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Plant Life Cycles Explained

Over the years I have used gardening as a retreat from the rush of everyday life. Gardens offer a year round place of exercise and enjoyment

It can often feel like experienced gardeners have a secret language all of their own. The jargon they use might include plants and flowers with long-sounding Latin names, different terminology for types of plants that handle other growing conditions and climates, etc.—the list sometimes seems endless.

And yet, ultimately, we all have the same goal—to have a varied display of color and form around our home that keeps pace with ever-changing seasons.

We can all benefit from taking the time to understand a little more of the language and terminology used, especially those who are new to this outdoor past-time.

An idyllic garden scene

An idyllic garden scene

Gardening Terminology Can Be Frustrating for the Novice Gardener

Gardening can be such a vast subject with which to get a grip. That first visit to a garden nursery can be frustrating for new gardeners, especially when faced with the enormous array of plants and flowers on display.

Confusion is only added to when packaging and labels of would-be purchases come with labeling that uses terms such as "Hardy Annuals" or "Biennials." Just what does this mean?

Perhaps you have just acquired a house with a garden and are thrust into quickly having to maintain its appearance and impact—it can be quite daunting. Or perhaps you have become frustrated when that much-loved plant or flower fails to reappear the following year. Do you worry that you may have mistreated the poor thing and that it has died from neglect?

Well, worry no more—all plants have a natural life cycle. Some are short-lived—shining brightly like a rock-star for only one glorious season—while others live a more sedate and long-lived life, sometimes growing and maturing for years, if not decades.

Whichever your preferred choice of planting is, it helps to understand the different terminology used to describe the lifespan and weather conditions associated with your desired plant.

There are three gardening terms used to describe the length of a plant's lifespan. These are:

  1. Annual
  2. Biennial
  3. Perennial

What Are Annual Plants?

Annual plants live for one growing season and then die. During one season, the plant completes its entire life cycle of growth, from seed to flower, producing seeds of its own before finally dying.

If you like the idea of mixing it up and don't mind having to replant fresh and different flowers regularly, then annual plants could be your thing.

When planting annual flowers, the best that you can hope for is that some of their seeds may have fallen nearby and that new flowers spring up from these next year. However, this something of a gamble, and the only way to be sure of a renewed flower bed next spring is to replant.

You will often hear of gardeners using a technique called "dead-heading" to remove old flowers, preventing them from going to seed. This action encourages new flower growth and prevents unwanted seeding of nearby flower beds.

A selection of Annual Plants

A selection of Annual Plants

Annual Plants: An Ideal Choice for Gardeners With Limited Available Time

Annual plants are ideal for the new gardener who has limited time to spend looking after his land. They are fast-growing, high performing plants that once you have prepared the flowerbed, your involvement with maintaining these plants will be minimal for the remainder of the year.

What Are Biennial Plants?

Biennial plants have a life cycle of two years. In their first year, they grow, in their second and last year, they reproduce and die.

This type of plant starts from seed. In their first year, they produce roots, stems, and leaves. During their second year, they produce flowers or fruit, after which they perish and die.

A selection of Biennial Plants in bloom

A selection of Biennial Plants in bloom

What Are Perennial Plants?

What matters most to you when selecting plants for your garden? Is it to have plants that will stand the test of time and that will remain in place, growing away, year after year without the need to be continuously re-planted re-planted each season? If so, then planting perennial plants may be the ideal choice for you.

Perennials regrow every spring (they have a life-cycle of more than two years).

These plants survive through the winter, either as a plant visible above ground or out of sight as dormant roots below the ground before re-emerging the next year.

Perennials plants tend to be easy to care for plants. Like annual plants, they can produce a colorful display, but they also have the added advantage of not needing to be replaced every year. I use perennial planting to ensure that certain parts of my garden are as low maintenance as I can manage.

A selection of perennial plants and flowers

A selection of perennial plants and flowers

Lifespan by Plant Type

Type of PlantLifespanExample PlantsComments


1 Growing Season (1 year)

Dahlia, Geranium, Poppy, Petunia

Each year you buy seeds or seedlings and plant them. You fertilise and water them throughout the growing season. They flower and produce seed before they die and you pull them out.


2 Growing Seasons (2 years)

Delphinium, Forget-me-not, Sweet William.

In their first year they produce roots, stems and leaves. During the second year, they produce flowers or fruit, after which they reseed and die.


