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Spring bloom as of Wednesday, May 13
It’s time to enjoy all the shades of green that summer brings, along with the flowers of gardens and prairies to be seen throughout the season at The Morton Arboretum.
This is the final Spring Bloom Report for 2026. Weather kept many plants’ bloom times brief this year, with alternating warm and cool spells, heavy rains, and frosts. Yet there are still flowers to enjoy as you plan a summer full of visits to the Arboretum for lively events, blooming gardens, carefree play, and the beauty of nature.
Visitor Center area, including parking lot P-1, Administration and Research Center and The Grand Garden: Both blue and white periwinkle are still in flower, along with white snowdrop anemones, and white-flowering cotoneaster.Lavender-pink Korean lilacs are still blooming, along with Winter Beauty blood-twigged dogwood. Look for blue flowers including pale blue Arkansas bluestar, dark blue salvia, and dark blue-purple false indigo.
On the East Side
Northern Illinois and Midwest Collections (parking lot P-2): Trees and shrubs in bloom include white-flowered nannyberry viburnum, chokeberry, and alternate-leaved dogwood. Catkins, or dangling male flowers, can be seen on many kinds of oak trees.
Frost Hill and Conifer Collection (parking lot P-3): The view from Frost Hill across the river valley is beautifully green. Three alternate-leaved dogwoods add bloom and color.
Crabapple Lake (parking lot P-4): A few chokeberries and mountain-ash trees are still in flower amid the green.
East Woods (parking lots P-8 through P-16): The woodland wildflower season is nearly done. The few flowers still in bloom include blue woodland phlox; pink wild geranium; green and maroon Jack-in-the pulpit; and white May-apples.
Maple Collection and Beech Collection (parking lot P-14): Look for white to lavender shooting stars in bloom among the nearby prairie grasses.
Eastern North America Collection and Temperate Asia Collection (parking lot P-16 to parking lot P-18): White flowers of black-locust trees are in full bloom.
On the West Side
Founder’s Grove (parking lot P-20): A few last blue woodland phlox and pink wild geranium blooms can still be seen.
Thornhill Education Center, Fragrance Garden, Joy Path (parking lot P-21): Enjoy the colorful flowers in these all-season gardens.
Following the West Side Main Route
Daffodil Glade (parking lots P-22 and P-23): A few blue woodland phlox and pink wild geraniums are still in bloom amid the grass.
Sterling Pond (parking lot P-24): There are still a few blooms of blue woodland phlox and pink wild geranium.
Schulenberg Prairie (parking lot P-25): In the Schulenberg Prairie, grasses are green and summer blooms are on the way. Prairie flowers will bloom among the grasses all summer long.
Following the West Side Alternate Route
Sargent’s Glade (parking lot P-26): There are scattered blue woodland phlox and pink wild geraniums.
Lake Marmo (parking lots P-27 and P-28): Great white trillium can still be seen on the south side of the lake, along with a few blue woodland phlox and pink wild geraniums.
Summer is arriving. Visit often to enjoy the cool shade of majestic trees at The Morton Arboretum!
Featured Blooms
Buckeyes
In May, Buckeye trees and shrubs bloom with a diverse display of flowers that can be white, red, yellow, pink, or purple.
Lilac
Lilac is a hardy shrub that thrives with little care, known for fragrant May-blooming flowers in shades of purple, magenta, and pink.
Nannyberry
Nannyberry viburnum is a large shrub or small tree that blooms with clusters of small, creamy white flowers in spring. In fall, it produces berry-like fruits that are an attractive food source for birds.
Periwinkle
Periwinkle is a mat-forming ground cover plant with dark green foliage and purple flowers.
Wild geranium
A woodland wildflower native to Illinois and the Chicago region, wild geranium blooms with pink to lavender flowers in late spring.
Woodland phlox
Woodland phlox is a native wildflower known for its delicate, lavender-blue to white flowers.
About the Spring Bloom Report
The Spring Bloom Report is written by The Morton Arboretum’s manager of plant records, Ed Hedborn. It is typically published on Wednesdays throughout the spring to help guests plan their weekend visits. The Arboretum also publishes a weekly Fall Color Report in fall.