Late Summer Bloomers: Plants That Thrive in September
As the warmth of summer begins to fade, many gardens in Alberta start to wind down—but not all! September is a magical time when certain hardy perennials, annuals, and native wildflowers shine at their peak. These late bloomers not only extend the beauty of the season but also provide vital food for pollinators preparing for winter.
Why Late Bloomers Matter
Late-blooming plants play an important role in the ecosystem:
- Support pollinators like bees, butterflies, and hummingbirds with nectar when most other flowers are fading.
- Add colour and vibrancy to your garden when many plants have gone dormant.
- Create resilience in your landscape by staggering bloom times from spring through fall.
Top September Bloomers for Alberta Gardens
1. Asters (Symphyotrichum spp.)
- Bright purple, pink, or white star-shaped flowers.
- Loved by bees and butterflies.
- Alberta-native varieties like Smooth Aster thrive in well-drained soil.
2. Goldenrod (Solidago spp.)
- Tall spikes of golden-yellow flowers.
- Often misunderstood as a cause of allergies (the real culprit is ragweed!).
- Provides late-season nectar and pollen for native pollinators.
3. Rudbeckia (Black-Eyed Susan)
- Cheerful yellow blooms with dark centres.
- Long-lasting colour from mid-summer into fall.
- Drought-tolerant and perfect for prairie gardens.
4. Sedum (Stonecrop, esp. ‘Autumn Joy’)
- Succulent foliage with clusters of pink-red blooms.
- A magnet for butterflies in September.
- Hardy and low-maintenance.
5. Helenium (Sneezeweed)
- Vibrant daisy-like flowers in orange, red, and yellow shades.
- Extends colour into late fall.
- Pairs beautifully with ornamental grasses.
6. Joe-Pye Weed (Eutrochium maculatum)
- Tall, sturdy native perennial with mauve-pink flower clusters.
- Thrives in moist soil—great for low spots in the garden.
- Provides nectar for monarchs and swallowtails on migration.
7. Native Wild Sunflowers (Helianthus spp.)
- Bright, bold blooms that thrive even in cooler weather.
- Attract pollinators and later provide seeds for birds.
Looking Ahead
September bloomers remind us that gardens don’t end with summer—they evolve. By incorporating late-blooming plants, your landscape will buzz with colour and life right up until the first frosts.
Visit the Trochu Arboretum in September to see late bloomers in action and get inspired for your own garden!
Tips for a September Garden
- Plant for pollinators: Clusters of the same plant species make it easier for bees and butterflies to forage efficiently.Late Summer Garden Tips
- Deadhead wisely: Removing spent blooms from earlier plants can encourage a last flush of flowers.
- Mix natives and ornamentals: Asters and goldenrod blend beautifully with sedum and rudbeckia.
Did You Know?
- Many late-blooming perennials are critical food sources for pollinators preparing for migration or winter hibernation.
- Plants like aster and goldenrod provide some of the last nectar sources of the season.
- Deadheading spent blooms on certain plants (like coneflowers) can extend flowering into September.
Quick Care Tips for September Bloomers
- Water deeply but less often to encourage strong root systems before frost.
- Add a layer of organic mulch to keep roots insulated as temperatures begin to cool.
- Avoid heavy fertilizing—plants should be hardening off for fall, not pushing new tender growth.
Pollinator-Friendly Picks
- Aster – Late nectar source for butterflies.
- Goldenrod – Supports bees and migrating monarchs.
- Echinacea (Coneflower) – Provides seeds for birds like goldfinches.
Leave a Reply