3 or more Growing Seasons (3 or more years)

Asters, Daffodils, Peonies.

Once these plants are established in the ground, they generally need less feeding and maintenance than annual plants. Their root system spreads more widely than annual plants and they fill out more space in your garden.

How to Read Seed Packets

So how do you know which type of plant or flower seed you are looking at when at a garden nursery or shop?

The vast majority of seed packets indicate this on the pack's reverse side, usually on the top left or right.

Herbaceous Perennials

These are non-woody plants (woody plants being trees and shrubs). Herbaceous plants have green and soft stems. They tend to grow very fast to produce flowers and seeds in a short elapsed time. It is usually small herbaceous plants that occupy otherwise barren land first, mainly due to them tending to be small, close to the ground, and producing lots of seeds.

Snowdrop – example of a plant with an herbaceous stem.

Snowdrop – example of a plant with an herbaceous stem.

Tender or Hardy Plants: What Does It Mean?

As well as needing to know how long your plant will survive, you will need to see if it can withstand the cold weather during the winter months.

Gardeners differentiate between a plant's ability to cope with winter weather or not by naming those plants that can function as HARDY and those that cannot as TENDER.

A couple of good examples of a "Hardy" plant would be a hedge or tree. These overwinter without much fuss and start regrowing again come spring. Not much for the new gardener to have to do here as they pretty much take care of themselves as they overwinter.

Tender plants, on the other hand, will need you to help them during the winter. An excellent example of this would be a tree fern. You may need to cover it with a fleece during the winter months—or if possible, bring it indoors.

The terms you may see related to this are:

  • Hardy
  • Half-hardy
  • Tender

So just what do these terms mean?

  • Hardy plants can cope with outdoor winter temperatures down to minus 15C. In other words, they can survive in the open ground all year round.
  • Half-hardy plants: while they may survive cold weather, they cannot survive heavy frosts and must be brought indoors during the winter.
  • Tender plants: this is something of a catch-all term to describe plants that do not thrive in cold weather. On occasions, this term can also describe plants that do not succeed in heat.

As you might expect, various gardening terms can be put together or paired to add more detail to the plant's description.

For example, "Perennial" and "Hardy" can be paired to describe a plant that regrows every spring AND can cope with very cold outside temperatures during the winter months.

This begs the following question: Can Annual plants be Hardy? The answer is yes; however, they tend not to have the same definition of hardy as used with perennial plants. Annual Hardy plants tend to be plants that can survive light to moderate frosts during spring and may require additional protection from the cold during a period of heavy frosting.

Herbaceous Annuals, Biennials, and Perennials

Plant TypeComment

Herbaceous Annuals

Strictly speaking, all annual plants are herbaceous. They have a short life-span and neither the time or the energy to develop anything but soft, non-woody stems.

Herbaceous Biennials

Plants whose stems die back after the first year, but which re-emerge the following growing season, flower and then die in their second year.

Herbaceous Perennials

Plants which die back each year. However, their roots or other underground parts survive through the winter.

Combining Gardening Terminology

Half-hardy annuals such as Rudbeckia, Dahlia, and Petunia die if exposed to the cold, so they can't go into the garden until after the last frost. Sown indoors in spring, they will keep going until killed by the first autumn frost.

Half-hardy biennial plants complete their lifecycle in two years, but like the half-hardy annual plants, they need winter protection.

What Is Overwintering?

This is the name given to the various methods of protecting your plants from the cold. You can do this by putting them somewhere sheltered from the elements. These methods may include:

  • Covering dormant plants with a thick layer of mulch – adequately insulating the plant.
  • Place plants in a cold frame
  • Place plants indoors – in a shed, windowsill or basement

To Harden Off a Plant

You might also have heard the term "harden off" a plant. This is a term used to describe the process of acclimatizing young plants growing in a protective environment to enable them to cope with cooler conditions outdoors. Normally done by leaving plants outside during the day and bringing them undercover at night.


The following resources were consulted in the creation of this article:

  • Hodgson, Larry. Annuals for Every Purpose. 2002.
  • Rosenfield, Richard. A Gardeners Guide to Perennials.
  • Cook, Ian. The Plant Finders Guide to Tender Perennials. 1998.
  • McHoy, Peter. The Practical Garden Companion. 1999.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2018 Ben Reed