Heat Loving Perennials

When it comes to summer, you want to have as many heat loving perennials as possible. At least, here in the Central Great Plains, where daytime temps can reach 110 degrees F and nighttime temps may stay in the 80, we do. Of all the 25 heat loving perennials mentioned below, I have 23 in my gardens at home. You do not need to stack the deck quite so thick as that, but choosing at least 10 would be a go way to go.

By adding more heat loving perennials to your garden, you can almost guarantee having a ton of blooms in the summer when the heat is turned up. I like to have a succession of flowering perennials in my gardens. This means that you will have flowers blooming back to back, if not continuously. What you have to worry about is over doing it. Sometimes, you can plant too many perennials! I really overdid it in my Sunny Cottage Garden., where I ended up with more than 60 species of plants in 250 square foot bed.

Where to Put Heat Loving Perennials?

When planting your heat loving perennials, be sure to always site things in the correct location. These plants love full sun, but most are also tolerant of some light shade conditions too. Most of these perennials will fit into a variety of garden styles, although some styles may be too strict for some of them. For example, I do not think that the majority of these plants would fit a Japanese style garden, where there are a lot of evergreens and subtle colors.

The different garden styles where most of these heat loving perennials fit include the following:

• Cottage
• Formal
• Mediterranean
• Naturalistic
• Meadow
• Pollinator/Butterfly
• English
• Colorado/Mountain

All 25 of these flowers are sun lovers and will add a riot of colors to the garden. If you choosing to group in masses, you will get a more dramatic effect, as long as you pick enough of them to fill the garden. I prefer to plant close together, making sure to have plants overlap each other a bit. By doing this, I lower the risk for a weed patch to develop.

Nonnative Heat Loving Perennials

As usual, I am splitting the perennials up by native or nonnative status. I think this helps for those of you who are wanting to be more native oriented, as now 1 in 4 customers will choose natives of nonnatives. But there will still be a lot of good choices here, for the few nonnatives are mostly from the Mediterranean region. Here in the Central Great Plains, we get our humid heat starting in June and continuing until late August. The worst period for heat is from late July to August, because it usually dries up too. In 2023, we got a good rain at the beginning of July, and no significant rain again until September, plus many days in 90s.

Catmint – Nepeta species

There are a lot more catmints available than there were when I first started working in landscaping. Back in the early 2000s, ‘Walker’s Low’ was the only cultivar available, it it gets big! But now, we have more modest and tidy cultivars like ‘Purrsian Blue’ and ‘Cat’s Pajamas’. Plus many more. My favorite of the new catmints is called ‘Whispurr Pink’, an upright variety, growing 2 to 3 feet tall and wide. Catmint is very tough, and will keep blooming from May until September, but it will improve with a haircut in mid July. It has no major pest problems, and is a good choice where deer are a problem.

Catmint makes a great border plant for the garden. It fits best into formal, cottage, Mediterranean, and English style gardens. I would not use it in a Meadow garden. Pollinators include bees and bumblebees, butterflies, and some wasps. In the fall, cut the plant to the ground and you are done with maintenance. The best cultivars are below.

Cultivars

• Whispurr Pink – pink flowers on 2 to 3 feet tall and wide plants.
• Whispurr Blue – has purple flowers with a mounded habit. It grows 2 to 3 feet tall and wide.
• Cat’s Pajamas – has dark purple flowers on a tidy plant, growing 14 inches tall by 18 inches wide.
• Purrsian Blue – grows 18 inches tall by 30 inches wide with lavender flowers.
• Cat’s Meow – has lavender flowers on 20 inch tall by 3 feet wide plants.
• Chartreuse on the Loose – is a new cultivar with chartreuse colored leaves and purple flowers. It grows 1 foot tall by 2 feet wide.

