10 Perennial Plants That Can Take the Heat

While I love summer blooms, sometimes the heat and humidity give me a reason to enjoy these flowers through my living room and kitchen windows.  No one wants to have heat stroke while trying to water their plants back to life.  The trees around our home are not yet mature, so our landscape plants must endure the blistering sun without the reprieve of shade, save for a sliver of jealously-guarded coolness on the north side of our house.  I have assigned this area to the hydrangeas and hostas, and all other plants must be fighters in this middle Tennessee zone 7 that can sometimes feel like the surface of the sun.  I am here to assure you that there are some wonderful plants out there that not only survive this heat, but thrive in it - and bonus, many of them don't like fertilizer either so they are low-maintenance all around.  As always, check specific varieties for your gardening zone.

1. Russian Sage - We will start with one of my very favorites.  I noticed and loved this little shrub from before I was a gardener.  It comes in varying hues of blue and violet and is tough, drought-resistant, deer-resistant, and just generally low-maintenance.  The silver-green foliage is topped with tubular blooms from mid-summer to fall.  They are typically hardy in zones 4-9 and are excellent as a hedge or en masse planting.  I personally have both the Denim 'N Lace and the Blue Jean Baby varieties and have had zero problems with them in the years I have grown them.

2. Lavender - The distinctive look and divine scent of lavender make this plant a no-brainer in xeriscaping.  It is hardy and does not need or like heavily amended soil.  Except for pruning in late winter and again after blooms dry, I do very little with this plant.  Is is my number one pollinator magnet, even over borage, butterfly bush, or agastache.  Of course, besides the medicinal qualities of lavender, it is also just pleasant to use dried, such as in potpourri or sachets in drawers.  

3. Hummingbird Mint - Also known as agastache or hyssop, this pollinator-friendly perennial gets top marks for variety.  It comes in multiple colors and is easy to grow from seed.  I love the purple, blue, and pink, but there are also orange, red, and white variations.  Despite its lovely smell and ability to be used as a tea, it is not a favorite of deer or rabbits.  It also prefers lean soil and can come back for many years as well as gently self-sow if allowed.  

4. Catmint - Another admirable entry from the mint family that also prefers dryer, leaner soils.  It is long-blooming and resistant to deer as well, with lovely gray-green foliage that typically stays neat and tidy, although size or age can lead to "flopping over" which can be addressed with pruning.  This is a lovely accent flower, especially when paired with pinks or yellows and hides the bare legs of roses well.

5. Artemisia - Also known as wormwood or mugwort, artemisia is a varied genus that consists of shrubs and herbaceous plants.  They are mostly known for their foliage, although some do have flowers.  Typically boasting that cooling silver color, some to the point of looking white, they are able to set off all other blooms around them without fading into the background themselves. Wormwood has been used for centuries as a medicinal plant as well and is known to thrive and spread beautifully even in 100-degree heat.  I personally own both the Powis Castle variety and the Silver Mound, and although both are quite different, I love both and am always looking for places to put more of them.  Silver Mound is especially known to resist the heat and is a beautiful workhorse as an edging.

6. Sedum - Sedums are a fun succulent, because they come in all shapes, sizes, and colors.   There is at least one type of sedum for everyone. It is very difficult to kill them unless you are actively trying.  It loves the heat and the drought, and in fact, needs as much sun as possible to prevent "legginess".  This is another plant not favored by deer.  It requires very little, including pruning, which can be limited to old growth in early spring if necessary.   

7.Yucca - Ok, full disclosure, I am not the biggest fan of yucca plants.  But when I say they are drought-tolerant, believe me that they will try to set a taproot down to China and survive whatever your summer throws at them.  Some yuccas are beautiful, but I have memories of trying to dig one out of my first front yard, and I could not kill or dig up this plant on my own.  It continued to reappear for years.  I am not sure if all yucca plants are this tenacious, but I did not want to plant more and find out.  I wanted to plant some peonies, but someone had previously put in yucca plants.  Eventually, I realized it was just easier to move.  Ok, so I didn't move because of the yucca, but if you know for a fact you will want a yucca to be forever in the spot you plant it, go for it.  Otherwise, I would put it in a container.  And then set that container on concrete. 

8.Coreopsis - Also known as tickseed, coreopsis is a member of the sunflower family.  Despite their delicate look, they can handle the baking heat and still pump out flowers all summer long. They can handle long periods of drought and require very little care.  They may be divided after a couple years just to keep the vigor going. 

9. Verbena - Perennial verbena, sometimes called vervain, is a regular in xeriscaping.  They bring pollinators in droves and can gently self-sow if allowed.  There are different types of perennial verbena, but all seem to do well in drought and heat.  I have tall verbena (V. bonariensis), and it has stayed in various stages of flowering all summer.  Despite record-breaking winds, it also remains upright and lends an airy, open feeling to some of the heavier shrubs surrounding it.  Tuberous verbena, or slender vervain, is also known to be incredibly tolerant of heat and humidity.

10. Black-eyed Susan - Another high performer in mid to late summer, Black-eyed Susan can and will welcomely self-sow without being aggressive.  Every year, I am delighted to see where they will pop up in their orange-yellow glory.  Even as some of the mid-summer flowers are fading, these continue to go strong and lend some much-needed color in the heat.  We have these growing wild in our country pastures, but there are also dozens of different varieties bred for different colors, markings, or heights. 

Although there are many other plants that do well in this heat, this is a great starting point whether you want to try a new shrub, succulent, or herbaceous plant.  I have grown every one of these (ok, the yucca was against my will), and they all have performed reliably for me for years.  There is a reason all these are relatively easy to find at any local nursery.  They have passed the test of time with many, many gardeners.  As summer begins to fade, we look forward to cooler temperatures and rainier days, but these heroes of the plant world will soldier on till first frost, helping to close the gap between heat and harvest.