Guide to Heat-Tolerant Plants and Watering During the Summer
South Carolina summers are hot and humid, which can make summer watering and gardening difficult. But fear not, for we can guide you on the best heat-tolerant plants for upstate South Carolina gardens and on how to water your lawn and outdoor plants during the summer (and, yes, there are wrong ways to water!).
How Hot and Humid is South Carolina During the Summer?
Temperatures can range from 83℉ and 90℉ from June to August in upstate South Carolina. We can have up to 89% humidity during the summer in Seneca, South Carolina, which is often described as “muggy” or “oppressively humid.”
High temperatures and high humidity can cause plants to mildew, get fungal disease, and acquire blight. Slugs and snails can also become rampant with the mixture of high temperatures and high humidity.
So, what should you do? How do you save your garden from hot temperatures and high humidity? There are two key factors you have to address to save your plants this summer: heat–tolerant plants and summer watering best practices. Let’s start with the best heat-tolerant plants for upstate South Carolina homes.
Top 7 Plants for South Carolina Summers
Some plants are naturally heat-tolerant, meaning they stay healthy and colorful during the heat. So, the plants will be fine and won’t dramatically droop when the temperature rises. This means that when you plant heat-tolerant annuals, perennials, and shrubs, you’ll have less work to do during the summer. Here are some of our favorite heat-tolerant plants that consistently perform well:
Lantana
Lantanas are vibrant, colorful flowers that grow in small clusters. They come in white, purple, pink, yellow, orange, and red. Many lantana varieties even have bi-color varieties, which are perfect if you want a sea of color in your garden.
They are long-blooming flowers that help support South Carolina’s pollinators. Hummingbirds are especially attracted to lantana flowers’ tubular shapes. So, if you want hummingbirds in your yard, plant lantana.
Although most lantana are considered annual plants in our area, some varieties may overwinter if planted in the spring in ideal conditions. Give lantanas well-draining soil, full sun, and yearly fertilization with a balanced fertilizer.
Coneflower (echinacea)
Coneflower is one of our favorite flowers because it supports local pollinators. These perennial flowers attract birds to gardens and they come in a variety of colors, coneflowers come white, pale purple, bright purple, pink, green, yellow, orange, and red. Some coneflowers even have multicolored blooms, although those tend to be hybrids rather than natural varieties.
Coneflower can be drought-tolerant (very useful for hot summers!) and love full sun. Give them a little compost at the start of the growing season, and then enjoy their blooms.
Sedum
We love sedums! In fact, we love them so much that they made it onto our list for “Low-Maintenance Plants for Your South Carolina Garden.” We have to put them here too because they are the perfect flowers for hot summers and they are drought-tolerant. Plus, they are great flowers for pollinators, especially butterflies, and who doesn’t love their adorable star-shaped flowers?
Water sedum when you’re first establishing it, and then leave the plant alone. Sedum will thrive in upstate South Carolina’s humidity and heat without much attention from you (other than to admire its beauty, of course!).
Knock Out Roses
We have extensive rose expertise at Head-Lee Nursery (seriously, check out our rose guide for the best roses you’ve ever seen), and we love Knock Out Roses for the summer’s heat and humidity.
Knock Out Roses need full sun and well-draining soil. They do well as in-ground flowers. They have a reputation for being easy-to-care-for and they are more resistant to rose diseases, such as black spot fungus, compared to other rose varieties. For more guidance on how to care for roses, check out our post on “How to Grow Roses in South Carolina.”
Black-eyed Susan
Black-eyed Susans (also known as rudbeckias) are heat-tolerant perennials that bloom from June to August. You can extend the flowers’ blooming time by continually deadheading, which means cutting off any spent blooms. This signals to the plant that its job of producing seeds and reproducing is not done yet, so it better get back to making more flowers bloom.
Most black-eyed Susans have daisy-esque petals that are yellow, gold, bronze, orange, red, or mahogany. Some petals are even bicolored. The flowers’ centers are often green, dark brown, or black.
You’ll love these easy-to-grow and low-maintenance flowers for your South Carolina garden. Plus, black-eyed Susans are drought-resistant, don’t have many pests, are deer-resistant plants, and give pollinators much-needed food as they head into the fall and winter.
Give black-eyed Susans full sun and well-draining soil (although they’ll thrive in just about any kind of soil).
Crape Myrtle
Crape myrtle are trees and large shrubs with showy, crinkled flowers that bloom from summer into early fall. This heat-tolerant plant is easy-to-grow and produces stunning flowers for any South Carolina garden. Truly, you’ll be the envy of all the neighborhood if you have a crape myrtle in your yard.
Crape myrtle flowers can be white, pink, lavender, purple, or red. Then, the foliage turns vibrant yellows, oranges, and reds in the fall.
