Heat Tolerant Plants for the Sizzlin' Summer

As we brace for the heatwave that’s about to ring in the summer season and hope that it’s not a dark omen for weather to come, we wanted to take the lighter approach to embracing the oppressive warmth by celebrating some of our favorite heat tolerant selections available here at the nursery.

You know a plant can take some heat when it has a native range spanning throughout Texas and Louisiana, especially when its species name proves itself to be as southern as its discoverer, the Texan father of botany, Ferdinand Jacob Lindheimer. Gaura lindheimeri ‘Siskiyou Pink’, is as much of a delight in the south as it is in cooler, northern climates, with its delicate, fairy-like sprays of true pink flowers that distinguish it from its common white-flowering brethren.

‘Siskiyou Pink’ gaura is no stranger to some brutal late afternoon sun and suffocating levels of humidity in its native region, although its fluttering, airy blooms evoke breezy imagery and a mesmerizing display of carefreeness that’s sure to take anyone’s mind right away from the scorching heat. Gaura lindheimeri ‘Siskiyou Pink’ is tolerant of a variety of soils, resistant to pesky deer, and boasts a surprisingly long bloom time - perfect for livening up the landscape right through the heart of the summer.  While ‘Siskiyou Pink’ gaura may belong to a much further southern part of North America than the tri-state area, Mid-Atlantic summer staple Coreopsis verticillata is a heat tolerant requirement for native pollinator gardens that are designed to attract and sustain local wildlife.  

An explosion of yellow blooms erupts over thin, threadlike foliage that gives this species its common name, seemingly hypnotizing honeybees, hoverflies, and sweat bees alike.  ‘Moonbeam’ threadleaf tickseed, with its pale lemon flowers that appear almost as though struck by rays of moonlight, and low-growing, compact Coreopsis verticillata ‘Zagreb’, which features warm, golden blooms, both provide a gently mixed palette of yellows to the sunny rock garden bed, perennial border, or container arrangement.

If a heat-tolerant centerpiece is what you’re looking for to flesh out your Coreopsis verticillata mixed container, Yucca filamentosa ‘Silver Anniversary’ has the pizzazz, punctuality, and perseverance necessary to make the perfect, durable, long-lasting container combination. Compact, blue-green rosettes of sharply textural, succulent foliage offer a lovely juxtaposition to the lush greens and purples of midsummer, with its desert-like appearance giving exotic allure even when the tall, human-sized bloom spikes with their creamy bell-shaped flowers aren’t on display.

Or perhaps you’re looking to create a cool, shady hangout right in the heart of a heat-prone landscape. Catalpa speciosa, our native Northern catalpa, is a large deciduous species with dinner-plate sized foliage and seedpods of equal enormity in fall that emerge from a previous late spring bloom of large, white, orchid-shaped flowers with purple to maroon and orange speckles.  

I’m fortunate enough to have a pair of young catalpa trees growing in my swampy backyard, in a low-lying former creek bed that catches runoff from the Delaware Canal. In fact, my stretch of the towpath in lower Bucks County features quite an established few clusters of Northern catalpa trees that grace pedestrians and cyclists with their fragrant blooms in late spring, followed by their interesting and persistent seed pods that cling to the branches deep into winter.

Interestingly, their location so close to the canal and the Delaware River seems not to be coincidental - although once widely regarded as ornamental street and landscape trees, Northern catalpa trees may have once been utilized for another purpose.  Catalpa speciosa is the host plant for perhaps one of the best fishing bait insects in North America: the Catalpa sphinx moth, Ceratomia catalpae. In fact, Northern catalpa trees and their sphinx moths are occasionally raised solely for the purpose of having access to some of the best fishin’ bait this side of the Rockies, and even the North Carolina Cooperative Extension reports most of their catalpa sphinx inquiries are mostly about how to prevent predators from stealing all the grub for themselves.