Butterfly Bush – Buddleia species

While many people would not called butterfly bush a perennial, but a shrub, here in the Central Great Plains, at least, it acts like a perennial. Typically, butterfly bush dies back to the ground or at least lower branches each winter. Because of the severity of our winter weather, this is almost always the occurrence. But butterfly bushes are heat loving perennials.

Depending on the cultivar you choose, they can grow between 1 and 12 feet tall and 2 and 12 feet wide. One of my favorite cultivars is called ‘Honeycomb’, an older variety which has bright yellow flowers on a 10 foot tall and wide plant. But many of the new cultivars, which are also sterile, are smaller. Sterile means that they do not produce any viable or growable seed even after pollination.

I like to have butterfly bush as a stopping spot in the garden to photograph butterflies, though I would make sure not to use is solely. Beyond attracting in butterflies, it has no wildlife value, and it is not a host plant for anything. It has no pests and diseases either. Cut butterfly bush to the ground in later fall or early spring. It should bloom continuously from July to September.

Cultivars

• Miss Molly – grows 4 to 5 feet tall and wide and has magenta flowers.
• Pugster Pinker – grows 2 feet tall and wide with dark pink flowers.
• Black Knight – is an old favorite that grows 6 feet tall and wide with dark purple flowers.
• Pugster Amethyst – grows 2 feet tall and wide with lavender flowers.
• Honeycomb – has yellow flowers and grows 10 feet tall and wide.

Ornamental Onion – Allium species and hybrids

I cannot say enough about ornamental onions, as you probably know. It is one of the best heat loving perennials there is. Not only does it bloom in the heat and provide for a lot of pollinators, it has a tidy habit and can be used in a variety of locations. I like to use best as a border plant around the edges of bigger garden beds in my Sunny Cottage Garden. There are a number of cultivars for this deer and rabbit proof plant.

Cultivars

• Millenium – grows 1 foot tall and wide with pink flowers.
• Mongolian Gem – grows 1 to 2 feet tall by 1 foot wide with white flowers.
• Lavender Bubbles – grows 1 foot and wide with dark purple flowers.
• Bubble Bath – has larger pale lavender flowers on 16 inch tall and wide plants.
• Medusa – has smaller pink flowerheads above twisty foliage

Daylilies – Hemerocallis hybrids

There is a lot going for daylilies. With several thousand cultivars available across a wide range of places, it can be difficult to choose the right ones. I used to hate them, before I really got to know them. The problem really, is the over planting of one cultivar, Stella D’Oro, a cherry orange-yellow flower on a short plant, which happens to get aphids a lot. But there are so many other cultivars. There is even an American Daylily Society!

In the heat of the summer, daylilies are blooming. If you choose several cultivars, you could potentially have blooms from May to September. And they love the heat! They have grass-like foliage which withstands heat and humidity well in the Central Great Plains. I like to use them in beds around my Sunny Cottage Garden, but they also work well in Mediterranean, English, and formal gardens. They have few if any problems, though deer will browse them.

Favorite Few Cultivars

• Prairie Wildfire – is a deep, burgundy red with a bright yellow center. It grows 2 feet tall and wide.
• Storm Shelter – has ruffled petals that are pink, then purple, then yellow. It grows 2 feet tall and wide.
• Kansas Kitten – is dark pink with a dark purple band and a yellow center on 2 foot tall and wide plants.
• Lake of Fire – has very ruffled petals which are apricot-orange with magenta bands on 2 foot tall and wide plants.

Red Hot Poker – Kniphofia hybrids

Of the more interesting flowers is the red hot poker. The flowers come up on a central stalk and hang down as they bloom. Its a wonder that they get pollinated at all, but hummingbirds are attracted to the tubular flowers. Recently, breeding programs have worked to get several new colors, ranging from yellow to orange to red, and for longer bloom periods as well.

The foliage looks resembles those of pineapples or v-shaped yucca leaves. The are stiff and narrow, and are ornamental themselves in the garden. As for heat, they are tough! Native to South Africa, they are the epitome of toughness. I have an old variety in my garden, which I planted there 9 years ago, and it faithfully blooms and never shows any signs of stress. Deer and rabbits completely avoid the plant, though grasshoppers sometimes chew the foliage. Just remove the old foliage and flower stalks in late winter for upkeep.

