best perennials for illinois

13 Best Perennials For Illinois Gardens and Landscapes

Illinois is ideal for growing perennials that add beauty to the gardens considering its USDA hardiness zones. Each of them has a different blooming period, offering you an endless charm of showy flowers through all seasons.

Nonetheless, picking beautiful perennials can be tricky since they have different characteristics that you need to consider. But, don’t worry! We have compiled the best perennials for Illinois to help you find out the most suitable plant for your perennial gardens and landscapes 

Not only you can enjoy their beauty, but also attract bees, butterflies, and wildlife in general to your home. Also, we add a quick guide to give you an initial insight into each plant. Hence, you’re not too blind to start planting them. Without any further ado, let’s get into the list!

1. Aromatic Aster (Symphyotrichum oblongifolius)

If you are looking for bushy flower beds, then Aromatic Aster is an ideal option for you. It is a clump-forming perennial that will pamper you with exquisite purple daisy-like flowers, creating a breathtaking view of any garden it inhabits. And as the name bears, the crushed flowers and foliage emit balsamic scents. Because of its beauty, Aromatic Aster attracts butterflies, bees, and moths to visit.

Aromatic Aster (Symphyotrichum oblongifolius)
Aromatic Aster (Symphyotrichum oblongifolius)

Moreover, cultivating aromatic aster is indeed relatively easy. It is one of the low-maintenance perennials that thrive in full sun and dry soil, though it tolerates moist soil as long as it is well-drained. Considering its habitat, Aromatic Aster will be greatly grown in rock gardens.

2. Black Snakeroot (Actaea racemosa)

Bearing long clusters of tiny fluffy white flowers covering long stems tips makes Black Snakeroot unique compared to other perennials. Seedheads are also seen adorning the ends of the sets of beautiful flowers.

Not only the flowers but the green-toothed leaves are also fascinating. Since it can grow to more than six feet tall, this rhizomatous perennial will add a vivid vertical statement to your garden.

Black Snakeroot (Actaea racemosa)
Black Snakeroot (Actaea racemosa)

As shade-loving plants, Black Snakeroot thrives in the partial to the full shade garden. Nonetheless, it still needs about 2-3 hours of morning sun exposure to allow flowering. Furthermore, this perennial favors moist soil, humus-rich, and moderately acidic to grow. You need to watch out for leaves spots in terms of diseases.

3. Blue Giant Hyssop (Agastache foeniculum)

Similar to the previous species, Blue Giant Hyssop is a vertical growing perennial with attractive spikes of lavender flowers that beautifully blooms from early summer to early fall.

In addition, it features attractive foliage that is commonly processed into jellies and herbal tea, thanks to the licorice-like scents. Knowing all these wonderful qualities, no wonder this deer-resistant perennial is famous among plant lovers and gardeners.

Blue Giant Hyssop (Agastache foeniculum)
Blue Giant Hyssop (Agastache foeniculum)

You will not make your hands full if you want to plant Blue Giant Hyssop. Since it can grow well in full sun to partial shade, the choice of planting location becomes wider. It also prefers sandy, moist, but well-drained soil. As an easy-to-grow perennial with stunning features, Blue Giant Hyssop is an excellent choice to grow in butterfly gardens, cottage gardens, and even cut flowers!

4. Blue Wild Indigo (Baptisia australis)

Among all low-maintenance perennials for Illinois, Blue Wild Indigo is worth consideration because of its effortlessly stunning purple-blue flowers. Not to mention its charming green foliage that stands well all seasons before laying low on the ground in the winter.

Blue Wild Indigo (Baptisia australis)
Blue Wild Indigo (Baptisia australis)

To create a wonderful landscape, you will need some growing conditions to ensure Blue Wild Indigo grows happily. This hardy native perennial prefers moist, well-drained soil or clays with acidic to circumneutral pH, though it also tolerates lime.

It also favors full sun; thus, it is important to plant them where they can have ideal lighting exposure. Unfortunately, this plant is toxic, although there is no specific evidence that it can be fatal to humans.

5. Common Milkweed (Asclepias syriaca)

Despite being in the same family as Butterfly Weed, Common Milkweed, or Asclepias syriaca does not feature striking orange flowers. Instead, it has large ball-shaped clusters of purplish flowers with pleasant scents. The fragrance attracts butterflies, while monarch butterfly larvae enjoy the foliage – the mere source of food for them.

