So a client calls the studio in early June, and the first words she says, “Everything I planted last year is dead. What am I doing wrong?”
She’s not doing anything wrong necessarily. She is doing what any homeowner would do, picking plants that look incredible, digging a hole, putting them in the ground, watering them for a few weeks and hoping it works. The problem is never a lack of effort. The issue is that Charleston’s summer is absolutely brutal, and most landscape projects aren’t designed for it.
Here’s the short answer: you want to design a landscape for Charleston’s summer by beginning with the climate, not with the catalog in mind. You choose plants that evolved here. You build drainage into the plan before the first shovel even breaks ground. You meticulously consider shade, soil, and irrigation as a system, not just as afterthoughts. And you accept that a beautiful Lowcountry landscape is a different thing than a beautiful landscape anywhere else in the country.
The long answer is contained in this post.
What Charleston’s Summer Actually Does to a Landscape
Most people are aware that Charleston is hot. What is frequently underestimated is the combination of rainfall, heat and humidity and how that combination leads to a very specific set of problems.
According to data from The Citadel’s Near Center for Climate Studies, Charleston has recorded temperature highs of at least 90°F for 80 days or more in seven of the last fifteen years. That’s a lot of days of 90-degree weather. The 1991-2020 July high on average at Charleston Airport is 91.3°F. Furthermore, the heat index, which factors humidity into the equation, averages more than 34 hours above 105°F per summer. The state record heat index unofficially, was 124°F set here in Mount Pleasant in the Summer of 2011.
That’s not just a bad summer. That is undoubtedly a stress test.
And then there’s the rain to consider. Charleston gets roughly 51 inches of precipitation per year, much of it arrives in intense summer storms that can dump up to two inches per hour and then vanish as if it was never there. The ground, which is often heavy clay or compacted filler in newer developments, can not absorb it fast enough. This is the cause of the flooding. Then a week of no rain and scorching heat. Then flooding again, rinse and repeat (no pun intended).
This is what your landscape goes through just to survive. Not just survive, but thrive.
Why Most Landscapes Fail in the Lowcountry Summer
The failure pattern repeats over and over again and is always the same. A homeowner installs a beautiful mix of plants, most of them are perfectly fine in other climates, only to watch them struggle through July and August. Some may die from root rot after heavy rain and flooding. Still others bake in the afternoon sun on a west-facing slope with zero shade and zero mulch. A lucky few make it, but they are in rough shape by September.
The root (more puns!) cause is almost never the plants themselves. It is in the design decisions that came long before the plants: from the grading, to the soil prep, to the sun exposure analysis, and even the irrigation plan. All these factors matter, especially the absence of those things.
A landscape that performs well in Charleston begins with a site analysis, not a list of plants. That’s the core foundation of how we approach every project at REMARK Studio.
The First Thing to Get Right: Drainage
If there’s one thing that separates a landscape that lasts from one that does not in the Low country, it’s simply effective drainage. If you get it right then everything else gets easier. Get it wrong and no amount of high quality plants will save you or your landscaping project.
Charleston is at or near sea level. The soils in most neighborhoods, especially the newer developments, are heavily compacted and even filled with material that does not drain well. When a summer storm rolls however, that water will have nowhere to go fast enough, meaning it pools up and saturates the roots. It creates the kind of anaerobic soil conditions that will kill even highly drought-tolerant plants.
How to Read Your Yard’s Drainage Before You Plant Anything
Before you even put a single plant in the ground, you need to spend quality time in your yard after a heavy rain. Ask yourself, “Where is the water pooling at? Where does it move to? Does it drain quickly in certain spots?” These observations are more valuable than any soil test.
Here are a few things you can look for:
- Standing water that remains for upwards of 24 hours after the rain is indicative of a drainage problem, not just wet soil.
- Compacted areas where water inevitably beads up on the surface as opposed to soaking in need complete transformation or even structural drainage work.
- Low spots near the foundation of the house can be a serious concern and should be graded away from the structure prior to any planting.
If your site has significant drainage challenges, the solution is not to just pick highly wet-tolerant plants and hope it works out. The solution is to anticipate, and design for it in a proactive way. That could mean a rain garden, french drain, bioswale, or even a complete regrading of the site. At REMARK, drainage and stormwater management are a big part of every residential design we do, because in the Lowcountry it is a necessity. You can see the Remark approach to these challenges in our project portfolio.
Rain Gardens: The Smartest Thing You Can Do with a Low Spot
A rain garden is not a swamp. It is indeed a shallow, planted depression that is designed to not only collect, but also slowly absorb stormwater runoff. Done properly, it looks like a beautiful, natural bed for planting. Done extremely well, it solves drainage problems that have been plaguing a property for countless years and adds genuine visual interest to the landscape.