Cultivars

• Rockets Red Glare – is one of the newest cultivars with two tones of flower colors, red and cream on the same flower stalk. It grows 3 feet tall by 2 feet wide.
• Orange Blaze – grows 3 feet tall by 2 feet wide with screaming orange flower color.
• Gold Rush – has bright yellow flowers and grows 4 to 5 feet tall by 3 feet wide.

Meadow Sage – Salvia hybrids

While there are certainly some native sages, these are hybrids of European and Asian species. Often just called salvia or garden salvia, there are a host of cultivars to choose from. I prefer mostly the Proven Winners varieties, with a few additions. But there are hundreds to choose from. Meadow sage grows in tight clump, rarely seeding out, and forms a rosette of leaves over which prodigious flowers arise. The flowers bloom from May to September, and appreciate a haircut in July for renewed vigor.

Because of its mint family connections, sages have strong odors which rabbits and deer avoid. For care and upkeep, just prune down the old foliage and flowers in November, done!

Cultivars

• Crystal Blue – has pale blue flowers on plants growing 1 to 2 feet tall and wide.
• Back to the Fuschia – has fuschia pink flowers on 2 foot tall and wide plants.
• Azure Snow – has purple and white flowers, perfect for a K-State fan! The plants grow 1.5 feet tall and wide.
• Blue By You – has purple-blue flowers on 1.5 foot tall and wide plants.
• Pink Profusion – has pink flowers on 1.5 foot tall and wide plants.
• Snow Kiss – has white flowers and grows 2 feet tall and wide.

Native Heat Loving Perennials

Among native plants in the Central Great Plains, almost anything from the prairie or savannah could be considered heat loving. That being said, there are some plants which do better than others either in extreme heat, or a combination of heat and drought together. These are the heat loving perennials considered below, which have various places in the garden. Most of these which I have, are either in my Sunny Cottage Garden or Meadow Garden areas.

I love to plant, promote, and plan with natives. They not only work well because of their tolerance and adaptability to our current and changeable weather patterns, but they also come in a wider range of cultivars than in the past, making them even more versatile. By using cultivars as well as the species, I can design garden beds based on color schemes with them.

Woolly Verbena – Verbena stricta

As far as I know, there are not yet any cultivars of this long-lived, heat lover. But that could change in an instant if someone besides me comes across the pink variations of the purple flower. I even went so far one year to dig up a plant from a Nebraska road ditch and add it to my perennial test plot in the Grimm’s Gardens arboretum. It thrived as long as the now defunct test plot did. But it has long since been mowed over. But I keep looing for more.

Woolly verbena grows 2 to 4 feet tall and 3 to 5 feet wide. The leaves are coarse and stiff and the flowers bloom in upright stalks. Butterflies flock to the flowers, which can be purple, pink, or even white ( I came across a white one at the Tallgrass National Prairie Preserve). It is best planted in the Meadow garden where grasses can keep it from reseeding too much.

Beebalm – Monarda species and cultivars

There are roughly 5 species of beebalm in the Central Great Plains regions, and some 20 species in North America. The plant grows in meadows and prairies primarily, and can grow 3 to 8 feet tall and spread into large clumps, depending on species. In cultivation, plant breeders have focused on shortening the plant and making it tidier for use in landscapes, often resulting in plants which get powdery mildew. In the wild, I have never seen powdery mildew on it.

Flower colors range from pink to red, and from purple to almost blue. Pollinators include hummingbirds, bumblebees, and other bees. It is a member of the mint family, and has a strong scent and taste, making it repellent to deer and rabbits. For upkeep, cut the stems to the ground in late winter or early spring.

