Bermuda grass (Cynodon dactylon) is a warm-season turfgrass valued for its dense, durable qualities in hot climates. The species is characterized by aggressive, lateral growth achieved through above-ground runners (stolons) and below-ground stems (rhizomes). Determining the height of Bermuda grass depends entirely on whether it is being actively managed as a lawn or allowed to grow freely. For manicured turf, the goal is to encourage horizontal spread rather than vertical growth.
Maximum Unmaintained Height
If Bermuda grass is left undisturbed, its vertical growth potential is substantial, reaching heights far beyond typical lawn standards. In ideal conditions with fertile soil and ample moisture, the grass can grow anywhere from 6 to 18 inches tall. Allowing the grass to reach this height is detrimental to its health as a turf. The lower portions of the grass blades become shaded, causing them to thin out and turn brown due to lack of light. Cutting the grass back drastically removes most of the green leaf tissue, resulting in a severe “scalping” effect that leaves behind only brown stubble.
Ideal Cutting Height for Turf
The ideal cutting height for Bermuda grass is significantly lower than for most other turf varieties, primarily because low cutting encourages dense, lateral growth. Recommended heights vary depending on the specific cultivar planted. Common Bermuda grass, which is generally less dense and has a coarser texture, performs best when maintained between 1 and 2 inches.
Hybrid and dwarf Bermuda varieties, such as Tifway or Tahoma 31, are designed to withstand much lower cutting heights and create a more manicured look. These varieties thrive when maintained in a range between 0.38 inches and 1.5 inches. Keeping the grass at the lower end of the recommended height range helps force the grass to spread horizontally, creating thick, mat-like turf that naturally resists weed encroachment.
Environmental Factors That Change Growth
The rate and height of Bermuda grass growth are highly responsive to environmental conditions, particularly nutrient and water availability. Nitrogen input is the most significant factor driving vertical growth; high levels of nitrogen fertilizer cause the grass to shoot up quickly. This rapid growth is often desirable during periods of repair or establishment but requires an increase in mowing frequency.
Water availability plays a substantial role in determining the growth rate. While Bermuda grass is known for its drought tolerance, a lack of adequate soil moisture will slow down its growth substantially. Conversely, ample irrigation combined with high temperatures accelerates the growth rate, demanding more frequent attention to maintain the target height.
Sunlight exposure alters the plant’s growth form. In areas with less than full sun, the grass will attempt to compensate for the lower light levels by elongating its leaves and internodes, resulting in a taller, thinner turf. In these partially shaded areas, the recommended mowing height should be raised slightly to maximize the remaining leaf surface area and reduce stress on the plant.
Mowing Frequency and Technique
Maintaining the correct height requires a focus on mowing frequency rather than simply adjusting the mower deck. The fundamental rule for healthy turf maintenance is the “one-third rule,” which dictates that no more than one-third of the grass blade’s total height should be removed in a single mowing session. For example, if a lawn is maintained at 1.5 inches, mowing must occur before the grass exceeds 2.25 inches.
During the peak growing season (late spring through late summer), this often necessitates mowing two or even three times per week to prevent excessive removal. Following this technique avoids stressing the plant and helps maintain the lower, green portion of the grass blade. Achieving the lowest recommended heights for hybrid varieties often requires the use of a specialized reel mower, which cuts the grass like scissors for a clean, precise finish.
Rotary mowers are suitable for maintaining common Bermuda grass varieties at heights of 1.5 inches or higher. Seasonal changes affect technique; many homeowners practice “scalping” in early spring by cutting the dormant grass down to a half-inch to remove dead material and promote uniform green-up. Conversely, raising the cutting height slightly in the late fall or during periods of extreme heat helps the grass withstand environmental stress.