Perennials That Don't Seem to Notice a Heatwave – These 7 Plants Are Unfazed by Temperature Spikes
When the going gets tough, these plants keep going
There are a unique category of plants who don’t blink an eye at high temperatures, they barely notice and carry on regardless. These plants deserve a bit of love, so let’s shine a spotlight on some tough perennials that don’t seem to notice a heatwave.
A heatwave takes a heavy toll on gardeners and their plants, but not these seven. These perennial plants like sun and don’t need lots of extra watering when the temperature rise. Whether because of their deep roots, native climate, or unique characteristics, it makes them drought-tolerant and able to thrive even during a heatwave.
I spoke to garden designers and plant experts to get their picks of perennials that don’t seem to notice a heatwave. This list proves you can fill a garden with drought tolerant plants without sacrificing beauty, whether it is glorious blooms or textural foliage, or wildlife, as these perennial plants are beacons for pollinators.
Russian Sage
This robust, drought-tolerant perennial will stand tall throughout the hottest summers. It is tough yet elegant, bringing an airy feel to a space with its aromatic silvery stems and panicles of lavender-blue flowers.
Laura Janney of The Inspired Garden is a huge fan, and claims, ‘There is nothing like the look and smell of Russian sage.’
‘The soft, delicate blooms create a beautiful background and lovely contrast with bolder flowers in the garden,’ she adds. ‘Its deep roots help pull up moisture so not much watering is needed.’
Russian sage thrives in the sun and won’t be daunted by a heatwave. It is ideal for those sunny, drier spots in which many other perennials struggle. It is a perfect plant for a dry garden, rock garden, or xeriscaping, while also looking at home in cottage garden borders.
It needs well-draining soil and dislikes wet feet, so avoid overwatering. The soil needs to dry out between waterings, and the plant will sulk if it continuously gets overwatered.
You can get a live Russian sage plant at Nature Hills that will grow 3-5 feet tall and attract pollinators.
Laura Janney is a renowned landscape architect and designer, and CEO of The Inspired Garden Masterclass. She won the Houzz Best in Design award in 2023 for her work in the New York area. Driven by the belief that flowers feed the soul, Laura sees gardens as more than simply outdoor spaces – they are living, breathing sanctuaries that awaken the senses.
Yarrow
Yarrow (Achillea millefolium) is a native North American plant and a great addition to challenging hot and dry spots in the garden. It is a resilient, drought-tolerant perennial plant that continues to put on a show through dry conditions.
Its flat-topped clusters of flowers come in a variety of colors, and the ferny green foliage adds texture to flower beds. And it is not only gardeners who adore yarrow, as pollinators also love it.
Laura Janney hails this long-flowering perennial as being ‘extremely low maintenance’ once established in the garden. ‘It doesn’t need much water as it has deep roots to pull moisture from and its small feathery leaves allow it to hold on to water more easily,’ she explains.
Yarrow won’t blink in the eye of a heatwave. This tough perennial thrives in challenging conditions. Indeed, it prefers lean soils and dry conditions, as too much water or fertilizer often causes the plants to flop. It ranks among one of the best plants for poor soil.
One word of caution. Yarrow is notorious as a self-seeding plant. You can deadhead yarrow to prevent it spreading if you don’t want them popping up around the garden. It is advisable to avoid planting yarrow near natural areas, unless you are prepared to manage the potential spread.
You can get a pack of Colorado Blend yarrow seeds at Botanical Interests that will grow into plants topped with red, pink, yellow, and white blooms.
Wild Bergamot
Wild bergamot (Monarda fistulosa) is a perennial plant in the mint family that commonly grows in drier soils across North America.
This monarda variety is native to most of North America. Its heritage makes it a low-maintenance, drought-tolerant plant for meadows, herb gardens, or pollinator gardens.
Kathy Thornton, Natural Lands Project Field Technician at Washington College, explains: ‘Native perennial plants are acclimated to the region and tend to require less maintenance, less water, and less fertilizer.’
‘Wild bergamot stands tall with soft lilac-colored blooms that offer nectar for butterflies and hummingbirds,’ continues Kathy. ‘The blooms dance in the summer breeze and, when planted en masse, can create a stunning meadow or cottage garden vibe.’
The flowers and leaves of wild bergamot are edible and have a range of uses. For example, the leaves can be used to make tea.
If you are looking for a pollinator plant that won’t be fazed by a heatwave, try growing bee balm (bee balm is another name for monarda). You can get a pack of heirloom wild bergamot seeds at Amazon to grow the plants at home.
Kathy Thornton is the Natural Lands Project Field Technician, which is part of the Center for Environment and Society at Washington College. The Natural Lands Project works with private and public landowners across Maryland’s Eastern Shore to convert marginal cropland into diverse native meadows, wetlands, and forests.
Lamb’s Ear
Lamb’s ear (Stachys byzantina) is an excellent drought-resistant ground cover plant that can often be overlooked. This perennial plant won’t be fussed by a heatwave, though, thanks to its unique foliage.