Cultivars

• Pink Chenille – has bright pink flowers and grows on plants that get 1.5 feet tall and wide.
• Lavender Taffeta – has bright lavender colored flowers. The plants grow 1 to 2 feet tall and wide.
• Coral Reef – has bright magenta flowers on 2 to 3 foot tall and wide plants.

Culver’s Root – Veronicastrum virginicum

Another one of my favorite heat loving perennials, Culver’s root is an upright, wet or dry loving native. It is an excellent choice for butterfly or pollinator gardens. As it is able to take periods of standing water, then drought, it is a great choice for rain gardens. Culver’s root grows tall, 4 to 6 feet tall, and 3 feet wide in a nice clump. The flower spikes are white or purple, and attract a lot of wasps, bees, bumblebees, and some butterflies. It has few if any pests and no disease issues.

There is only one cultivar, ‘Fascination’, which has purple flowers instead of white. But I have not had luck with the cultivar, it has been spindly in the garden.

Butterfly Milkweed – Asclepias tuberosa

There are a lot of milkweeds which can stand the sun and heat, but butterfly milkweed is the best among them for the Central Great Plains. It blooms for a long time, from late May to August, and the orange blooms are hard to beat. And the amount of pollinators this plant attracts! If I had the time I would watch it for hours to see all that comes to the blossoms. Butterfly milkweed grows 1 to 3 feet tall and wide and older clumps form layered flower stems, giving the plant more depth as it ages.

Flowers are typically orange, but can also be red or yellow. The only cultivar, ‘Hello Yellow’ is a golden yellow color. Monarchs and a few moths feed on the foliage of course, and there are also oleander aphids which are problematic, but usually controlled with natural predators. No major diseases affect it. For maintenance, just remove the old stems in late winter.

Garden Phlox – Phlox paniculata

Of all the heat loving perennials on this list, garden phlox may be the one which prefers the most shade. Even though it does love the heat, it is found wild along the woodland edge. But there is no doubt as to its prowess; the summer flowers are immensely attractive to large swallowtail butterflies and long-tongued bees. Flower colors can be quite varied, though pink is the most common. There is also white, orange, lavender, red, and multi-colored cultivars available.

Garden phlox grows 2 to 5 feet tall and spreads by rhizomes to form a large clump or patch. It does suffer from powdery mildew in areas of high humidity and low wind, so put it in the open if possible. Just cut back the stems in late winter for cleanup.

Spike Blazingstar – Liatris spicata

Actually, all the blazingstars from around the Central Great Plains are heat loving perennials, but spike blazingstar is the most tidy and well-behaved. It grows 1 to 3 feet tall and wide in the garden, and the flowers can be pink or white. I like to plant both colors next to each other to get a more colorful effect. Blazingstars bloom in succession by species, and spike is the first to bloom, starting in early July.

Blazingstars are attractive to a wide range of bees, butterflies, and wasps, and various other pollinators as well. They have no problems with diseases. To maintain, just cut back the dead stems inch above ground in late winter. ‘Kobold’ is a pink flowered cultivar and ‘Alba; is a white flowered one.

Rattlesnake Master – Eryngium yuccafolium

One of my favorite heat loving perennials, it has excellent architectural flowerheads. The stalks are stiff and upright above the yucca-like foliage. White flower clusters arise off the steady stalks and are quite attractive, both in looks and to pollinators. The hollow stems are used by bees and wasps for their larvae in winter, so be sure to cut it back in late winter or remove the stems to a nearby brush pile. Rattlesnake master grows 3 to 5 feet all and wide, with no disease issues. It also grows well in ditches and is an excellent rain garden plant.

Mexican Hat – Ratibida columnifera

It almost seems to dainty in the garden to be a perennial. But the Mexican hat, which is a vase shaped plant, blooms profusely in late spring and summer, seeming to get better in the heat. It keeps on going too, even when many other perennials have petered out. I planted the yellow flowered variety in my Meadow Garden, and it reseeded into the red flowered variety!