In addition to design, another key is in the plant selection. Rain garden plants need to be able to tolerate both temporary flooding and the dry conditions that follow between storms. Native plants are in most cases the right answer here. Purple Coneflower (Echinacea purpurea), listed on the City of Charleston’s pollinator plant guide as highly tolerant of drought, heat, humidity, and even poor soil, is a strong performer in this regard. So are native sedges, swamp sunflower (Helianthus angustifolius), and a multitude of various native grasses.
We have built rain gardens all across Charleston that have transformed from problem areas to focal points. The homeowners who were previously the most skeptical are now the easily most enthusiastic and for good reason. That’s what a good design sets out to accomplish.
Choosing Plants That Actually Belong Here
This is where most landscape decisions can often go wrong. This is not because people are careless, but because the plants available at most garden centers are selected specifically for broad appeal, not performance in Lowcountry. A plant that looks great in a garden in Virginia might not get the same result by August in Charleston.
Charleston sits in USDA Plant Hardiness Zone 9a, which means the average annual extreme temperature minimum sits between 20°F and 25°F. But the hardiness zone tells you only about cold tolerance and nothing else. This guide says nothing about heat, humidity, or the specific soil and drainage conditions of the Lowcountry. That’s where colloquial knowledge matters a great deal.
Native Plants: The Single Best Investment You Can Make
Native plants are the ones that evolved in their current location. They know the climate and they know the soils, the patterns of rainfall and the heat. Once this is established, they require dramatically less water and maintenance than is typical of non-native alternatives. Research from Rock Creek Landscapes shows that native plant gardens can require as much as 50 percent less water than non-native landscape designs. In a Charleston summer, that can mean a lot.
Here is a list of natives we look for most often in Lowcountry residential and commercial designs:
| Plant | Type | Key Strengths | Notes |
|---|---|---|---|
| Sweetgrass (Muhlenbergia filipes) | Ornamental Grass | Heat, drought, full sun | Pink plumes in fall; iconic Lowcountry plant |
| Wax Myrtle (Morella cerifera) | Shrub/Small Tree | Salt spray, heat, drought, sandy soil | Fast-growing privacy screen; birds love the berries |
| Purple Coneflower (Echinacea purpurea) | Perennial | Heat, humidity, drought, poor soil | Pollinators love it; long bloom season |
| Black-Eyed Susan (Rudbeckia hirta) | Perennial | Clay soils, heat, drought | Cheerful, tough, easy to establish |
| Dwarf Palmetto (Sabal minor) | Palm | Heat, humidity, shade tolerance | Native palm; extremely low maintenance |
| Carolina Jessamine (Gelsemium sempervirens) | Vine | Adaptable, fast coverage | SC state flower; can also be used as groundcover |
| Eastern Redbud (Cercis canadensis) | Small Tree | Understory, part shade | Appreciates afternoon shade in Lowcountry; stunning spring bloom |
| Rabbiteye Blueberry (Vaccinium virgatum) | Shrub | Hot, humid conditions | Native to SE; edible fruit; plant multiple varieties for cross-pollination |
Source: Brownswood Nursery, 15 Native Plants for Lowcountry Gardens
What to Avoid (and Why)
This is the part people don’t talk about enough. There are plants that look incredible in the spring and not so much in August. Then there are plants that do fine in the full sun of Charlotte but burn to a crisp in Charleston’s afternoon heat. Then there are plants that technically are rated for Zone 9 but they were never meant to handle the 79 percent average humidity that is common in August.
A few categories that you should approach with extreme caution:
Plants that need so-called “well-drained soil” but then get planted in Lowcountry clay without any changes being made. They will drown during a summer storm all to get baked in the heat once the rain subsides. The soil prep matters as much as if not more than the plant selection.
Tropical-looking plants that are in fact tropical look great in June. Unfortunately they’re often gone by October. If you are looking for the lush, tropical aesthetic, there is native and adaptive plants that can deliver this without the annual cost of replacement.
Non-native ornamental grasses that spread with a vicious intensity. Some of the most popular ornamental grasses sold in South Carolina are actually invasive to the Lowcountry ecosystem. Ask a knowledgeable person specifically about native alternatives prior to planting.
We cover this in more depth in our post on the biggest mistake people make with their Charleston landscape design.
Shade: The Most Underused Tool in a Hot Climate
Here’s something the majority of homeowners don’t consider until it’s far too late: shade is actually a design element, not just the byproduct of trees. During a Charleston summer, strategic placed shade can lower the surface temperature of a patio or planting bed by up to 45 degrees compared to a similarly sized unshaded surface. That’s the difference between a space you want to use and a space you would avoid.
