7 Flowers to Outlast the Summer Heat

Avid gardeners never give up, even when storms, heat, humidity, or drought threaten to bring summer’s blooms to end. To discover which flowering plants do best long into summer and even to the first frost, we asked Alan Branhagen, Director of Operations at the Minnesota Landscape Arboretum, for his top picks. Branhagen is also the author of Native Plants of the Midwest: A Comprehensive Guide to the Best 500 Species for the Garden and The Gardener’s Butterfly Book.

The first three are plants native to Minnesota.

1. Anise hyssop. Not only do the purple flowers of this striking plant bloom long into September, says Branhagen, but the flowers are edible, “like a little piece of licorice,” can be used to make tea, are rich in nectar for pollinators, and produce seed that goldfinches love.

2. Oxeye or false sunflower. This plant will also set flowers until frost, which will attract pollinators. “There are a few cultivars on the market, including Tuscan Sun, which is actually cultivated from a wild plant in Wisconsin.”

3. Swamp or rose milkweed. One of ever-popular milkweeds, which is manna to monarchs, this native plant does best in wet soils, but will do just fine in average soils. “Don’t forget to put your nose to it, to take in the sweet candy corn fragrance,” says Branhagen.

4. Walker’s low cat mint. A perennial favorite, with many varieties, it’s Walker’s low that has the “real flower power,” says Branhagen. “It will get four feet in diameter and is a real draw for hummingbirds.”

5. Bonariensis or verbena. A self-sowing annual (as is Walker’s low cat mint) originally from Argentina. “The little flowers grow up on tall stems, and because it’s one of the best plants for butterflies, the stalks bring them up closer to eye level,” says Branhagen.


6. Dragon’s wings begonia. “Nothing beats this plant in the shade, with its rose and cherry pink flowers,” says Branhagen. “We have it huge hanging baskets at the Arboretum, which really shows off the angular shaped wing-like leaves.”

7. Canna: These popular plants vary in size from very small to 10 feet tall, and come in yellow, orange, red, and pink. A tropical plant, they’re heat and humidity tolerant. “You can dig up the corms after frost, put them in peat moss in the basement, and they’re easy to bring over to the next year,” says Branhagen.

Alan Branhagen, Director of Operations

Alan Branhagen is Director of Operations at the Minnesota Landscape Arboretum where he supervises capital improvements, horticulture and natural resources, plant curation, facilities, and information technology. For over 20 years, he was Director of Horticulture at Powell Gardens, Kansas City’s Botanical Garden, and prior to that he served as Deputy Director of Resource Development for the Winnebago County Forest Preserve District in Rockford, Illinois.  Alan received his Bachelor of Landscape Architecture from Iowa State University and a Master of Landscape Architecture from Louisiana State University with emphasis on planning, plants and design with nature. He is the author of Native Plants of the Midwest: A Comprehensive Guide to the Best 500 Species for the Garden and The Gardener’s Butterfly Book. Beyond public garden management, Alan is an all-around plantsman and naturalist, specializing in botany, birds and butterflies. He is currently creating and restoring a three-acre prairie and woodland garden around his home overlooking the Minnesota River Valley in Chaska.

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