Kilrea’s 8th Green Mystery: Greenkeeper’s Battle to Restore Turf

Gordon Rees, head greenkeeper at Kilrea Golf Club, reveals how he and his team dealt with a perplexingly problematic putting surface.

A seemingly inexplicable problem with one of the greens has been the focus of Kilrea Golf Club’s greenkeeping team in recent years.

Despite boasting greens of an impeccably high standard, one has stubbornly under-performed. The actions taken to deal with the loss of turf on Kilrea’s 8th green serve as a reminder to all greenkeeping professionals that focussing on the basic fundamentals of turf management can go a long way towards overcoming most challenges.

The background

To understand fully the reasons for this particular issue, some background information on the 8th green and the surrounding area is required. The green was constructed in the mid-1990s as part of a redesign of the previous short par 4, extending it to its current 402 yards. While this certainly brought improvements in terms of golfing strategy, the environmental conditions around the green were far from ideal. Tall oak trees dominated the right and rear of the green, while self-seeding birch trees gradually encroached into the previously open area of heather on the left. These trees severely restricted light and air movement, while a steep bank to the right of the green often caused water to collect on the surround and along the right side of the green itself.

Moreover, the quality of the root-zone material used in the construction of the green was poor, causing further drainage problems, and the presence of stones approximately 150mm below the surface made deep aeration work difficult. In spite of these problems, however, the green gradually improved over the years, benefitting from an ongoing aeration and top-dressing programme. The hole was also popular with members, who recognised it as a significant upgrade to the previous layout.

Particular challenges

Given the less favourable conditions around the green, some challenges that were not present on other greens were to be expected. The green was significantly more prone to fungal disease, particularly Microdochium. It has been the club’s policy to avoid using fungicides but this green tended to be the exception. Even so, there had been periods of significant disease scarring, notably over the winter of 2014/15. Leaving disease issues aside, the turf often experienced significant winter thinning. This was particularly obvious in 2019/20, but the enforced closure in the spring of 2020 due to the Covid pandemic allowed time for overseeding and recovery.

There followed some fairly minor disease issues in the autumn of 2020, but throughout 2021 the green performed well, with the damp, shaded surroundings helping to offset any drought problems during an unusually dry Irish summer.

Over the winter of 2021/22 the green was rested during wet or frosty spells of weather, with the original short par-4 green reinstated as a temporary measure. As a result, the 8th green entered the spring of 2022 in improved condition. Sward density in late March and into April was better than in previous years, while some Microdochium scars from winter fungal activity were overseeded with a 100% fescue blend and were recovering well. The spring of 2022 was a good one for growth. The other greens on the course were making rapid progress, in contrast to the situation during the previous cold, dry spring.

Lagging behind

However, while the rest of the course was experiencing the transition from winter to summer, it was clear from mid-April that the 8th was lagging behind. Given the unfavourable environmental conditions in the vicinity, this was not in itself an immediate cause for concern.  By early May, however, the situation had deteriorated, with some yellowish patches of up to 250-300mm observed, mainly on the right half of the green. These patches were irregular in shape with no clearly defined perimeter and did not conform to the pattern of any common fungal disease. Anthracnose, which was initially suspected, was quickly ruled out. 

As the month of May progressed, these yellow patches gradually took on a darker appearance, with smaller sections coalescing and leading to loss of turf, which assumed a matted, black character. The green is predominantly bent grass with some Poa annua and fescue also present. In the bare patches, all three species were affected; any surviving grass was fescue. Remarkably, the left half of the green was almost completely healthy, in fact, this section was actually in much better condition than had been the case in previous seasons.

Expert advice

Since the problems affecting the 8th green did not resemble any of the routine diseases and disorders of turfgrass, expert advice was sought. Agronomist Dr Ian McClements examined pictures of the green and the problem patches and suggested testing samples for nematodes. Laboratory analysis was inconclusive, although it was suggested that the problem may have been partly due to nematode activity over the previous winter. 

With no definitive answer, the main focus of attention shifted towards immediate remedial action. Height of cut was raised to 6mm to allow overseeding and recovery of the affected areas and to ease the pressure on the left side of the green, which would have to accommodate the majority of pin placements for the remainder of the season. Inputs of seaweed, iron and nitrogen were increased. Overseeding work commenced in late May and was repeated in each of the next four months. 