Designing with Shade in Mind
The direction that your outdoor space faces matters a great deal. A patio that faces gets the full intensity of afternoon sun from about 2 PM through sunset, this is the hottest portion of the day. Without that shade, the space is completely unusable in both July and August. A few trees or a pergola with a climbing vine can transform it into something more suitable for people.
When we are conducting an analysis of a site, one of the first things we map out and plan is sun exposure throughout the day. Where is the morning sun located? Where does the afternoon sun hit the hardest? Where are all of the natural shade spots? That analysis ultimately drives the layout, the placement of plants, and the all hardscape decisions.
Here are some of the best shade tree examples for the Lowcountry:
- Live Oak (Quercus virginiana): The quintessential Charleston tree. Slow to establish but extraordinary once it matures. Evergreen, hurricane-resistant, and deeply beautiful.
- Bald Cypress (Taxodium distichum): Native, tolerates wet soils beautifully, and provides filtered shade. A great choice for low-lying areas.
- Southern Magnolia (Magnolia grandiflora): Dense shade, iconic bloom, and extremely tough once established.
- Eastern Redbud (Cercis canadensis): Smaller scale, perfect for courtyards and intimate spaces. Appreciates afternoon shade itself, which makes it a good understory option.
The key is all in the placement. A tree, when planted in the wrong spot, will create problems instead of solving them. Root systems, mature canopy spread, and proximity to structures all have to be considered in the plan. This is the exact kind of decision that benefits from working with and consulting a licensed landscape architect rather than taking guesses. Learn more about our approach to residential landscape architecture at REMARK.
Soil, Mulch, and the Things Happening Underground
Most of the action in a landscape happens unseen and underground. Roots, drainage, soil biology and moisture retention all go unseen. None of it is visible, and all of it is the determining factor in whether your plants thrive or perish.
What Charleston Soil Actually Looks Like
Lowcountry soils have a high degree of variability. In some areas, you have that typical sandy, fast-draining soil that can dry out quickly after the rain. In others, especially in those newer developments built almost exclusively on filled land, you will have compacted clay that retains water like a bathtub. In more historic neighborhoods, you might have a mixture of both, in addition to decades of organic matter and old filler material.
Before planting anything of any significance, it is worth understanding what you are working with. A basic soil test from Clemson University’s Home and Garden Information Center costs are negligible and tells you all about pH, nutrient levels, and organic matter content. That information changes what you plant and how you change the soil mix.
For clay-dominant soils, changing with adding compost and pine bark fines improves both drainage and structure. For sandier soils the organic matter helps retention of moisture long enough for roots to gain access to it between waterings
Why Mulch Is Not Optional in a Charleston Summer
Mulch is one of the most effective tools of a hot-climate landscape, and it’s criminally underused. Just a 2 to 3 inch layer of organic mulch accomplishes several things at the same time, it will insulate the soil against temperature extremes, retains the moisture so you have to water less, suppresses weeds that ultimately compete with your plants and slowly breaks down which will improve the soil structure over time.
According to the LSU AgCenter, mulch creates a protective barrier in between the soil and the external environment during hot climates, this keeps the soil meaningfully cooler than bare ground will. In July in Charleston, that makes a difference.
Pine straw is the most commonly used mulch in the Lowcountry because it works well. Hardwood mulch is another tenable option to choose from. What you want to avoid is piling mulch against the base of plants or tree trunks which leads to the common mistake called “volcano mulching.” This traps moisture against the bark and leads to rot and disease.
Irrigation: Watering Smarter, Not More
Watering a landscape in Charleston summer is not as simple as just turning on the sprinkler system. Too much water at the wrong time in the wrong place can cause as many problems as too little water. Root rot, fungal disease, and shallow root development are all consequences of irrigation that has been done incorrectly.
The Case for Drip Irrigation
Drip irrigation will deliver water directly to the root zone of the plants, slowly and efficiently. It does not wet the foliage, which can reduce the occurrence of fungal disease.. It doesn’t evaporate in the middle of the day the way overhead sprinklers often do. It also uses significantly less water overall.
For planting beds, especially the ones with native and/or adaptive plants, drip irrigation is oftentimes the right call. Overhead irrigation makes a great deal more sense for lawn areas, but even then, watering in the wee hours of the morning rather than the afternoon or evening reduces risk of disease and evaporation loss.
A well-designed and thought irrigation system also has multiple zones, so you’re not watering highly drought-tolerant natives on the same calendar as a newly installed lawn. Different plants have differing needs, and a good irrigation design accounts for that from start to finish.
How Long Does It Take for Native Plants to Establish?
This is a question we get non-stop, and the honest answer is this, one to two growing seasons. Native plants invest the first year or two in root development as opposed to above-ground growing. They may look like they’re doing nothing, they’re not in fact. They’re building the root system that is the foundation for surviving a Charleston summer without much help at all.
