Lemongrass is not drought tolerant. In fact, compared to other ornamental grasses, it ranks among the most susceptible to drought stress. Native to the tropical climates of India and Sri Lanka, lemongrass thrives with 2,500 to 3,000 millimeters of annual rainfall, which is roughly 100 to 120 inches per year. That’s more rain than most of the U.S. receives, even in wetter regions like the Pacific Northwest or the Gulf Coast.
Why Lemongrass Struggles Without Water
Lemongrass (Cymbopogon citratus) evolved in tropical and subtropical environments where moisture is abundant and consistent. A 2023 study published in Plants tested four ornamental grass species under water deficit conditions and found that lemongrass was the most susceptible to drought of all four. Its seed germination, vegetative growth, and overall survival dropped sharply when water was restricted. The researchers noted that lemongrass is so poorly adapted to dry conditions that it has almost no chance of becoming invasive in arid or semi-arid climates.
This makes sense when you consider how the plant is built. Lemongrass has long, thin leaves with a large surface area relative to its root mass. That design works well in the tropics, where the plant can afford to lose moisture through its leaves because rain replaces it constantly. In drier conditions, the same leaf structure becomes a liability, pulling water out of the plant faster than the roots can replace it.
Signs Your Lemongrass Needs Water
Drought stress in grasses follows a predictable pattern. The earliest sign is a grayish or bluish cast to the leaves, which looks subtly different from the plant’s normal bright green. If dryness continues, the leaves will begin curling or rolling inward, particularly during the hottest part of the day when the air is driest. This curling is the plant’s attempt to reduce the surface area exposed to sun and wind, slowing water loss.
If you notice curling only around midday and the leaves flatten out by evening, the plant is mildly stressed but recovering overnight. If the curling persists into the cooler hours, or if leaves start dropping or turning brown at the tips, the stress is more serious and the plant needs water immediately. Prolonged drought can kill lemongrass outright, unlike tougher ornamental grasses that simply go dormant and bounce back when rain returns.
How Much Water Lemongrass Actually Needs
To keep lemongrass healthy, aim for consistently moist (not waterlogged) soil. In most temperate climates, that means watering deeply at least two to three times per week during summer, more often in containers or sandy soil that drains fast. Lemongrass grown in pots dries out especially quickly because the root zone is limited and exposed to heat on all sides.
A good rule of thumb: if the top inch of soil feels dry, water thoroughly until it drains from the bottom of the pot or saturates the root zone in the ground. Mulching around the base of the plant with two to three inches of organic material helps retain soil moisture and keeps roots cooler, which reduces the plant’s overall water demand.
Growing Lemongrass in Dry Climates
If you live somewhere with hot, dry summers, you can still grow lemongrass, but it will need consistent irrigation. A few strategies help:
- Afternoon shade. Planting where the grass gets morning sun but protection from the harshest afternoon heat reduces water loss significantly.
- Drip irrigation. A drip line or soaker hose on a timer delivers water directly to the root zone without waste from evaporation or runoff.
- Container growing. In very dry regions, growing lemongrass in a large pot gives you more control over moisture levels. You can also move the pot to shadier spots during heat waves.
- Heavy mulching. A thick layer of straw, wood chips, or compost around the base conserves moisture and moderates soil temperature swings.
Even with these measures, lemongrass in arid or semi-arid climates will never be a low-maintenance plant. If you’re looking for a similar ornamental grass that can handle drought, fountain grass and other species adapted to drier environments are better choices. Lemongrass rewards you with its citrus fragrance and culinary versatility, but it asks for regular water in return.