In keeping with the general course policy, a straight fescue mix was used. Germination was good and the affected areas began to thicken out. Recovery of the existing grasses was initially disappointing, but improvement was noted from mid-June onwards. Some less desirable Poa annua and coarser natural grasses also crept into the previously bare areas. This was due in part to a reduction in the use of groomers and a suspension of verti-cutting operations to enable the newly germinated seed to become established.

By mid-August, sward cover had improved to the extent that it was difficult to discern from a distance which areas had been affected. However, closer examination revealed that the lack of verti-cutting and grooming, while necessary to allow new grass to establish, had also contributed to significant lateral growth in the previously thin patches. Two passes with the verti-cutting units set at a depth of 1mm in late August and early September helped to alleviate this issue but also revealed some small areas where no new seed had taken. These were overseeded manually in September and again in October.

Preventing reoccurrence

With overseeding work on these small patches in hand, the green had almost fully recovered by the end of October 2022. Attention then switched to ensuring there would be no repeat of the previous difficulties. But how could this be achieved when there was no definitive conclusion as to what had triggered these problems in the first instance? 

It is well known that some greens will stand up better than others when faced with the same physiological challenges. For example, two greens experiencing similar levels of leatherjacket infestation will not necessarily experience the same impact on sward density. The same applies to various other problems, including drought, fungal activity and high levels of foot traffic. Greens which are in better condition to start with will be under less stress and, therefore, better able to cope with any additional pressures. This line of thought was applied to the challenge of preventing future turf loss on the 8th green.

Regardless of whether the exact cause of the problems of 2022 could be conclusively established, it was, nevertheless, evident that the unfavourable environmental conditions in the vicinity left the green poorly equipped to withstand the extra pressure. This was a green already under stress due to high shade levels, poor airflow, limited depth of good quality rootzone and an expectation of year-round play with the ensuing level of compaction. Addressing some of these issues would help to ensure that the green would be better placed to withstand any pest or disease activity. This involved both long-term and short-term measures. 

Comparable condition

The green was not used over the winter of 2022-23. Previously the temporary green was only brought into play in cases of frost or waterlogging. Additional passes with the verti-drain were also scheduled, with six carried out in the year between October 2022 and 2023. Seaweed, sulphate of iron and sulphate of ammonia applications were carried out more frequently than on other greens. 

Overseeding recommenced in spring 2023 and continued on a monthly basis. Again, this was more often than was the case with the other greens. These measures had the desired effect and by the autumn of 2023, the 8th green was in comparable condition to other greens on the course. Over the winter of 2023-24, in addition to routine aeration work, a programme of long-term improvements to the environmental conditions at the site began. The removal of large oak trees is always a contentious issue with club members but, given the obvious impact they were having on the playability of the green, it was accepted that some thinning out was essential. Nearby birch and ash trees, which would have succumbed to ash die-back in any case, were also felled.

By allowing crucial sunlight and airflow to reach the green, the removal of these trees had a clearly discernible impact on sward quality. This helped the green to perform well over the main 2024 playing season, with sward density by this stage very similar to that found on the other greens. 

In conclusion

Reflecting on our experiences with the 8th green over the past two-and-a-half years has led to a reassessment of our approach to overcoming such challenges. When confronted with a ‘new’ problem, greenkeepers instinctively look for a ‘new’ explanation. Hence the initial focus on nematode activity, something which had not previously been an obvious issue at Kilrea; viewing the loss of turf on the 8th green as a ‘new’ problem, we thought that nematode damage might provide an explanation. 

While a definitive conclusion as to the exact trigger for our loss of turf proved elusive, the likelihood is that the problem had its origins in the poor environmental conditions in the immediate vicinity. Already less than ideal when the green was constructed, conditions had gradually deteriorated as the trees grew taller. Such changes are often difficult to discern when one is working on the site on a daily basis – we sometimes do not appreciate the very gradual changes.

The principal lesson we took from the experience was the importance of managing local environmental conditions. It really is no surprise that sunlight and airflow play such a huge role in the maintenance of healthy putting surfaces.