Transitioning perennial ryegrass out of couch

Sorting the couch from the rye.

By Bradley Tennant - The Igfh Team

Welcome to our new column Turf Talk presented by the International hub for greenkeepers, groundstaff and volunteers. Our aim is to unite greenkeepers, promote the industry, and help share the art of greenkeeping with others. The organisation is made by greenkeepers, for greenkeepers. We’re a group of dedicated greenkeeping experts who are on a mission to share our knowledge and passion with the rest of the world.’ Bradley Tennant – International Greenkeepers For Hire

Couch (Cynodon spp.) is commonly overseeded with perennial ryegrass (Lolium perenne) for reasons such as aesthetics, increased wear tolerance and to protect the couch once it enters dormancy.

The aim is to maintain this cover during the cool season months and then once it begins to warm up in the spring remove this to enable the underlying warm season couch to grow unimpeded. Increasingly problematic has been getting this ‘’transition’’ to occur smoothly as improvements in perennial ryegrass breeding have led to ryegrass becoming much more heat tolerant and consequently tending to hang on rather than keeling over once temperatures increase.

This is a cause for concern as research has shown that the couch requires approximately 100 days without ryegrass competition in order to achieve maximum performance.

Over the years new varieties of grass have become tougher, meaning that your old natural transitioning techniques may not work meaning you may have to use a selective herbicide.

Otherwise you may end up with residual ryegrass that can often be seen in clumps over the playing surface.

The speed of transition – using the appropriate chemicals also plays a major role in deciding when they should be applied. A faster acting chemical should be applied as late as possible into the spring unless a dormant looking couch is acceptable. Slower acting options, which can take up to eight weeks to work in contrast, should be applied much earlier in the season.