Dog Tuff Grass: A New Turf Species?

Tony Koski, Extension Turf Specialist

African bermudagrass (Cynodon transvaalensis)

Beginning in 2014, I began receiving questions about a “new” turfgrass – being sold under the name Dog Tuff ™ African Dogtooth Grass. The sellers of this grass suggest that its Latin/scientific name is Cynodon hybrida.  I have searched databases for this grass and run it by prominent bermudagrass breeders and researchers – with no one recognizing any turfgrass (or grass, for that matter) with the Latin name C. hybrida.  For you plant nerds out there, you can check the validity of any scientific/Latin name at The Plant List, a working list of all plant species (currently contains over 1 million plant species names). If you want to be uber nerdy, you can even see a photo of the earliest specimen of this grass (housed in the herbarium of the Royal Botanic Gardens, Kew), collected in Africa in 1919. The species was officially named in 1921.

C. transvaalensis is a non-native grass, introduced
from the Transvaal region of South Africa.

Soooooo, this is far from a “new” grass. It is a species of bermudagrass, African bermudagrass (Cynodon transvaalensis Burtt-Davy), used by turfgrass breeders since the 1950s to develop new, interspecific turf-type bermudagrass cultivars. Tifway bermudagrass, released in 1960, has C. transvaalensis as one of its parents. African bermudagrass (AKA couchgrass, African dogstooth grass) is a native of the Transvaal region of South Africa, where it can be found growing on the high grass prairie (veld). This region of South Africa experiences sharp day (70s-80s)/night (30s-50s) temperature differences, and receives 18-24 inches of precipitation annually.

C. transvaalensis can produce a dense turf.

I have been growing this grass at CSU for many years, after finding it in a Denver lawn during the 2002 drought. It forms an attractive, dense sod. The leaves are very fine textured, and the grass spreads aggressively via stolons and rhizomes. It has excellent cold hardiness (one reason it is used as a parent in bermudagrass breeding programs). Left unmowed, it grows to a height of 3-6 inches, depending on how much water and fertilizer it receives. Because of its aggressive, dense growth, few weeds will appear in this turf. However, during the warmest times of the year, mowing will often result in scalping – causing a brownish appearance. Because of this tendency to scalp when mowed, it will probably look more attractive if left unmowed (or if mowed frequently…as in 2-3 times weekly during the summer).

Like all bermudagrasses, C. transvaalensis spreads
by aggressive stolons ('runners')

If this grass is so ideal, why don’t we see named cultivars on the market from breeding programs or sod producers – as is the case with other turf species? It’s because breeders recognize the limitations of C. transvaalensis as a turf grass by itself. It will tolerate very low mowing heights, but the tendency to scalp during the summer (even when mowed daily) is seen a as major impediment to using it as a turf on golf courses or for sports turf.  Its greatest value remains as a germplasm source for the breeding of cold-hardy, fine-textured, high-quality hybrid bermudagrasses. Those considering this grass should also be aware that it is a warm-season grass (like buffalograss), so it will green up sometime in May and become dormant/brown with the first hard frost in the fall.

Bermudagrass is one of few grass species that
spreads by both rhizomes and stolons - a growth habit
that makes it both a traffic-tolerant turf and a potentially
troublesome and difficult-to-control landscape weed

While some may find this grass useful as an aggressive ground cover for certain high traffic areas (dog runs, for example), it is important to recognize the potential for this plant to become a weed in the home landscape. In fact, the reason I found the C. transvaalensis that I currently grow at CSU is because of a homeowner request to ID a weed in their landscape. In recent years, one of the most common weed submissions (samples in the mail, or photos sent by phone or email) I receive throughout the summer is bermudagrass in home landscapes (lawns, shrub and flower beds, vegetable gardens) and on golf courses. In some states (including our neighbor Utah), bermudagrass is listed as an invasive species. In other words, be aware – if you decide to plant this grass – that is has the potential to spread into places where it might be unwanted. And…it can be remarkably difficult to eradicate…requiring multiple applications of glyphosate over an entire growing season.

Bermuda is a warm-season grass, so will have a long
winter dormant period in Colorado

So, yes, it is in many ways a tough grass – because it is bermudagrass. Remember: the perfect turfgrass (for every lawn situation) has not yet been discovered or developed by breeders. Every species has its positive and negative sides – and this one is no exception.