Mexican hat grows 1 to 2 feet tall and wide and attracts bees and beetles to the flowers. It is fairly tidy and can be used in formal, cottage, and Mediterranean gardens, but do not put it where it would get wet feet for long. Plan to cut it back in late winter.

Mountain Mint – Pycnanthemum species

There are several species of mountain mints in our region, all of them blooming in midsummer. They are typically found in meadows and glades, but will grow in a variety of places. One of my favorite plants, the mountain mints are true mints, but without the aggressive spreading habit. If you need plants that attract beneficial insects, look no further, for they bring in a lot of parasitoid wasps, predatory beetles, and more.

Mountain mints spread slowly through rhizomes or by seeds, growing 1 to 4 feet tall. They have white flowers with tiny purple petals, and can be cut back in late winter or early spring. They have no diseases and they are deer and rabbit proof.

Ironweed – Vernonia species

Ironweeds are great heat loving perennials. And they are rarely beset upon by deer and other foragers. Even cows do not eat them in the pasture. Best planted in the meadow or pollinator garden, their bright purple flowers attract bees and butterflies. Western ironweed grows 4 to 5 feet tall and up to 3 feet wide in a clump. Ironweed ‘Iron Butterfly’ is a shorter variety which grows 2 to 3 feet tall and wide. Both are hardy and tough.

Wild Quinine – Parthenium integrifolium

The first time I came across this native was in the un-watered flower beds of the Jackson County Courthouse in Holton, KS. A friend who was the caretaker planted them knowing they would have to be tough and heat loving, for the whole property is a heat sink with concrete walks. The white flowers were attracting bees and butterflies in the native prairie garden. It grows 1 to 2 feet tall and wide.

Rudbeckia ‘American Gold Rush’ – Rudbeckia hybrid

While all the Rudbeckias are heat loving perennials, this newer cultivar is the best for landscapes. I added it to my Sunny Cottage Garden shortly after it came available in the nursery, and I have been impressed ever since. The problem with the old standard, ‘Goldsturm’, is that it gets Septoria Leaf Spot, a fungal disease which causes blackening of the stems, leaves, and flowers. ‘American Gold Rush’ not only blooms longer, but is completely resistant to Septoria.

American Gold Rush grows and blooms the first year, and gets 1 to 2 feet tall by 2 to 3 feet wide. It blooms on average, from June to October, and is very heat and drought resilient. In my gardens, I have noticed some reseeding out into the landscape. But I see that as an advantage – I get to share it with friends!

Purple Coneflower – Echinacea purpurea & cultivars

Most of the coneflowers you buy at the garden center are hybrids between E. purpurea and E. simulata (Glade Coneflower), though there are some of the other 5 species mixed in as well. But in my garden, I have the straight species of purple coneflower, as well as several cultivars. Purple coneflower is tough and heat loving, and blooms from June to August. Butterflies, bees, and other pollinators flock to purple coneflower in droves.

It grows 2 to 4 feet tall and 1 to 2 feet wide, though if you let is reseed out, the plants will grow together in large patches for greater effect. Purple coneflower is susceptible to Septoria Leaf Spot and Aster Yellows, though the former does not cause as much problems like it does on Rudbeckia. Also, several checkerspot butterflies feed on the foliage, and the wavy-lined emerald moth feeds on the flowers. The dried seedheads are eaten by finches in the late fall and winter.

Cultivars

• Sangrita Sombrero – has a nice habit and bright red flowers. All of the Sombrero Series are excellent plants. It grows 2 feet tall and wide.
• Pow Wow White – one of the best whites, it grows 2 feet tall by 16 inches wide.
• Fiery Meadow Mama – one of my favorite multi-colored coneflowers, it grows 2 feet tall and wide.
• Cheyenne Spirit – has multiple colors coming from a seed source, instead of hybridization and cuttings. It grows 2 feet tall and wide.
• Doublescoop Series – this series has double flowered cultivars, ranging in color. They grow 2 to 2.5 feet tall and 2 feet wide.

