What are annuals, biennials and perennials?

Getting to know the life cycle of plants that you want to grow and eat

Post by Wendy Knerr on behalf of Replenish

If you grow your own fruit and veg, or want to get started growing, you might see different plants described as annual, biennial or perennial. These terms relate to the life cycle of a plant – the amount of time it takes for the plant to grow from seed, through the flowering and fruiting stage, all the way until it produces its own seed. 

Why does the life cycle of a plant matter? 

Knowing the life cycle tells you when you can expect a plant to produce the things you want to eat, and when it’s reached the end of its life and is ready to be cut back or pulled out. It can also give you an idea of where to plant a vegetable, herb or fruit: a plant with a longer growing cycle will need to stay in the ground longer, so you’ll need to find a place where it won’t be disturbed for a longer period of time.

Annuals – a whole life cycle in one growing season

The life cycle of an annual usually starts in the spring and ends in the autumn. Annuals go from seed to flower and back to seed in one season, and at the end all of their parts, including stems and roots, die back. 

Most common vegetables are annuals: you plant their seeds in the late winter or spring, and by autumn they’ve completed their life cycle and you need to pull out the dried stalks or stems and often the roots of the plant and put it on the compost pile or in a green waste bin. Depending on the plant, you might be able to collect some of the seeds from the plant and dry them for planting next year

Annuals include:

aubergine

runner and French bean

lettuce

pumpkin

tomato

peppers

courgette

Image by Raiona from Pixabay

Biennials – two years to complete a life cycle

Biennials are plants that grow during one season and then bloom the following spring. They benefit from the cold during winter. These plants will stay in the ground longer than annuals, so you may want to give them space away from any annuals that you plant. That way, when you pull up the annuals at the end of the season, you don’t disturb the roots of the biennials.

Biennials include:

beetroot

Brussels sprouts

cabbage

carrot

celery

chard

some leeks

many onions

swede

herbs like parsley and sage

Image taken by Wendy at Sandy Lane Farm

Perennials – longer to produce flowers and fruit, but come back year after year

Perennials take longer to complete their life cycle than annuals or biennials, and usually don’t produce fruit or flowers in their first year. But they’re worth the wait, because they come back year after year from the same planting, and in some cases get bigger each year.

At the end of the growing season, instead of pulling out the plants, you leave them where they are and they will produce again next year, though you may prune or otherwise cut back some of the growth.

Most fruits are perennials – think raspberry and blackberry bushes that produce fruit year after year – and many herbs are perennials, including chives, mint, and rosemary. Perennials need to be planted in a place where their roots won’t be disturbed for many seasons or years.

Image taken by Wendy at Sandy Lane Farm

Perennial vegetables include:

Asparagus

Expensive in the shops, and best when picked and eaten fresh in May; ready to harvest after two years and can continue to produce for up to 20 years!

Jerusalem artichokes

Unrelated to the more well-known globe artichoke, these are relatives of the sunflower; they are grown for their roots or tubers, which can be harvested from November onward and look like gnarly potatoes; they are eaten raw, roasted or in soups.

Left: image by Kohei Tanaka from Pixabay, right: image by Beverly Buckley from Pixabay

Perennial onions and garlic

These include Egyptian walking onions, which grow tall leaf stalks with clusters of little bulbs at the top; as the stems dry and fall over, the tops can take root in surrounding soil and grow into new plants; so it’s as if the plant is ‘walking’ round the garden, popping up in new places each year. Other perennial onions are Babington leeks and garlic chives.

Rhubarb

This is a vegetable, not a fruit, but most of us know it as the basis for delicious crumbles and other puddings. The plant can grow for many years and needs space where its thick, deep tap root won’t be disturbed, and where it will produce new stems year after year. It’s the stems that you can pick and cook with, but never eat the leaves – they can be toxic.

Left: image by Sergio Cerrato – Italia from Pixabay, right: image by Wendy Knerr

Want more tips? Check out our other grow-your-own guides

Follow us on social media or sign up to our newsletter.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: