St. Augustinegrass lawn management

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St. Augustinegrass is a coarse-textured, stoloniferous grass widely grown in the state of Texas and throughout the southern United States. In general, St. Augustinegrass is considered to be the most shade tolerant warm-season grass. It typically grows best in warm temperatures ranging from 80 to 95 degrees and will become brown or off-colored during winter dormancy. St. Augustinegrass is established vegetatively using sod, sprigs and plugs. 

Currently, seed is not available. Strengths: Shade tolerance, moderate drought tolerance, deep rooting potential and rapid establishment rate. Weaknesses: Many cultivars do not tolerate colder weather and traffic as well as some other warm-season turfgrasses. 

St. Augustinegrass is susceptible to diseases such as large patch, gray leaf spot, and take-all root rot. 

Susceptibility can be significantly influenced by management practices, such as irrigation and fertilization. It is also susceptible to chinch bugs.

St. Augustinegrass 

Shade Tolerance 

Warm-season turfgrasses offer fewer shade-tolerant options compared with their cool-season counterparts. St. Augustinegrass thrives in full sun, but some species and cultivars can survive in partial to moderate shade. 

St. Augustinegrass is generally considered the most shade-tolerant warm-season turfgrass but will still require a daily minimum of 4 to 6 hours of light to survive. Shade tolerance will vary across St. Augustinegrass cultivars and will be further influenced by the nature of shade, such as filtered light versus structural shade from buildings and other environmental conditions. In general, warm-season turfgrasses respond favorably to afternoon light compared to morning light. 

Warm-season turfgrass may not be able to survive in heavily shaded areas, particularly under growing trees with increasingly dense canopies. 

Under these circumstances, you may want to consider alternatives, including mulch or shade-tolerant perennial plantings. 

For more information on alternative planting options for shade, please see Shade Gardening for North Texas.  

Establishment 

Best establishment guidelines are that warm-season turfgrasses be planted during warmer months when they are actively growing to promote quick and successful establishment. 

Ideally, St. Augustinegrass should be planted in the late spring and early summer to avoid temperature extremes. 

This time of year will also often offer greater natural precipitation to aid in establishment compared with drier months in the late summer. While St. Augustinegrass sod can be planted year-round in many parts of Texas, it is important to be mindful of how environmental conditions during other parts of the year may influence the success of establishment. 

Allow as much time as possible for turfgrass roots to develop prior to fall and winter frosts. 

St. Augustine is susceptible to winter-kill in some parts of Texas, and successful establishment is vital for winter survival. St. Augustinegrass has a stoloniferous (above-ground stems) growth habit, which means it has the capability to spread laterally to create new root and shoot growth. It is important to note that St. Augustinegrass does not produce rhizomes (belowground stems) like bermudagrass or zoysiagrass. 

This can be important to consider when determining appropriate cultivation practices, as significant above-ground injury can have greater consequences to overall plant health.

Mowing

Proper mowing is vital to the prolonged health of your turfgrass lawn. The objective when mowing turfgrass is to encourage dense lateral growth without removing excess above-ground vegetation. 

This is achieved by mowing at the appropriate height and frequency using a well-maintained mower. This section provides a general overview of appropriate mowing practices for St. Augustinegrass lawns.

Mowing Height 

St. Augustinegrass lawns are generally best maintained at a mowing height of between 2 and 4 inches. 

Shorter mowing heights will require more frequent mowing to prevent scalping or injury to your turfgrass lawn. 

Mowing height may be determined by your cultivar and your mower’s capability. 

For St. Augustinegrass, it is recommended to set the mower at either the highest height of cut or one step below to allow for some flexibility. A taller mowing height will also offer several benefits, including shading out of weeds, deeper rooting, and improved water infiltration. 

Taller mowing heights are also recommended for St. Augustinegrass in moderate shade to increase leaf surface area and photosynthesis potential. 

Mowing Frequency

Mowing frequency is primarily determined by the rate of growth and the 1/3 Rule. Ideally, you should avoid removing more than one third of the total green canopy height at any one time. 

For example, if your optimum mowing height is 2 inches, then you should strive to mow before or by the time the grass reaches 3 inches in height. 

This prevents scalping and excessive injury that will compromise the overall health and appearance of the turfgrass. 

Furthermore, frequent scalping will increase the likelihood of weed encroachment by exposing the soil to sunlight that promotes weed emergence and growth. 

Your mowing frequency will likely fluctuate throughout the year in response to changes in environmental conditions that affect turfgrass growth, such as light, temperature and precipitation, as well as water and fertilizer inputs. 

 

Other Mowing 

Recommendations 

Keep mower blades sharp and clean between mowings to prevent the spread of turfgrass pests such as disease and chinch bugs. 

Because turfgrass clippings are rich with nutrients, it is often desirable to mulch clippings or return them to the turfgrass, provided that clippings are fine and evenly distributed. 

Avoid returning clippings during times of active disease and when weeds are flowering. Avoid operating heavy riding mowers on turfgrass when the soil is wet, to avoid ruts and soil compaction.

 For more information on proper mowing habits, please see Mowing Recommendations for Warm-Season.