Ontario gardeners know that timing and soil preparation are everything when selecting blooms that thrive in this region’s climate. Finding the best flowers to grow in ontario means choosing plants that can handle cold winters, humid summers, and sudden frosts. This guide covers top picks that will fill your garden with color from spring to fall.
Whether you have a sunny patch or a shady corner, there are flowers that will perform well. We’ll talk about perennials that come back year after year and annuals that give you a full season of blooms. Let’s get started with the most reliable choices.
Best Flowers To Grow In Ontario
These flowers have been tested by local gardeners and proven to handle Ontario’s unique weather patterns. They resist common pests, tolerate temperature swings, and don’t require constant fussing.
Black-Eyed Susan
This native wildflower is a superstar in Ontario gardens. It blooms from July to October with bright yellow petals and dark centers. Black-eyed Susans love full sun and well-drained soil. They are drought-tolerant once established, making them perfect for busy gardeners.
- Height: 2-3 feet
- Sun: Full sun
- Soil: Average, well-drained
- Bloom time: Mid-summer to fall
Lavender
English lavender varieties like ‘Munstead’ and ‘Hidcote’ do well in Ontario. They need full sun and sandy, alkaline soil. Lavender attracts bees and butterflies, and its scent is calming. Mulch with gravel to keep roots dry in winter.
Plant lavender in raised beds or slopes to improve drainage. Prune lightly after flowering to keep plants compact.
Peonies
Peonies are long-lived perennials that can bloom for decades. They need cold winters to set buds, which Ontario provides perfectly. Plant bare-root peonies in fall for spring blooms. Support heavy flowers with rings to prevent flopping.
- Choose a sunny spot with good air flow
- Plant eyes no more than 2 inches deep
- Water deeply during dry spells
- Cut back foliage in fall after frost
Daylilies
Daylilies are almost indestructible. They thrive in poor soil, tolerate drought, and bloom for weeks. ‘Stella de Oro’ is a popular reblooming variety. Divide clumps every 3-4 years to keep them vigorous.
Daylilies come in every color except true blue. They work well in borders, slopes, or containers.
Coneflower
Echinacea, or coneflower, is another native that loves Ontario. It blooms from July to September and attracts pollinators. Leave seed heads standing in winter for birds. Newer varieties offer colors like orange, green, and pink.
Coneflowers need full sun but tolerate light shade. They are deer-resistant and rarely need watering once established.
Annuals For Continuous Color
Annuals bloom all season until frost kills them. They are great for filling gaps in perennial gardens or for containers. Here are the best annuals for Ontario.
Marigolds
Marigolds are heat-tolerant and bloom from spring to frost. They repel some garden pests and are easy to grow from seed. French marigolds stay compact, while African marigolds grow tall.
Deadhead spent blooms to encourage more flowers. Marigolds do well in poor soil but need regular watering in containers.
Petunias
Petunias are workhorses in Ontario gardens. They come in trailing and upright forms. Wave petunias spread quickly and need little care. They prefer full sun but can handle some afternoon shade.
Pinch back leggy stems to keep plants bushy. Petunias are heavy feeders, so fertilize every two weeks.
Zinnias
Zinnias are fast-growing and bloom in bright colors. They are excellent for cutting gardens. Direct sow seeds after the last frost. Zinnias need full sun and good air circulation to prevent powdery mildew.
- Height: 6-40 inches depending on variety
- Sun: Full sun
- Soil: Rich, well-drained
- Bloom time: Summer to frost
Cosmos
Cosmos are easy from seed and bloom in pink, white, and orange. They tolerate poor soil and dry conditions. Cosmos can self-seed, giving you free plants next year. Cut flowers for bouquets to keep plants blooming.
Shade-Loving Flowers
Not every Ontario garden gets full sun. These flowers thrive in partial to full shade.
Hostas
Hostas are grown for their foliage, but they also produce lavender flowers in summer. They come in sizes from miniature to giant. Slugs can be a problem, so use slug bait or copper tape.
Hostas need consistent moisture and rich soil. Variegated varieties need more light to keep their pattern.
Bleeding Heart
This old-fashioned perennial blooms in spring with heart-shaped pink flowers. It goes dormant in summer, so plant it with later-blooming shade plants. Bleeding heart likes cool, moist soil.
Astilbe
Astilbe has feathery plumes in pink, red, white, and purple. It blooms in mid-summer and attracts butterflies. Astilbe needs consistent moisture and rich soil. It pairs well with hostas and ferns.
