Plant Types Ultimate Guide: Annual, Biennial, Perennial, Shrubs & Trees
When you’re new to gardening you tend to find yourself buying plants that simply look nice in the garden centre without considering what plant type they are. This can lead to disjointed gardens or though that look nice for a few weeks and then return to their bland previous state.
By understanding the 5 different plant groups of classifications you can ensure your garden has both year-round interest and is set up to encourage wildlife into the garden. However, it can be daunting looking at the variety of plants on offer and trying to understand what should go where and how long the plant will live for.
Plant Type Groups Explained
The good news is nearly all plants can be split into different ‘lifecycle’ types or ‘classifications’ of plants. As you need all 5 in any garden knowing which group they belong to will help you work out exactly what plants you are looking for when shopping or growing.
Rather than getting overwhelmed, I believe it’s best to start with the most relevant to a new or weekend gardener.
To help you get more familiar with garden plant types I’m going to group them into 5 areas:
1.What is an annual plant?
Annual plants are those that germinate, grow, flower, potentially set seed if not sterile, and then die within a year.
Annual plants are the show-offs in the garden. They provide colour for one year and then usually they die off after Autumn.
There are two main types of annual:
- Half hardy Annuals
- Tender Annuals
Half-hardy annuals can be sown outside during the colder early spring months so they can get established. Tender annuals – like Busy Lizzies – cannot withstand frost or cold temperatures so can only exist outside in late Spring through to Autumn.
Examples of Annual Plants:
- Impatiens walleriana – Busy Lizzie (Tender Annual)
- Pelargoniums (Tender Annual)
- Nastrutiums (Half-hardy Annual)
- Cosmos (Half-hardy Annual)
Whats the difference between an annual and perennial plant?
The main difference is that annual plants only live for one year and then die. Perennial plants come back year and year and are considered a more long term and an ethically carbon-conscious way to garden.
2.Biennial Plants Explained
Biennial plants have a 2-year lifespan.
In year one they germinate, grow foliage and establish their roots. Then in year 2 they flower, set seed and die.
Examples of Biennial Plants:
- Nigella damascena -Love in the Mist
- Digitalis pupurea -Foxglove
- Myosotis sylvatica – Forget-me-nots
3.Perennials & Herbaceous Perennials
This group of plants is where the real fun starts. These are plants that live for longer than 3 years, sometimes up to 30 years plus.
Herbaceous perennials come back year after year. So once they are established they keep coming back every year keeping your garden borders full with minimal intervention from you apart from a good yearly prune and or some staking.
Herbaceous perennials provide amazing value for money and provide essential pollen and a food source for wildlife in our gardens. There are hundreds of thousands of different species of herbaceous perennial meaning you have a huge choice.
Herbaceous perennials can be grown and propagated from seed, split from existing perennial plants or planted as bare roots. Making them incredibly versatile to help any kind of gardener plant up their garden on a budget.
Half Hardy vs Hardy Perennials
There is also a distinction between hardy perennials – those that can be left outside all winter (Rudbeckia or Ornamental grasses such as Miscanthus) and half-hardy perennials that need protection during the winter months (Dahlias are a good example of half-hardy perennials).
Examples of Herbaceous Perennials
- Rudbeckia hirta – Black Eyed Susan
- Miscanthus sinesnsis – Chinese Silcver Grass
- Achilea flipendulina – Yarrow
- Salvia nemorsa ‘Caradonna’ – Woodland Sage
4.Shrubs
Shrubs are the backbone or structure of any successful garden design and flower bed. They offer year-round structure as they don’t disappear back to the ground each winter.
Garden Shrubs come in two distinct types:
- Evergreen shrubs that keep their leaves through the winter
- Deciduous shrubs that lose their leaves in the winter
Shrubs have woody stems compared to the fleshy stems of annuals, biennials and herbaceous plants. They can live far longer than the previous three plant types and offer a habitat for a much greater selection of wildlife, such as birds, mammals, insects and beetles.
Shrubs can act as permanent garden structures throughout the year. Using shrubs in a garden design or planting plant can help bring depth and year-round interest to a garden. They are important to help add structure and punctuation to a gardens structure.
Difference between a shrub and a tree?
Shrubs differ from trees as they have multiple stems or branches rather than a single trunk. Shrubs tend to be smaller than trees and can be pruned into distinct shapes. There are exceptions to these rules with shrubs that can grow to the height of a tree or a tree that can be pruned into a multi-stem for example.
Examples of Shrubs
- Rhododendron ‘Praecox’ – Rhododendron
- Viburnum tinus – Common laurustinus
- Cornus alba ‘Sibirica’ – Dogwood
- Hebe ‘Mrs Winder’ – Hebe
5.Trees
Trees are the final, vital and sometimes overlooked plant type in the garden. Trees provide height, control shade, offer a habitat for birds and can help address flood risks.
Trees usually have one main stem (though they can be multi-stemmed) and grow far taller than shrubs. They too come in either evergreen or deciduous forms.
There are a plethora of trees suitable for gardens of all sizes. In smaller gardens, fruit trees are a fantastic way to increase height without worrying about trees growing too tall.
Examples of Trees
- Acer campestre – Field Maple
- Acer palmatum ‘Bloodgood’ – Japanese Maple
- Malus domestica – Common Apple Tree
- Ginkgo biloba – Maidenhair tree
How to design a flower bed with plant types
Now that you know the 5 different plant groups you can now use these to create fantastic flower beds. By planting a variety of the 5 groups you can help encourage a host of wildlife to the garden helping mother nature and helping to reduce your carbon footprint along the way.
If you want to know more about how to arrange these plants I suggest you read my flower bed design guide here or watch the video below.
Summary of Plant Types
Incorporating the 5 types of plants into your garden will help create rich immersive spaces rather than seasonal throwaway flower beds. You’ll find yourself weeding less often, saving money and watching as wildlife flocks to your garden!
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Happy Gardening!