Crape myrtles grow well in full sun. While they can grow in partial shade, oftentimes you won’t get as many blooms or as healthy of blooms compared to if the plant was in the sun. Luckily, though, crape myrtle does well in almost any soil type as long as it has good drainage.
Portulaca
Portulaca (also known as a moss rose) is typically an annual flower grown low to the ground. The plant’s leaves are spiky and succulent-like, which allows portulaca to be drought-tolerant and heat-tolerant. Its flowers come in white, yellow, orange, red, and several shades of pastels. They are some of the cutest and most colorful flowers you can have in your South Carolina garden. Also, portulaca flowers only open on sunny days from sunrise to sunset. How neat is that?
Give portulacas full sun, well-draining soil, and only water them if you’re having a spell of hot weather with little or no rain.
How to Water During the Summer
Choosing the right plants is only half the battle. Proper watering techniques ensure your garden not only survives but thrives through the South Carolina summer. Remember, it's not just about how much you water, but how and when you water. So, here are the best practices for watering in-ground plants, lawns, and potted plants during the summer.
Watering In-Ground Plants
In-ground plants get the benefit of rainwater, but they still may need some extra watering and care to stay healthy and vibrant. Follow these watering steps to keep your in-ground plants in tip-top shape during the summer:
Water deeply and routinely: Water deeply two to three times a week rather than light, daily sprinkles to encourage deep root growth. Deep watering causes to develop a deep root system by forcing plant roots to reach down into the soil where it's cooler and where the soil retains the most moisture. Please remember that new plants usually need daily water when they are first planted, especially if planted during the late spring or summer.
Water in the Early Morning: Water in the early morning before the sun gets too intense. This allows the water to soak into the soil before it evaporates. Morning watering also allows leaves time to dry before the night, which reduces the risk of fungal diseases and prevents other diseases.
Watch for Wilting Leaves: Wilting leaves during the hottest part of the day can be a temporary sign of stress. But, if they don't perk up by evening, then the plant probably needs water.
Add Mulch: Place a 2-4 inch layer of organic mulch around your plants to insulate the soil, retain moisture, suppress weeds, and keep roots cool.
Watering Lawns
Lawns have their own watering challenges, but there are some crossover best practices between watering lawns and watering in-ground plants. For healthy lawns, follow these watering guidelines:
Water deeply: Just like with your in-ground plants, deep and infrequent watering is key for lawns. Give your lawn about one inch of water each week over the course of one or two watering sessions. You can use a rain gauge to measure the amount.
Avoid Daily Sprinkles: Light, daily watering encourages shallow root systems. Shallow roots make your lawn more susceptible to drought stress.
Water in the early morning: Water your lawn in the early morning to minimize evaporation and allow grass blades to dry before nightfall, which helps prevent fungal growth.
Adjust for rainfall: Keep an eye on the forecast! If South Carolina delivers a good summer downpour, you can adjust your watering schedule accordingly.
Watering Plants in Pots
Container plants need their own special watering practices. For potted plants, follow these watering instructions during the summer:
Water daily (or even twice a day!): Container plants are vulnerable to drying out in the heat because of increased air circulation around the pot and smaller soil volume compared to plants in the ground. So, the amount of water needed for potted plants is more than for in-ground plants. Potted plants will likely need daily watering, sometimes twice a day during peak heat in South Carolina.
Check soil moisture: Before watering, stick your finger about an inch or two into the soil. If it feels dry, it's time to water. If not, then leave the potted plant alone.
Water until it drains from the pot: Water slowly until you see water draining from the bottom of the pot. This ensures that the entire root ball is saturated.
Check for excessively dry soil: Soil that has lost all of its moisture will contract and become hydrophobic. This means all of your water rolls off of your soil rather than soaking in. Repeated soaking or allowing the pot to stand in water for a short period could correct this issue.
Use the right pot: What pot you use largely depends on the plant itself. However, know that terracotta pots are porous, which leads to faster evaporation. Plastic or glazed pots retain moisture well.
Group pots together: Create a microclimate that reduces evaporation by grouping pots together. The pots that stick together retain moisture together!
Use larger pots: Larger pots hold more soil and therefore more moisture than small pots. So, large pots won’t dry out as quickly as small containers.
Reach Out to Head-Lee for Heat-Tolerant Plants and Gardening Supplies
By combining the resilience of heat-tolerant plants with smart, targeted watering techniques, you can enjoy a vibrant and healthy outdoor space throughout the South Carolina summer. You can also check out our watering guide for more information.
If you have any questions or need further guidance, don't hesitate to visit us at Head-Lee Nursery. We have over 40 years of experience, and we’re deeply rooted in the Seneca gardening community. Whether you’re a gardening expert or a gardening beginner, we have something for everyone and we’d love to help make your gardening ideas bloom.
