Not sure how many of you like to purchase plants for your gardens, but if you do and you are not sure of what these terms mean then here is a guide I have put together that basically explains these 3 different categories of plant types which we all come across when visiting the garden centre, and which may seem a little bit confusing to the novice, but in fact the terms used simply group the plants by their life cycle.
Perennial
The word perennial simply means plants which flower reliably every year, usually growing in size each time, the stems die back over winter but the roots don’t, so the plant will regenerate the following year. Most plants in this category fall under the title ‘Herbaceous Perennials’, with the exception of Trees and Shrubs which don’t die back to ground level over Winter, these are sometimes referred to as ‘Woody Perennials’. There is a huge range of perennial plants, and they can be used for a wide variety of planting schemes, Perennials work especially well in borders, classic plants include Lilies, Salvia, Cranesbill, Peonies, Hydrangea, Campanula, Delphiniums, Alchemilla and Kniphofia (red hot poker) to name just a few.
There are also Evergreen perennials that keep their leaves throughout the winter such as Euphorbia, Helleborus and Tiarella, Perennial plants may set seed but a more common way to propagate them is by dividing established plants or to take cuttings.
Biennials
Biennial is a term used for plants which have a two-year life cycle, so during the first year they will grow only the roots, stems and leaves….and then in the second year they come into flower, produce seeds and then die. Pansies, Foxgloves, Wallflower, Hollyhocks, Evening primrose and Sweet William are all biennial plants; however there are some biennial plants that are grown as annuals, such as Parsley and Celery.
To ensure continuous yearly flowering of biennials, plant a new batch during the same year that the first ones actually come into flower, many biennials are also self seeders, meaning they spread seed around the parent plant.
Annuals
Annual is a term used for plants that are germinated, come into flower and then set seed before dying during one season or year, Hardy annual seeds are sown on the site where they will flower, Poppy, Cornflower and Nigella are all hardy annual flowers.
Half-hardy annuals are sown in pots and are kept sheltered in a greenhouse; these are then planted out later in the year when the risk of frost has finally passed, Half-hardy annuals include Cosmos, Lobelia and Nasturtiums.
Andrew Porter (Horticulturist)
Picture credit: Shutterstock
Perennial
The word perennial simply means plants which flower reliably every year, usually growing in size each time, the stems die back over winter but the roots don’t, so the plant will regenerate the following year. Most plants in this category fall under the title ‘Herbaceous Perennials’, with the exception of Trees and Shrubs which don’t die back to ground level over Winter, these are sometimes referred to as ‘Woody Perennials’. There is a huge range of perennial plants, and they can be used for a wide variety of planting schemes, Perennials work especially well in borders, classic plants include Lilies, Salvia, Cranesbill, Peonies, Hydrangea, Campanula, Delphiniums, Alchemilla and Kniphofia (red hot poker) to name just a few.
There are also Evergreen perennials that keep their leaves throughout the winter such as Euphorbia, Helleborus and Tiarella, Perennial plants may set seed but a more common way to propagate them is by dividing established plants or to take cuttings.
Biennials
Biennial is a term used for plants which have a two-year life cycle, so during the first year they will grow only the roots, stems and leaves….and then in the second year they come into flower, produce seeds and then die. Pansies, Foxgloves, Wallflower, Hollyhocks, Evening primrose and Sweet William are all biennial plants; however there are some biennial plants that are grown as annuals, such as Parsley and Celery.
To ensure continuous yearly flowering of biennials, plant a new batch during the same year that the first ones actually come into flower, many biennials are also self seeders, meaning they spread seed around the parent plant.
Annuals
Annual is a term used for plants that are germinated, come into flower and then set seed before dying during one season or year, Hardy annual seeds are sown on the site where they will flower, Poppy, Cornflower and Nigella are all hardy annual flowers.
Half-hardy annuals are sown in pots and are kept sheltered in a greenhouse; these are then planted out later in the year when the risk of frost has finally passed, Half-hardy annuals include Cosmos, Lobelia and Nasturtiums.
Andrew Porter (Horticulturist)
Picture credit: Shutterstock