Reliable Plants for Hot, Humid Summers

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Echinacea Cheyenne Spirit
Classic prairie perennials such as Echinacea 'Cheyenne Spirit' thrive in heat and humidity.

In the Midwest, we may not experience intense summer heat like Arizona or Florida but we sure have our days.  Here in Zeeland, Michigan, this summer was one of the hottest on record and the humidity seemed to persist all summer long.  Some perennials just couldn't take the heat and went dormant early.  But others seemed to thrive in the intense heat, looking just as beautiful at 70°F as they did at 90°F. 

We thought this would be helpful information to share, so at the end of August this year, we recorded which plants in our expansive display gardens were still looking great despite the heat.  We recorded the names of about 240 varieties of hardy perennials and temperennials which we considered to be heat and humidity tolerant plants.  Though there were a few surprises such as ferns, many of the plants that made the list are classic heat tolerant perennials like Echinacea and Gaillardia. 

Read the full list of heat and humidity tolerant plants here.

It's important to remember that this list of heat and humidity tolerant plants was recorded in Michigan zone 5, so gardeners in warmer parts of the country may have different experiences.  Also, not every plant we offer (over 1,000 varieties) was included in our trials so you may not see every variety in a specific genus listed.  But since seemingly little has been written about the heat and humidity tolerance of perennials in the Midwest, this is a good place to start.  

Summer 2010 was one of the very hottest on record in Michigan, with high temperatures 3.32°F above average.  In fact, every month since November 2009 has been warmer than average in Michigan.  25% of the days this summer had high temperatures above 85°F with 9 days over 90°F.  Thankfully, overall rainfall was also up this year measuring in at .48 inches above normal so we did not have drought to contend with on top of the heat.  Michiganders breathed a collective sigh of relief when cooler temperatures finally settled in at the end of September.

Those of you who live in warmer climates than Michigan probably laugh at our concept of heat.  Surely, people in some parts of the country would relish in having just 9 days over 90°F!  So to read about more formal trials of heat and humidity tolerance from the south, check out the Athens Select™ website.  Founded by Dr. Allan Armitage in 1998, Athens Select™ is a collection of heat and humidity tolerant plants selected from trials at the University of Georgia.  New varieties are added to the program annually.

Colocasia Thailand Giant 
Drought tolerant plants are often heat tolerant as well, though there are exceptions such as this tropical Colocasia 'Thailand Giant' which requires consistent moisture.

The average Midwest gardener who experiences hot, humid summers should be able to grow the plants on our list with good success.  It's important to keep in mind that this is not a list of drought  tolerant plants, though some of them can certainly survive with little water.  Heat and drought tolerance do not always go hand in hand.  Many tropical plants such as Colocasia are very heat and humidity tolerant but require a consistent supply of moisture to thrive.  Find a list of drought tolerant plants here

Selecting the right plant for the right place just makes sense.  If you garden in an area with hot, humid summers, start with this list of heat and humidity tolerant plants and watch your garden thrive!