Native Asters for Ontario Gardens

There are over 32 different species of Aster (Aster, Doellingeria, Eurybia, Oclemena or Symphyotrichum) in Ontario, each with special adaptations to the particular habitats they are found in from the driest prairie to the wettest marsh. With so much diversity, it’s no surprise that they have become a "Swiss army knife" in natural garden design, providing gardeners with many different options for increasing wildlife value, beauty and function in their gardens.

How asters will help your garden thrive:

• Increase Diversity

  Asters are a very diverse group of plants. They come in a multitude of different colours including hues of blue, lavender, purple, pink and white. They also have a wide diversity of cultural needs. Dry shade? Try Large-leaf Aster. Wet soil? Try Purple Stemmed Aster. Hot/dry soil? Try Heath Aster. Whatever conditions you have in your garden, there is likely an Aster for that.

• Provide Host Plants

  The leaves of Aster are also known to feed caterpillars of around 112 butterfly and moth species, including the Pearl Crescent butterfly. By feeding the caterpillars, we are more likely to see the adults butterflies and moths in our gardens. In addition, by feeding caterpillars, energy can be moved up the food chain to birds and other wildlife. In fact, 97% of bird species feed their young insects, not seeds or berries. By providing high quality host plants such as Asters, you can help ensure that birds have enough food to raise their young.

• Pollinator Power-houses

  Fall blooming flowers such as asters are especially important to ensure that pollinators such as Bumblebee Queens have the energy they need before going into hibernation. Late blooms are also important for migrating species such as Monarch butterflies who need to stock up on energy for their trip to Mexico. You will commonly find both Bumblebees and Monarchs on Asters.

• Specialist Native Bees

  The copious amounts of pollen in the flowers attract a wide variety of pollinators, including specialist bee species that simply cannot feed on anything else!

• Juglone Tolerant

  Asters are juglone tolerant, meaning you can grow them near Walnut trees! Read more about juglone tolerant native plants.

The best asters for your garden

• Calico Aster (Symphyotrichum lateriflorum)

• Large-leaved Aster (Eurybia macrophyllus)

• New England Aster (Symphyotrichum novae-angliae)

• Swamp Aster (Symphyotrichum puniceum)

• White Wood Aster (Eurybia divaricata)

• Heath Aster (Symphyotrichum ericoides)

• Heart-leaf Aster (Symphyotrichum cordifolium)

• Smooth Blue Aster (Symphyotrichum laeve)

• Flat-topped White Aster (Doellingeria umbellata)

• Panicled Aster (Symphyotrichum lanceolatum)

Calico Aster (Symphyotrichum lateriflorum)

Sun: Part shade - sun

Height: 2-3 feet tall

Blooms: White, August - October

Soil: Sand, loam, clay

Moisture: Moist - dry 

Calico Aster is one of our most abundant aster species in Ontario. You can find it along forest edges, open woodlands and meadows.  

In your garden it will do well in part shade to full sun with moist to dry soil (if planting in full sun make sure the soil is more on the moist side). Calico aster will accept clay soils and grows well with Walnut trees too! It grows low and can handle some shade so it makes a great under-story plant in meadows and gardens with taller plants. 

Numerous white blooms begin in late summer and continue well into fall, providing a great food source for late season pollinators. I have noticed that the flowers are very popular with wasps(which is a good thing because wasps are natural enemies and control pests in our gardens!). 

I like pairing calico Aster with Zigzag Goldenrod (Solidago flexicaulis) or Bluestem Goldenrod (Solidago caesia). The white flowers of the Aster really make the yellow of the Goldenrods pop.

Large-leaved Aster (Eurybia macrophyllus)

Sun: Part shade - shade

Height: 1-3 feet tall

Blooms: Light blue-white, August - September

Soil: Sand, loam, clay

Moisture: Dry - medium

Large-leaf Aster, known as migiziwibag by the Anishinaabe, is a valuable plant for shade gardens. It begins the growing season as an attractive ground cover(spreading via rhizomes) with rough, heart-shaped leaves.

Through late summer and into fall, flat-topped clusters of light purple, daisy-like flowers will poke up from the leaves, reaching about 2 (sometimes 3) feet tall.

If your garden has part sun to dappled shade with average, well drained soil then you shouldn’t have a problem growing this - it’s quite adaptable. It’s a great native plant for sand and clay soils as long as they have some organic matter mixed in. Mine are thriving under large Sugar Maple trees. 

This pollinator magnet will be alive with native bees and the occasional butterfly too. 

Large-leaf Aster looks great with Bluestem Goldenrod (Solidago caesia) and the finer textured leaves of sedges (Carex spp.). It also grows well in the dry shade of large trees such as Sugar Maples. Grows well under Walnut trees.

New England Aster (Symphyotrichum novae-angliae)

Sun: Full sun - Part sun

Height: 2-5 feet tall

Blooms: Purple, pink, August - October

Soil: Sand, loam, clay

Moisture: Moist-average soil. Tolerates dry soil but may look scraggly.

