Plants can either be annual, biennial or perennial. It’s important to be able to differentiate between these three in order to plan your garden more efficiently.
In short, a perennial is a plant which returns year after year, but what then is the difference between a perennial and an annual, or even a biennial and why does it matter?
What’s the difference between a perennial, annual and biennial?
These three sub-categories of plants are the main ones used to differentiate between how many times and how often a plant returns each year/season, if at all. Knowing the difference between them is handy for a gardener to be able to plan their garden in accordance with which blooms will and won’t bloom again.
What is a perennial?
A perennial is a plant whose life expectancy is longer than that of other types of plants. Perennials tend to live for 3+ years, coming back year after year during their peak seasons, often larger and with more vibrancy than the previous year.
The stems and leaves of perennials may die back entirely, however the roots remain intact and the plant will regrow the following year. Perennials can be initially more expensive than annuals or other plants, however, as they last much longer they give you more value for your money in the long run so long as they’re looked after properly.
Some examples of perennials include foxgloves, lupins and hellebores.
What is an annual?
An annual is a plant which flowers and dies within the same year – it can however, be replanted the following year if you harvest its seeds.
An annual’s primary function is to reproduce and seed, thus if you dead-head the blooms before seed production, you’ll retain a constant flow of flora until first frosts.
Some examples of annuals are begonias, cosmos and verbena.
What is a biennial?
A biennial plant has a two-year life cycle and is quite similar to an annual in that in it flowers, produces seeds and dies, however this happens in its second year of life. In its first year the plant will often just grow roots, stems and leaves.
An example of a biennial plant is dianthus.
When do you plant perennials?
There are lots of different types of perennial plants and because of this there isn’t a set period of time to plant perennials, however, generally it is best to plant most perennials in spring (from March to May) or Autumn (September and October time).
It is always best to check the ideal planting time of the perennial you want to plant prior to purchasing.
Where do you plant perennials?
This can depend on what type of perennial you are planting, however, generally perennials are not too picky and can be planted in a planter or in a garden flower bed/border so long as there is enough space for the root system to adequately support the plant.
When do you cut back perennials?
It’s always worthwhile to trim your perennials back after they’ve reached the end of their flowering period, or you can leave the stems to provide food/shelter for wildlife and cut back in the spring instead.
After cutting back your perennials it’s best practice to mulch and fertilise to promote growth next growing season.
What is a hardy perennial?
If a perennial is described as ‘hardy’ it often means it can withstand low winter temperatures quite well and thus comes back year after year with no issues. Some examples of hardy perennials are astilbe plants and echinacea.
What types of perennials are there?
There are plenty of different types of perennial, from lavender and anemones to chrysanthemums and hostas. Coming in a range of different shapes, sizes and colours, there’s a perennial to suit your needs and outdoor space.