I've explained much of the following in previous blogs since the winter of 2011. For the benefit of all, especially those who have just recently started reading the Turf Care Blog, it is important to have at least a basic understanding of your golf course. Our greens are composed of two unique turf species, creeping bentgrass and annual bluegrass. Many of you know annual bluegrass as Poa annua or just "Poa". There are volumes to say about how and why we have these grasses on our greens. I only want to discuss adaptation to our winter climate. Creeping bentgrass survival rate far outweighs that of annual bluegrass and there is pretty much nothing we can change about that. The only thing we can do is modify the environment. An example would be covering a green with bubble wrap and an ice shield and then exchanging air under the covers throughout the winter. This is done to prevent ice buildup, a condition that is harmful to both bentgrass and Poa depending on how long the ice remains on the surface. We've done this on #6.
Fortunately bentgrass left to its own devices can tolerate upwards of 120 days of ice cover. But unfortunately Poa can't. In my experience continuous ice cover of 40 to 60 days is enough to kill the plant resulting in that dark green color (fool me once) and sickly sweet odor after the ice is removed or melts off the surface of a green. Various techniques are utilized to try and remove ice when the number of days begin to creep towards the lethal limit. These procedures come with a host of problems, the least of which is exposure to the most brutal unpredictable months of our winter here in central Alberta.
The second issue we now have to deal with is how each of these two turfgrasses will break dormancy in early spring. Too keep it simple, Poa annua will do it quickly and begin to take up water as soon as it is exposed to warm temperatures and daylight. Bentgrass on the other hand will stay dormant longer. When this occurs in March the potential for very cold weather following a warming trend leaves the Poa very vulnerable to freeze/thaw cycles that can shatter the plant cell wall leading to death. That is why we prefer to keep the Poa (and bentgrass) dormant as long as possible. Leaving the snow on usually helps at this time of year.
This past winter was not ideal for our course. We experienced several very warm and windy periods that led to reduced snow cover. Even though we had a fairly decent layer of snow the temperatures were high enough to cause extensive melting. Water is heavier than snow and it could only go in one direction. Down. Down to the surface in a few areas. Of course the weather changed and severe cold retuned leading to ice formation. I surveyed all the greens in mid February as reported in my last blog. Yes we have ice in areas as suspected. I also found healthy turf as well. We did clear the putting green before this last cold spell and the Poa is damaged on the east third of the green. Just as I thought it would be. It had ice on it in early January so we saw no harm in exposing it early. It still remains to be seen as to how we will fare on the rest of the course. Read my previous blog to see the areas we are concerned about. We should have a good idea how the course wintered by the end of next week assuming the weather forecast remains positive. Until then all I can say is have patience.
Wade
