What’s the Difference Between Annuals, Biennials, Perennials, Shrubs & Trees? 

Ever wandered through a garden centre and felt personally victimized by the word “biennial”? You’re not alone. With so many plant terms floating around—annuals, perennials, shrubs, trees—it can feel like you need a horticulture degree just to pick a petunia. Luckily, you don’t. That’s what we’re here for.

Understanding the basic life cycles and classifications of plants helps you plan, plant, and maintain a thriving garden that looks good not just today, but year after year. Let’s break it all down in plain English—with proper horticultural definitions, zone 5 examples, and tips to help you choose what’s right for your garden.

 

Annuals: The One-Season Wonders

Horticultural Definition:

An annual is a plant that completes its entire life cycle—from germination to seed production to death—within a single growing season. 

What this means for your garden:

These are your instant gratification plants. They germinate, grow quickly, flower profusely, and then die once frost hits. They're perfect for filling in gaps, creating vibrant containers, or changing up your colour scheme every year. 

Pros:

• Continuous blooms from spring to frost
• Great for containers, baskets, and garden borders
• Quick to establish
• Often inexpensive

Cons:

• Must be replanted each spring
• Not cost-effective long-term
• Can require more watering and deadheading

Popular Picks: 

• Petunia – Versatile and long-blooming
• Marigold – Pest-repelling and heat-tolerant
• Zinnia – Bright, bold, and butterfly-friendly
• Snapdragon – Cold-tolerant and adds vertical interest
• Impatiens – Perfect for shady spots

Pro tip: Many annuals can be started from seed indoors in March or April for early blooms.

Biennials: The Two-Year Teasers

Horticultural Definition:

A biennial is a plant that requires two growing seasons to complete its life cycle. In the first year, it produces vegetative growth (leaves, roots); in the second, it flowers, sets seed, and then dies.

What this means for your garden:

They’re in it for the long haul. Year one is leafy and low-key. Year two is when they really shine. Some may self-seed and naturalize in the garden, making them behave almost like short-lived perennials.

Pros:

• Can be dramatic bloomers in year two
• Many are pollinator-friendly
• Some self-seed and return on their own

Cons:

• No flowers in year one
• Can be easily forgotten if not labeled
• Short-lived by nature

Popular Zone 5 Picks: 

• Foxglove (Digitalis) – Towering spikes in year two
• Hollyhock – Classic cottage garden favourite
• Parsley – Yes, your herb garden has biennials too!
• Sweet William (Dianthus barbatus) – Fragrant and colourful
• Canterbury Bells – Bell-shaped blooms in pastel shades

Pro tip: Plant biennials two years in a row for continuous bloom coverage.

 

Perennials: The Long-Term Relationship

Horticultural Definition:

A perennial is a plant that lives for more than two years, typically flowering annually after its first year of growth. In cold climates, the above-ground parts often die back each winter, but roots survive and regrow in spring.

What this means for your garden:

Perennials are the reliable friends in your garden. They come back year after year, often with more vigour as they mature. Some may bloom only briefly each season, so it’s smart to layer different types to keep your garden interesting from spring to fall.

Pros:

• Low-maintenance once established
• Cost-effective over time
• Wide variety of colour, texture, and height
• Many are pollinator-friendly

Cons:

• Some take a few years to reach full potential
• May require dividing or thinning
• Limited bloom time compared to annuals

Popular Zone 5 Picks:

• Coneflower (Echinacea) – Drought-tolerant, loved by bees
• Daylily (Hemerocallis) – Tough, colourful, and dependable
• Peony (Paeonia) – Show-stopping blooms in early summer
• Hosta – Great for shade and lush foliage
• Black-Eyed Susan (Rudbeckia) – Bright and bold late-season bloomer

Pro tip: Cut back dead foliage in fall or spring to keep things tidy and disease-free.

Shrubs: The Workhorses with Woody Stems

Horticultural Definition:

A shrub is a woody plant with multiple stems, generally smaller than a tree, that persists year after year without dying back to the ground.

What this means for your garden:

Shrubs provide structure, form, and often year-round interest. They can be deciduous (lose their leaves in winter) or evergreen (keep their leaves all year). Many offer seasonal bonuses like flowers, berries, or vibrant fall colour.

Pros:

• Provides structure and form
• Multi-season interest (flowers, fruit, foliage, winter bark)
• Excellent habitat for birds and pollinators
• Can be used as hedges or focal points

Cons:

• Requires pruning and shaping
• May outgrow their space
• Initial cost is higher than smaller plants

Popular Zone 5 Picks:

• Hydrangea (Hydrangea paniculata) – Late summer blooms
• Ninebark (Physocarpus opulifolius) – Tough, colourful foliage
• Burning Bush (Euonymus alatus) – Fiery fall display
• Lilac (Syringa vulgaris) – Classic spring scent and bloom
• Boxwood (Buxus) – Evergreen and formal

Pro tip: Prune shrubs at the right time—early bloomers after flowering, summer bloomers in early spring.

 

Trees: The Giants of the Garden

Horticultural Definition:

A tree is a perennial woody plant typically with a single main stem (trunk), supporting branches and leaves. Trees are usually taller and longer-lived than shrubs.

What this means for your garden:

Trees are foundational landscape elements. They provide shade, structure, and environmental benefits. Many also flower or produce fruit. Whether ornamental or functional, trees create vertical interest and long-term impact.

Pros:

• Increases property value
• Offers shade, cooling, and windbreaks
• Provides habitat for birds and beneficial insects
• Can be low-maintenance once established 

Cons:

• Requires space to grow
• Takes years to mature
• May need professional pruning or removal eventually 

Popular Zone 5 Picks:

• Autumn Blaze Maple (Acer × freemanii) – Brilliant red fall colour
• Serviceberry (Amelanchier canadensis) – Four-season interest
• Crabapple (Malus spp.) – Showy flowers, great for pollinators
• Amur Maple (Acer ginnala) – Compact size, vibrant fall foliage
• River Birch (Betula nigra) – Unique bark and good near wet areas 

Pro tip: Fall is the ideal time to plant trees—cooler temps mean less stress for roots.

The Big Picture: Layer Your Landscape

Each plant type serves a purpose. Annuals deliver colour. Biennials add surprise. Perennials keep coming back. Shrubs give structure. Trees create the canvas.

In a well-designed garden, you’ll find a healthy mix of all five. This layering adds dimension, seasonal interest, and resilience. Whether you’re building a new garden or refreshing an old one, knowing the difference between these plant types helps you make smart, sustainable choices.

 

Need Help? Come See Us!

Whether you’re starting from scratch or need help identifying what's what in your garden, Georgina Garden Centre is here to help. We’ll help you pick plants that thrive in Canadian Zone 5, guide you through planting and care, and maybe crack a few jokes while we’re at it.

Got a question? Ask us. Need a plant? We’ve got ‘em. Just want to walk through and inhale the scent of soil and success? Come on in.

Happy gardening!