Common Milkweed (Asclepias syriaca)
Common Milkweed (Asclepias syriaca)

Speaking of its growing conditions, it loves the sun and well-drained soil, but moist. It will grow well in medium to fine sandy, clay, rocky calcareous, and is also found in well-drained, loamy soils.

Besides grown as a beautiful perennial to enhance gardens and landscapes, Common Milkweed has cardiac glycoside whose digitalin is involved in treating heart disease. However, this perennial is poisonous in large quantities.

6. Coral Bells (Heuchera sanguinea)

Heuchera sanguinea or Coral Bells is one of the best perennials for Illinois gardens that will be perfect for dry areas. It bears upright stems with coral red, bell-shaped flowers hanging in narrow clusters from the upper parts of the stalks.

These enchanting flowers bloom exquisitely in mid-summer. Besides, Coral Bells plant is also popular for the heart-shaped, mounded foliage that offers greeneries to the garden. 

Coral Bells (Heuchera sanguinea)
Coral Bells (Heuchera sanguinea)

Furthermore, taking care of Coral Bells is not necessarily difficult. It needs shade in warmer climates but does well in full sun and part shade in colder areas. In addition, medium watering is required to maintain soil moisture, especially during summer. And to stimulate new growth, the old woody material should be discarded when this clump-forming perennial is about 3 to 4 years old.

7. Eastern Blue Star (Amsonia tabernaemontana var. salicifolia)

Another clump-forming perennial will happily greet you with star-shaped blue flower spikes in late spring to early summer.

They exquisitely bloom atop deep green leafy stems, adding ornamental features to their appearance. Meanwhile, all the leaves turn into the charming golden yellow shade in fall, creating an endless beauty through the seasons in between.

Eastern Blue Star (Amsonia tabernaemontana var. salicifolia)
Eastern Blue Star (Amsonia tabernaemontana var. salicifolia)

Safely saying, it is one of the best low-maintenance perennials for Illinois gardens. It thrives in average well-drained soil under full sun and partial shade. It is also drought-tolerant, clay tolerant, and deer resistant.

Its maintenance only includes pruning a third to a half of the plant after flowering to promote bushy growth, mainly when Eastern Blue Star has grown in the shade. No pruning is needed if it is planted in a sunny spot.

8. Hardy Hibiscus (Hibiscus moscheutos)

Like its namesake, Hardy Hibiscus is among hardy perennials that produce dazzling five-petaled creamy white flowers with magenta to deep purple shade at the base.

However, some other cultivars highlight showy flowers with pink and purplish hues. In addition, each flower carries protruding yellow stamen, creating impressive color contrast.

Hardy Hibiscus (Hibiscus moscheutos)
Hardy Hibiscus (Hibiscus moscheutos)

Despite loving average, medium to wet soil, this woody perennial fairly tolerates drought once established. Besides, it amazingly also copes well with heat and humidity at the same time.

Moreover, Hardy Hibiscus performs best under the full sun since the flowers produce in abundant compared to those grown in the shade. Adding fertilizer is necessary for the growing stages to ensure this plant grows as favored.

9. Orange Day Lily (Hemerocallis fulva)

No wonder Orange Day Lily is called a ‘perfect perennial’ knowing it has many excellent qualities that are impossible to resist.

This clump-forming perennial bears six petals of striking orange flowers with dark green foliage as the background, making a remarkable combination in one plant. Its flowering stalks grow 3-6 feet tall, allowing you to have fantastic garden borders.

Orange Day Lily (Hemerocallis fulva)
Orange Day Lily (Hemerocallis fulva)

Aside from showy flowers, Orange Day Lily belongs to low-maintenance perennials that is heat and drought-tolerant and grow in most hardiness zones. It also withstands summer humidity well. In addition, this sun-loving perennial favors fertile, loamy soil with mesic conditions. The ideal time to plant Orange Day Lily is in early spring or early fall.

10. Prairie Coreopsis (Coreopsis palmata)

Even though it has a similar appearance to Sunflowers, Prairie Coreopsis still belongs to the same family as Aromatic Aster. During the bloom time, it grows lovely daisy-like yellow flowers with a brownish disk on each. The green leaves in the late spring to mid-summer will turn yellow-red, enhancing the perfection the plant already has.