‘Any perennial with fuzzy leaves like lamb's ear is very heat-tolerant,’ says Lorraine Ballato, a hugely experienced gardener and author. ‘Those fuzzy leaves protect the foliage from scorching sun and heat while adding a nice silver-like contrast to the garden.’
As Lorraine mentioned, a key to the beauty of lamb’s ears is its silver-grey foliage, which forms a low, textured mat. These leaves are very velvety, and gardeners cannot resist the urge to touch them. A textural carpet of Lamb’s ear makes great edging along borders or garden paths.
The ground cover plant only reaches 6-8 inches tall and produces pink-purple flower spikes from late spring to early summer. The plant needs watering to establish, but afterwards can survive extended periods of drought.
When you water the plants, avoid overhead watering. The fuzzy leaves trap moisture, which leads to powdery mildew and other fungal diseases.
Get a packet of Lamb’s ear seeds at Amazon to sow indoors or outdoors in spring.
Lorraine Ballato is a gardening and hydrangea expert and the the author of the international best selling book 'Success with Hydrangeas', available at Amazon. She is also an in-demand speaker throughout the US and the resident hydrangea expert at the New York Botanical Garden.
Desert Marigold
If any perennials don't seem to notice a heatwave, it will be those that are naturally acclimatized to tough, dry, hot landscapes.
Desert marigold (Baileya multiradiata) is a very resilient plant that thrives in challenging conditions found naturally across the southwestern United States and northern Mexico.
Michele Chambliss, a garden designer from Perennial Garden Consultants in Las Vegas, is used to picking plants that can cope with tough conditions, where temperatures can top 100 degrees, and she highlights desert marigold as one of her most resilient perennials.
‘It's the tiny hairs on the leaves and stems which give this desert native perennial a silvery cast and help it to survive extreme heat and drought,’ she says. ‘Sunny yellow flowers blooming nearly year-round bring cheer to any hot, well-draining garden.’
Desert marigold is a good plant for sandy soil and grows in mounds a few feet tall and wide. The long-lasting, yellow, daisy-like flowers are papery in texture, and stand out against the gray foliage.
You can get a pack of desert marigold seeds at Walmart
Specializing in designing with native plants, desert cottage garden style, container design, and edibles, Michele Chambliss is a 'plant-driven' garden designer based in Las Vegas, NV. An American Society for Horticultural Science Certified Horticulturist, she has worked in many facets of horticulture for 25 years, from maintenance to design.
Desert Globemallow
Michele Chambliss also recommends the Desert globemallow (Sphaeralcea ambigua) as another heat-loving, drought-resistant native perennial. It is in the mallow family and offers fuzzy grey-green leaves and colorful bowl-shaped blooms.
‘I love the luscious orange flowers that cover the plant in spring, but they sometimes can be pink, lilac, or white,’ adds Michele. ‘It is another desert perennial. This one grows with a shrubby habit to about 3 feet x 3 feet, so it needs a bit more room than the desert marigold.’
Desert globemallow, also known as the desert mallow or desert hollyhock, is versatile. It can work equally well in a mixed flower border or a gravel garden. It can tolerate even poor soil types, but must drain well. The plant won’t be happy in wet soils.
There is a sensibility to taking notes from desert landscaping ideas when thinking of perennials that will continue to thrive in a heatwave. Desert mallow ticks all the right boxes; it is tough, wants lots of sun, but doesn’t need a large amount of water.
You can get a pack of desert globemallow seeds at Amazon
Little Bluestem
Little bluestem (Schizachyrium scoparium) is a perennial native grass that thoroughly enjoys warm temperatures and dry conditions. This warm-season ornamental grass reaches 2-4 feet in height and offers interest throughout the seasons.
‘Little bluestem is a beautiful bunch grass with bluish-green foliage that serves as a host plant for a variety of skipper butterflies,’ says Kathy Thornton from Washington College. ‘In fall, the blue and green leaves fade to orange and purple.’
‘With deep taproots, this grass can tolerate the summer heat and drought,’ she adds.
Gardeners can plant little bluestem in mixed borders, wildflower meadows, cottage garden beds, rock gardens, or dry gardens. Its smallish size makes it suitable for gardens of all sizes where heat and humidity are common.
This ‘Standing Ovation’ little bluestem plant from Nature Hills turns burgundy-red in the fall.
What to Shop
A pair of comfortable and durable gloves made from soft full-grain cowhide leather on the palm and spandex on the back. They will protect your hands from cuts or abrasions during any gardening tasks.
A shade cloth can protect plants from the sun in a heatwave. This shade cloth offers a 50% shade rate, measures 10 x 20 feet, and can be installed over plants before rising temperatures.
This blue oval watering can is strong and made from galvanized steel. It can hold 2.5 gallons of water and comes with a removable rosette for watering more delicate plants.
In reality, any plant will be happier when watered during a heatwave. Even drought-tolerant plants will need watering. And when you do water, you want the most water possible to hydrate your plants, rather than be lost to evaporation.
This is why it is crucial to water plants in hot weather deeply and in the morning. Doing so ensures the water soaks down to the roots and the plants have time to absorb it before the temperatures rise.
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