Hardy Hibiscus – Hibiscus hybrids & cultivars

What do you think of when I say hibiscus? The tropical looking flowers in Hawaii? Sometimes that is what I think of. But these hibiscus are hardy, at least, root hardy, in the Central Great Plains. Even though they are perennials, they still produce large and showy flowers in the heat of summer. And they barely come out of the ground until the soil temperature gets hot, nearly 70 degrees.

Hardy hibiscus comes in many sizes and colors, even multi-colored flowers. It only has one major issue – Japanese beetles. Otherwise, they are tough and great for a large area in the garden. Many grows 3 to 8 feet tall and wide. For maintenance, cut the flower stalks down in late fall.

Cultivars

• Cookies and Cream – has white flowers with dark purple leaves on plants that get 3 feet tall and 4 feet wide.
• Holy Grail – has red flowers and dark purple leaves. It grows 5 feet tall and wide.
• Lilac Crush – has dark green leaves with lilac colored flowers. It grows 4 to 5 feet tall and wide.

Sneezeweed – Helenium autumnale

Sneezeweed is a little known perennial for the garden. It is a great rain garden plant, as it can take it not only hot, but either wet or dry. The flowers are typically shades of orange or red, or a combination of the two. Plants grow 2 to 3 feet tall and wide and are great additions to the cottage garden, meadow garden, or butterfly garden.

Greyhead Coneflower – Ratibida pinnata

In my Sunny Cottage Garden, greyhead coneflower tops the height chart for heat loving perennials. It grows 4 to 6 feet tall and 2 to 3 feet wide. After forming a large clump of leaves, it sends up mighty yellow flowers, reminiscent of black-eyed Susans. The flowers blooms for weeks, from June to July, and are visited by a wide range of pollinators, but mainly bees.

One thing I recommend if you are planting this in the garden and not the meadow – deadhead as soon as possible, or you will receive hundred of new plants for free! Cut the old plants to the ground in late winter otherwise.

Purple Hummingbird Mint – Agastache foeniculum

Also known as blue giant hyssop, purple hummingbird mint is a great and prolific bloomer for the heat of summer. It grows 3 to 5 feet tall and 2 to 3 feet wide. In the summer, it blooms from June to September and is a great companion plant to false sunflower, purple coneflower, and daylilies. And the bees love it! Being a member of the mint family, hummingbird mint is deer and rabbit proof, and has no pest problems. Cut it back in later winter for cleanup.

Coreopsis ‘Zagreb’ – Coreopsis verticillata ‘Zagreb’

There are a lot of great coreopsis species and cultivars out there, but Zagreb is one of the best ones for the heat. It just does not stop blooming once it gets going! Zagreb blooms continuously from July to September, sometimes longer if it gets enough moisture. In the heat, it is hard to beat. It grows just 16 inches tall, but spreads slowly outward by rhizomes.

Zagreb may not be a pollinator magnet that some of the other heat loving perennials are, but it does attract flower flies and honeybees. Cut it to the ground in late fall or early spring for easy cleanup. It has not pest problems nor disease issues.

Cup Plant – Silphium perfoliatum

Last on my list is the cup plant, one of the taller heat loving perennials. Not only does this giant love the heat, but it can grow in wet or dry areas, making it another great rain garden plant. In my garden, it grows on the edge of the Meadow Garden, and also in the Monarch Waystation, two areas with different watering. Cup plant can be cut back in spring and early summer, to shorten the height of the plant without sacrificing flower production. It grows 4 to 8 feet tall and 3 to 5 feet wide. The bright yellow flowers are visited by bees and butterflies alike.

Conclusion

There are a lot of great heat loving perennials for the Central Great Plains. Planting just some of these perennials in your gardens will help ensure a great summer of flowering for you and the pollinators in your gardens. Try to put in as many as possible for maximum results.

Happy planting!