Prairie Coreopsis (Coreopsis palmata)
Prairie Coreopsis (Coreopsis palmata),(Image credit: ali eminov,justin meissen/Flickr)

Before the growing season, you can start to prepare the planting requirements of this showy perennial, including soil conditions and pH, light levels, and watering frequency. It grows best in full sun with dry to medium moisture and well-drained soils.

However, it also thrives in poor, rocky soils. As an easy-growing plant, Prairie Coreopsis is heat and drought-tolerant and also deer resistant. Moreover, this perennial will do great in prairies, wildflower, and cottage gardens like its name.

11. Prairie Onion (Allium stellatum)

Other than Prairie Onion, Allium stellatum is also known as Autumn Onion. It is a wild onion species native to North America that will stun you with its smashing bulbs of white-purple flowers with solid green leaves.

Not to mention its erect pale yellow stamens, which add to the elegance of this perennial. Interestingly, the flowers bloom all year, providing an exciting year-round landscape.

Prairie Onion (Allium stellatum)
Prairie Onion (Allium stellatum)

Regarding its planting requirements, Prairie Onion does best in part or light shade areas. Thus, a shade garden may perfectly fit this native plant. For the soil, make sure you prepare moist, mesic to dry, rocky soils if you want them to grow well. However, as it may spread aggressively in warmer climates, performing deadhead to avoid unwanted seedlings is necessary.

12. Purple Coneflower (Echinacea purpurea)

Echinacea purpurea, or Purple Coneflower, is extremely popular for its health properties and is commonly utilized as herbal tea to strengthen the immune.

In addition to its beneficial aspects, this perennial is well-known for the alluring purple and pink flowers with gracefully dropping petals, showing off its long-lasting beauty from mid-spring to early fall. These flowers are attractive to pollinators, while birds are happy to eat the seeds from the brownish disks.

Purple Coneflower (Echinacea purpurea)
Purple Coneflower (Echinacea purpurea)

With its spectacular qualities, it is no doubt that people are interested in growing Purple Coneflower in their gardens. This native perennial is adaptive to various soil types yet prefers dry, well-drained, and rich soil under the sun or partial shade. In some hardiness zone, it favors moist, loamy soil. Besides its beautiful flowers, Echinacea purpurea is also cultivated for research materials.

13. Russian Sage (Perovskia atriplicifolia)

It is one of the hardy plants you will need to consider because of its long-blooming season. Russian Sage or Perovskia atriplicifolia is a deciduous perennial, carrying long terminal panicles of lavender to petite blue flowers that add exquisite shade to any garden it is planted. The white stalks grow fragrant green silvery foliage that is in tune with the flowers’ color.

Russian Sage (Perovskia atriplicifolia)
Russian Sage (Perovskia atriplicifolia)

Suppose you are about to plant Russian Sage. In that case, you need to save a full sun area with dry to medium, well-drained soil. It is a drought-tolerant perennial that copes well in dry sites once established.

This plant is rabbit and deer resistant, also salt-tolerant, making it way easier to take care of. In addition, cutting back the plant to the ground in late winter to early spring is necessary for maintenance.

FAQ (Frequently Asked Questions)

What perennials grow all year in Illinois?

From our extensive list of the best perennials for Illinois gardens and landscapes, Prairie Onion (Allium stellatum) is a beautiful perennial that showcases its beauty through year-round seasons. 

It has exquisite bulbs of white-purple flowers with solid green leaves. Not to mention its erect pale yellow stamens, which add to the elegance of this perennial.

What perennial flower blooms all summer in Illinois?

Several perennials bloom all summer in Illinois, depending on the broad range of hardiness zones.

Some of them belong to our fantastic collection of the best perennials for Illinois gardens and landscapes, such as Blue Giant Hyssop (Agastache foeniculum), Black Snakeroot (Actaea racemosa), Prairie Onion (Allium stellatum), and Purple Coneflower (Echinacea purpurea).

Each of them has distinctive characteristics that are too unfortunate to resist. But one thing is for sure, they will add colorful summer shade to your Illinois gardens and landscapes.

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