During the establishment period, consistent watering is incredibly important. After that, most Lowcountry natives need very little supplemental irrigation or outside help. That’s the payoff for being patient from beginning to end.
Putting It All Together: What a Heat-Resilient Lowcountry Landscape Actually Looks Like
A landscape designed for Charleston’s summer is never a compromise. It’s not a collection of tough, boring plants just simply arranged in a grid. Done well, it is one of the most beautiful things you can create in the entire region, because it works with the setting instead of fighting against it.
It has the shade where you need it, from the trees strategically positioned to block the afternoon sun. It has the drainage that moves water off the site efficiently and uses it where it can be helpful. It has native plants that look both intentional and refined, not wild and weedy, because the design is accomplishing the task of making them appear that way. It will have mulched beds that stay cool and moist even in the middle of August. It also has an irrigation system that supplements, not substitutes, for top tier plant selection and soil preparation.
That’s the difference between a landscape that just looks good in April and one that looks good all the time.
If you’re beginning a brand new project or even trying to figure out why your current landscape isn’t performing up to standard, the best first step is a conversation with an expert. We do a thorough site analysis to start off every project, and that analysis almost always reveals things that at first are not visible from the surface view. Reach out to the REMARK team and request more information here.
Frequently Asked Questions
What plants survive Charleston’s summer heat and humidity best?
The best performing plants in Charleston’s summer are the native and adaptive plants that have evolved in the climate that is all so typical of the Lowcountry. Sweetgrass, Wax Myrtle, Purple Coneflower, Black-Eyed Susan, Dwarf Palmetto, and Carolina Jessamine are all great choices for any project you have. These plants are highly heat and humidity tolerant once they have been established and in turn require significantly less water as well as maintenance than the typical non-native alternatives. See how we at Remark use these native plants in our residential landscape portfolio.
How do I fix drainage problems in my Charleston yard?
Start by observing where the water pools after a heavy rain and how long it sticks around for. If standing water stays in excess of 24 hours, you more than likely have a drainage issue that needs to be addressed structurally, not just with the selection of plants. Solutions range from regrading the site and installation of French drains to building a rain garden that can capture and slowly absorb the runoff. A licensed landscape architect can properly assess the site and recommend the correct approach. Contact REMARK Studio to discuss your unique drainage challenges.
What is the USDA hardiness zone for Charleston, SC?
Charleston, SC is in USDA Plant Hardiness Zone 9a, which is reflected in the average annual extreme minimum temperatures between 20°F and 25°F. However, the hardiness zone only addresses the cold tolerance. For Charleston’s summer performance, the more relevant factors are heat zone, humidity tolerance, and drainage requirements, this is someone with local plant knowledge matters just as much as zone ratings.
How much does landscape design cost in Charleston, SC?
Landscape design fees vary significantly based on the scope and complexity of the individual project being worked on. A simple residential design for a single outdoor space will typically start in the range of a few thousand dollars for design services alone, with construction costs varying widely based on the materials used, scale of project, and site conditions. At REMARK, we provide a transparent and clear scope and fee proposal after the initial discovery conversation, so there are no surprises. Request more information to get the conversation started.
How long does it take for a new landscape to look established in Charleston?
Most landscapes take around one to two full growing seasons to begin looking fully established. Native plants in particular have to invest heavily in root development throughout the first year, so above-ground growth may be minimal. By the second or third summer, a well-designed native landscape typically will look full, intentional, and require minimal intervention at most. Patience in the first year will pay off significantly in years two, three, and beyond.
Do I need a landscape architect or can I design my own yard?
For simple projects, a do it yourself approach can work. For anything involving significant drainage challenges, significant grading, Homeowners Association or ARB approvals, or even a substantial investment in hardscape and planting, working with an experienced, licensed landscape architect goes a long way in protecting that investment. A good design proactively catches problems before the building is underway and helps to coordinate all the systems (drainage, irrigation, planting, hardscape) as a whole. This ensures the final result performs up to par. Learn more about what REMARK Studio offers and how our refined process really works.
The Bottom Line
Charleston’s summer is not something you should or want to design around. It is something you design for. The homeowners who end up with landscapes they adore in September are the ones who started it all with the right questions. These are, “What does this site actually do with water? Where does the sun hit hardest? What plants belong here?” Those questions lead to better and more timely decisions, as well as better decisions that lead to landscapes that last a long time.
If you’ve been frustrated by plants that don’t survive in the past, spaces that are far too hot to use, or drainage that turns your yard into an ocean after every single storm, those aren’t happenstance. They are foundational design problems and these design problems have design solutions.
We’d love to help you find them all. Request more information here and let’s have a conversation about what your unique site needs.