New England Aster, known as waanisikensiwang by the Anishinaabe, is commonly found in meadows, fields and roadsides where it compliments the yellow of Goldenrods. You can bring this vibrant display(and the butterflies that come with it) into your garden too as New England Aster is very easy to grow. 

If you have rich, moist soil with sun to light shade then you can grow this with ease. It will grow in drier soils but may get leggy. This isn’t a problem as you can plant it with lower growing native plants that will hide the base. I like to plant it with Little Bluestem. Pinching back the stems before mid-July will help provide you with a more bushy form. 

Like many native plants, New England Aster can have slight variations in bloom colour. I have seen flowers with the darkest of purples all the way to pink. 

This is one of our latest blooming plants, often blooming until its hit by a few hard frosts. Bees and butterflies frequently visit New England Aster. It especially important for migrating Monarch butterflies.

Swamp Aster (Symphyotrichum puniceum)

Sun: Full sun - Part sun

Height: 2-5 feet tall

Blooms: Purple, light purple, August - October

Soil: Sand, loam, clay

Moisture: Wet - moist.  

There really is an aster for every growing condition, including wet soil! Swamp Aster, known as wiiniziikens by the Anishinaabe, is a moisture loving flower and is commonly found growing around wetlands, floodplains and shorelines. In your garden it will do well in wet to moist soil in full sun to light shade. It will tolerate drought once established but it may loose foliage and become scruffy so you are best planting it in a spot where the ground doesn't dry up. It actually works very well in rain gardens. 

Swamp Aster grows well with other moisture loving plants such as Joe-pye Weed, Swamp Milkweed and Turtlehead. This is a plant combination that you can find growing in the wild so you know that its meant to be!

The nectar and pollen attracts a wide diversity of pollinators including bumblebees, native solitary bees and butterflies such as skippers.

White Wood Aster (Eurybia divaricata)

Sun: Part Shade - full shade

Height: 2-3 feet tall

Blooms: White, September - October

Soil: Sand, loam

Moisture: Moist to dry

The elegant, pure-white flowers of White Wood Aster are small but plentiful and really stand out in the shade. It is a threatened species in Ontario, only being found naturally in a few locations. It is most often found in dry deciduous forests that are dominated by Sugar maple and American beech.

It spreads by rhizomes and seeds, making it a great choice to cover larger spaces, even in dry shade! It can handle shallow rocky soil too.

Pair White Wood Aster with other forest floor species such as Wild Columbine, Virginia Waterleaf or Wild Ginger. It is naturally found with other shade loving asters such as Heartleaf Aster or Large-leaf Aster. Grows well under Walnut trees.

Heath Aster (Symphyotrichum ericoides)

Sun: Full sun - light shade

Height: 1-2 feet tall

Blooms: White, August - October

Soil: Sand, loam

Moisture: Dry - Average 

Where Swamp Aster is the answer for the wettest of soils, Heath Aster is the answer to the driest of soils! It is naturally found growing in meadows, prairies, alvars and dunes so you know it’s drought tolerant. It loves sandy, rocky and gravelly soil but will do well in most gardens with average well-drained soil in full sun, but doesnt like competition from taller plants.

This is a very compact, low growing aster with profuse white flowers. It spreads slowly via rhizomes and seeds. They look great planted in clumps where the mass of conical flower clusters draw in your eyes. Great for rock gardens and borders where low growing, drought tolerant plants are desired. 

Plant it with Skyblue aster or short grasses such as Sideoats Grama or Little Bluestem.

Heart-leaf Aster (Symphyotrichum cordifolium)

Sun: Part Shade - full shade

Height: 2-3 feet tall

Blooms: lavender to light blue, September - October

Soil: Sand, loam, clay

Moisture: Medium to dry

Heart-leaf Aster, known as naskosi'icus by the Anishinaabe, grows in deciduous forests, and forest edges (even along gravelly trails). It will even grow in meadows granted the surrounding vegetation provides it with some shade.

Heart-leaf Aster is one of the latest blooming asters in Ontario. You can enjoy the light blue flowers through fall into early November! This makes it particularly important for late-season pollinators as they prepare for winter. It spreads slowly by rhizomes and lightly self-seeds in the garden.

A winning combination is Heart-leaf Aster, Bluestem Goldenrod and Bottlebrush Grass. It grows well with most other forest floor species. Grows well under Walnut trees.

Smooth Blue Aster (Symphyotrichum laeve)

Sun: Full sun - light shade

Height: 4 feet tall

Blooms: lavender to light blue, September - October

Soil: Sand, loam, clay

Moisture: Dry to Medium

Smooth Blue Aster has very frost hardy flowers, often blooming into early November! It maintains an upright, bushy form and the lavender/blue flowers bloom in profusion along the stem.

This is a good choice for boulevard gardens due to it’s upright form, salt tolerance and ability to survive drought.

It is easy to identify this aster as it has smooth, blue/green leaves. Due to it’s late blooming habit(even for an aster), Smooth Blue Aster is an important food source for late season pollinators especially bumblebees. The smooth leaves are eaten by rabbits and deer so consider giving them some protection.

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