From Dry Spells to Downpours
It hasn't rained in three weeks… until it rains three inches in an afternoon. If that sounds familiar, this is for you! We're talking drought, downpours, runoff, root systems, and how to choose plants for landscapes that can't seem to make up their minds.
Drought One Week, Flooding the Next
The soil is cracking, plants are thirsty, and everyone is watching the forecast. Then, seemingly overnight, a thunderstorm rolls through and drops enough rain to turn a parking lot into a small lake. Welcome to landscaping in the Mid-Atlantic.
Pennsylvania summers have long brought a mix of heat, humidity, thunderstorms, and occasional dry spells, but landscapes are increasingly being asked to handle rapidly changing conditions. The challenge isn't simply finding plants that can survive drought or tolerate wet soil. It's understanding the site and choosing plants that can perform when conditions don't stay neatly inside one box.
Start with the Site
It can be tempting to search for a magical plant that tolerates drought, flooding, clay, shade, deer, salt, poor soil, and maybe also does your taxes. Unfortunately, even the toughest plants have preferences. The first step is understanding how water moves through a site. Where does it collect? Where does it run off? Which areas dry out first? Is the soil compacted? Is runoff coming from a roof, parking lot, or other impervious surface?
These questions matter because even a relatively small landscape can contain several different moisture zones. Rain gardens, for example, are intentionally designed around changing moisture conditions, with wetter areas receiving different plants than the edges and upper portions of the site. The goal isn't to find one plant that does everything. It's to put the right plants in the right places and let the landscape work a little harder for itself.
Look Below the Surface
When we talk about resilient plants, the conversation often focuses on what we can see above ground: foliage, flowers, and whether the plant still looks presentable after a heat wave. But resilience starts underground.
Deep or extensive root systems can help plants access moisture during dry periods while also stabilizing soil and improving infiltration. Native plants are often valuable in these situations because many have evolved with regional soils and weather patterns and can develop root systems that help slow runoff and reduce erosion.
This doesn't mean every native plant belongs in every wet spot or that every drought tolerant plant can handle standing water. Site conditions still matter. A plant adapted to dry, well-drained soil isn't suddenly going to enjoy sitting in water just because someone labeled it “tough.” Even plants have boundaries!
Moisture Zones
Look at how moisture behaves across the landscape:
Areas that dry quickly: Sunny slopes, sandy soils, exposed sites, and areas with fast drainage may benefit from plants adapted to heat and lower moisture.
Average or adaptable areas: These are often the powerhouses of the landscape! Plants that can handle normal garden conditions while tolerating occasional dry spells or periods of extra moisture.
Areas that collect or receive runoff: Swales, rain gardens, and locations near downspouts may experience periodic inundation followed by much drier conditions. Plants here need to tolerate fluctuation, not necessarily live in standing water permanently.
Establishment Still Matters
Drought tolerant does not mean “plant it and forget it.”
A plant can have excellent drought tolerance once established and still need consistent watering while its root system develops. Newly installed rain garden plants may also require supplemental watering during dry periods, even though they are literally planted in a garden designed to capture rainwater. The irony is not lost on us.
Proper establishment gives plants the opportunity to develop the root systems that make them more resilient later. Deep, less frequent watering during dry periods can encourage stronger root growth, while shallow, frequent watering may result in weaker root systems.
In other words, resilience isn't always instant. Sometimes it takes a season, or two, to get there!
Resilient Plant Palette
As weather patterns continue to challenge landscapes, the conversation around plant selection is becoming less about finding the single “perfect” plant and more about creating resilient plant communities.
That means considering:
- A diversity of species rather than relying on a monoculture
- Plants with different root structures and growth habits
- Species suited to the site's natural moisture patterns
- Plants that can tolerate occasional stress without requiring constant intervention
- The establishment period, not just mature plant performance
Diverse plantings can also provide a little insurance. If one species struggles during an unusually dry or wet season, the entire planting doesn't necessarily fail along with it.
By understanding how water moves through a site, paying attention to soil and drainage, and selecting plants for specific moisture conditions, not just broad labels, we can build landscapes better prepared for whatever the forecast decides to do next. Because if there's one thing we can count on, it's that the weather will keep us humble!
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