parent plant.

Pansies, foxgloves, wallflower, hollyhocks and evening primrose are all examples of biennial plants. Some biennial plants are grown as annuals, such as parsley and celery.

These are plants that germinate, come into flower, set seed and die in one season or year. By harvesting the seeds, you can grow them year after year.

Hardy annual seeds are sown in the particular site where they will flower. Examples of hardy annuals are poppy, cornflower and Nigella.

Half and half

Half-hardy annuals are sown in pots and kept sheltered in a greenhouse. These are then planted out later in the year when the risk of frost has passed. Half-hardy annuals include cosmos, Lobelia, and Nasturtiums.

The most prolific flowering summer bedding plants are annuals sown from seed and they include marigold, petunia and pelargoniums.