Winter Injury Guide

I have put together a quick little guide book for our membership to understand some of the winter turf injury sustained on the golf course this season.  Some of the injury is intentional, some is desired and some is not. Either way the guide shows in basic terms what each injury looks like and the cause of it.  Sometimes  Mother Nature provides the best selective herbicide on the market. 

Winter Injury Guide

Crown Hydration:  Occurs when large amounts of surface water from snow melt turns into ice crystals outside the plant cell (extracellular) of the Turfgrass crown tissue. As these ice crystals form and enlarge, they pull water out of the cell, which will result in dehydration. At some point a dehydrated cell and cell membrane stop functioning and the result is cell death. Many times superficial damage occurs but If enough of the cells in the crown of the plant die, the entire Turfgrass plant will die as a result.

Figure 1 Hole #5 1st Fairway Under Trees

Figure 2  Hole #6 Fairway and Rough Sheet Water Flow Areas

Desiccation: Winter desiccation is the death of leaves or plants by drying during winter when the plant is either dormant or semi-dormant. Desiccation injury is usually greatest on exposed or elevated sites and areas where surface runoff is great. Tree root completion for water also affects the quality of the Turfgrass.

Figure 3 Hole #7 Exposed South Facing Mounds

                                                                   

Figure 4 Hole #4 Tree Root Competition For Water

Selective Herbicide Kill: Selective herbicides kill specific targets, while leaving the desired turf species relatively unharmed. We are using both older and newer chemistries to control Poa Annua in our key playing areas.

Figure 5 Hole #7 Fairway Poa Kill

Figure 6 North Chipping Green PoaCure Trials

More Is Better

Now that the greens have begun to actively grow, the areas in which Poa Annua was lost to Crown Hydration are easily identifiable. We are fortunate to have relatively small populations of Poa on our twenty five year old greens.  This has resulted in small circular areas of damaged turf that can be more quickly re-established than larger sprawling areas of  turf loss.

Aside from increased fertility levels and the use of PGR's to promote  increased tillering many of these spots have been overseeded with Bentgrass. Full scale broadcasting of seed has taken place throughout the greens with even more specific work being done to the small spots.  The seed that was broadcasted was spiked into the soil surface to increase soil to seed contact which is vital for germination.  On top of that a divot mix that included Bentgrass seed was also applied to these thin areas to further improve the germination likelihood.  This sand mixture also serves another purpose in keeping the green surface smooth because some of these dead Poa areas are slightly sunken below the turf line.

As existing Bentgrass moves laterally and germination of new seed occurs the putting surfaces will still roll true even though adequate turf might not exist.

Close Up Of Dead Poa With Bent In The Middle

Sand And Seed Mixture Applied To The Voids

A New Beginning

The damage that was incurred throughout the course from the March snow storms is being methodically repaired.  The fairway areas that were damaged are being overseeded during aerification which will help establish the proper turfgrass species in these problematic areas.

The greens are being overseeded as well to encourage new Bentgrass growth in some of the newly created voids from the dead Poa Annua.  Not all of the Poa is totally dead and some regrowth is occurring which will help with the overall recovery of the turf.  Ideally the Poa will stay inactive and the Bentgrass seed will germinated and allow new seedling to become established.

Most of the greens have minor damage on them with the exception of the greens on #4 and #10.  Rather than fight a long re-establishment period on the tenth green, I decided to bite the bullet and re-sod the entire green. Although not ideal this is the best thing that can be done to get the green back in play as quickly as possible. The green will be mowed at a higher height of cut for several weeks before being slowly brought down to match the other greens.  Throughout the years the green will receive additional care such as increased fertility topdressing and aerification all to help with the elimination of seams and help with establishment.

The Tenth Green Ready For New Sod

Sod Going Down

Back In Play The Next Day

A Tough March

The golf course was showing signs of coming out of the winter without any problems in early March, but then the snow came.  In March alone we had over three feet of snow that caused some late winter damge to the golf course.

The areas that were primarily effected were ones in which poor drainage and surface water flow occurs on the turfgrass.  These areas can be seen on greens, fairways and rough.

The primary loss of turf occurred to the Poa Annua and some Ryegrass. Losing both of these species of turf is good for our long term agronomic programs, but it has made some areas on the course look worse than they are.

The technical term for what occurred is called Crown Hydration. The process is complex, but it involves water freezing in open spaces around individual plant cells in the crown portion (growing point) of the plant. The ice crystals forming around the plant cell pull water out of the cell causing dehydration inside the cell. The process causes irreversible damage to cell membranes and death to the individual cells. A hardened plant can tolerate this condition, but once a plant loses hardiness (a natural occurrence in late winter) individual cells lose the ability to combat the dehydration process and severe injury can occur. The process is still not fully understood but damage seems to be worse when certain environmental conditions are met.

CONDITIONS NEEDED FOR CROWN HYDRATION DAMAGE TO OCCUR

Crown hydration damage usually occurs when warm temperatures are followed by quick drops in soil temperatures below . Hardiness of plants are generally reduced at this time when exposed to thawing. Free moisture (usually from melting snow or precipitation) around the crown of the plant freezes and draws water from the cell. This form of winterkill is more likely to occur in early spring once the snow begins to melt and there is excessive moisture present. Exacerbating this problem can be low-lying areas where water sits, poor drainage, and heavy soils.

I believe this damage occurred in the first two weeks of March when the heavy snows melted quickly during the warm daytime temperatures which were followed by cold freezing nights.  In this time period there were days in which temperature swings of more than 45 degrees ocured in a 24 hour period of time.

We will be addressing the damaged areas individually and use the appropriate method for repairing these areas whether it is sodded or seeded to best put the area back in play.