Impatiens
Impatiens are annuals that bloom non-stop in shade. They come in many colors and are great for containers. Water them regularly, as they wilt quickly in dry soil. New Guinea impatiens tolerate more sun.
Flowers For Pollinators
Ontario’s bees, butterflies, and hummingbirds need food sources throughout the season. Plant these flowers to support local wildlife.
Milkweed
Milkweed is essential for monarch butterflies. Swamp milkweed and common milkweed both grow in Ontario. They need full sun and tolerate wet soil. Milkweed spreads by seed, so remove seed pods if you want to control it.
Bee Balm
Bee balm has showy red, pink, or purple flowers that attract hummingbirds. It needs full sun to partial shade and moist soil. Bee balm can get powdery mildew, so space plants for air flow.
Butterfly Bush
Buddleia is a shrub that blooms from summer to fall. It attracts butterflies and bees. Prune it back hard in early spring. Some varieties are sterile and won’t spread seeds.
Tips For Growing Flowers In Ontario
Follow these practical steps to get the best results from your flower garden.
Know Your Hardiness Zone
Ontario ranges from zone 4 in the north to zone 7 in the south. Check your zone before buying plants. Most perennials sold at local nurseries are suited to your area.
Prepare Soil Properly
Ontario soil can be heavy clay or sandy. Add compost to improve drainage and fertility. Test your soil pH; most flowers prefer 6.0-7.0. Lime can raise pH, while sulfur lowers it.
Water Wisely
Water deeply once a week rather than shallowly every day. Morning watering reduces disease. Use soaker hoses or drip irrigation to keep foliage dry. Mulch with bark or straw to retain moisture.
Plant At The Right Time
Wait until after the last frost date to plant tender annuals. In most of Ontario, that’s late May. Perennials can be planted in spring or fall. Fall planting gives roots time to establish before winter.
Deal With Pests Naturally
Aphids, slugs, and Japanese beetles are common. Use neem oil for aphids, beer traps for slugs, and hand-pick beetles. Encourage beneficial insects like ladybugs and lacewings.
Seasonal Flower Care Calendar
Here’s a simple timeline to keep your garden on track.
Spring
- Clean up dead foliage from last year
- Divide perennials like daylilies and hostas
- Plant cool-season annuals like pansies
- Start seeds indoors for warm-season flowers
Summer
- Water during dry spells
- Deadhead spent blooms
- Fertilize annuals every two weeks
- Watch for pests and diseases
Fall
- Plant spring-blooming bulbs like tulips and daffodils
- Cut back perennials after frost
- Mulch tender plants for winter
- Clean up fallen leaves to prevent disease
Winter
- Protect plants with snow cover or mulch
- Plan next year’s garden
- Order seeds and bulbs
- Clean and store garden tools
Common Mistakes To Avoid
Even experienced gardeners make errors. Here are pitfalls to skip.
Planting too early is a big mistake. Ontario can have frost in late May. Wait until soil warms up. Another error is overwatering. Most flowers prefer dry soil between waterings. Overwatering leads to root rot.
Not deadheading reduces bloom time. Remove faded flowers to encourage more. Also, ignoreing spacing causes overcrowding and disease. Follow seed packet instructions for spacing.
Using too much fertilizer can burn plants. Use a balanced fertilizer at half strength. Finally, forgeting to harden off seedlings before planting outdoors. Gradually expose them to sun and wind over a week.
Frequently Asked Questions
What are the easiest flowers to grow in Ontario?
Marigolds, zinnias, daylilies, and black-eyed Susans are very easy. They need little care and bloom reliably. These are great for beginners.
When should I plant flowers in Ontario?
Plant perennials in spring or fall. Annuals go in after the last frost, usually late May. Bulbs like tulips go in during October.
Can I grow roses in Ontario?
Yes, choose hardy varieties like ‘Knock Out’ or ‘Canadian Artist’ series. Plant them in full sun with good air flow. Mulch heavily in winter for protection.
What flowers bloom all summer in Ontario?
Petunias, marigolds, zinnias, and coneflowers bloom from June to frost. Deadheading keeps them going. Some perennials like daylilies have a shorter bloom period but rebloom if deadheaded.
How do I protect flowers from Ontario’s winter?
Mulch perennials with 2-4 inches of bark or straw after the ground freezes. Remove mulch in spring. For tender plants, bring containers indoors or wrap with burlap.
Growing flowers in Ontario is rewarding when you choose the right plants. Stick with proven varieties, prepare your soil, and follow a simple care routine. Your garden will be full of color from spring through fall. Start with a few easy picks and expand as you gain confidence. Happy gardening!