What are those Purple Spots?

First, let me say, No . . . Harold and his purple crayon did not pay a visit to our golf course.  Remember this classic book from your childhood?  I read this to my three-year old son Knox at bedtime last night and in the book, everything is purple.  Kind of like those funny looking spots on our greens and fairways.



Anthocyanin pigmentation on a green 


I thought I would take the opportunity to explain what exactly is causing these spots to suddenly appear as of late.  This phenomenon is brought on by swift temperature changes between day and night or mild weather followed by colder periods.  Sounds a lot like our weather in March and April doesn't it? 

Typically, our turf is green thanks to a pigment inside the plant called chlorophyll.  However, when we experience fluctuating weather patterns, another pigment called anthocyanin temporarily replaces cholorophyll as the main pigment in the turf.  This pigment is found in many other colorful plants throughout the plant kingdom such as the purple petunias that we hang around the clubhouse in the summertime or the red geraniums on your back patio. 

Anthocyanin pigmentation on a fairway.

Not all grass plants demonstrate the effects of anthocyanin as it can be limited to certain bio types of turf (we have thousands upon thousands here at TPCSR) which becomes even more apparent as the changes in pigmentation kick in.  Those biotypes that turn purple are producing sugars in the leaf on those relatively warm, bright sunny days.  However, when night rolls around, temperatures drop significantly and the plant is unable to move these sugars down into the plant.  With these sugars stuck in the top portion of the plant, they bind to our friend, anthocyanin and displace chlorophyll (the green pigment) causing the turf to temporarily turn purple.

This biological phenomenon does not harm our turf and is simply a part of Mother Nature's quirks.  It is also interesting to note that these spots tend to appear with stronger intensity on our more exposed areas which makes sense because these areas experience the greatest temperature fluctuations.  (Think wide-open North end putting green versus sheltered #2 green).  Once the weather patterns stabilize towards May and June, chlorophyll will once again become the main pigment in our turf.