An introduction to grass species for golf courses

Alistair Dunsmuir
By Alistair Dunsmuir May 10, 2012 16:29

An introduction to grass species for golf courses

At its simplest, the choice of grasses for golf greens is bentgrass, red fescue or a mixture of bentgrass and red fescue.

This is what you may choose but do not necessarily get. In many long-established golf greens the dominant grass is often annual meadow-grass, with odd patches of Yorkshire fog and perennial ryegrass. These three grasses make up the bad and the ugly.

Why would I want to classify grasses as good, bad or ugly? My short answer to this would be because they are! To expand on this we need to consider the characteristics and capabilities of the grasses.

In doing this I hope to provide a simple guide to help identify and appreciate the varying characteristics of these different grasses.

Starting with the bentgrasses, there are four species used on greens. These are browntop bent, creeping bent and velvet bent.

Confusingly, there are two types of browntop bent. If you start to dig here you need to know if you have Highland bent.

This grass is classified as a different species to other browntop bents and is markedly inferior in a golf green environment. There are a number of different cultivars of what could be described as the finer browntop bents.

For clarity, a cultivar is a cultivated variety. Along with species’ differences there will be cultivar differences. So when choosing grasses there is a need to consider both choice of species and choice within species. The choice within species (a number of different cultivars) can be large for some grasses and can get into the hundreds. This is not necessarily the case for golf green use but there are still 23 different cultivars of the fine browntop bents to choose from. You can find these listed in the 2012 Turfgrass Seed booklet.

This booklet collates results from long-term tests at STRI for different grass species and covers a range of uses. Choosing cultivars often comes down to price and performance, and it is the way of the world that better performance costs more. Here the phrase ‘do not spoil the boat for a half pence of tar’ comes to mind. Seed is a small component of the total maintenance budget. However, a small saving could have big negative effects. And, could end up costing more money!

If the surface is not up to scratch members could go elsewhere, if the surface is more disease-prone and less able to withstand traffic management, costs will go up. Finishing off with the choice of bentgrass species, there are 13 cultivars of creeping bent and four cultivars of velvet bent to choose from.

The bentgrasses as a group tolerate close mowing and are capable of producing very good playing surfaces, if the better cultivars are used. Traditionally creeping and velvet bent are sown as monocultures and browntop bents in mixtures with fine-leaved red fescues. At this point it is appropriate to mention the red fescues.

For golf greens there are two types, which fall into different sub-species groups. The common names for these groups are Chewings fescue (named after a Mr Chewings) and slender creeping red fescue. Like the bents, there is a range of cultivars within each of these groups. We list 45 cultivars of Chewings fescue and 39 cultivars of slender creeping red fescue for greens’ use in the 2012 Turfgrass Seed booklet.

Red fescues are very fine-leafed grasses where the leaves are often described as being needle-like. If you look very closely, the bentgrasses will have fine small leaves with a distinct flat blade. The bentgrasses also tend to have a dull appearance that contrast with the shiny leaf blades of the red fescues. The attributes of these grasses vary.

Comparatively the bentgrasses will tolerate close mowing better than the red fescues. The red fescues as a group have better tolerance of drought, an important characteristic if water use is restricted. Some of the red fescues, particularly slender creeping red fescues and creeping bents, are more tolerant of salt spray which would damage other grasses.

The red fescues will also perform under relatively low nutrient levels. This is something often exploited to control the ingress of weed grasses that require higher fertility conditions. It is beyond the scope of this article to go into great detail here. However, generally the art to getting the best out of the good grasses is to understand their characteristics and then manage them to exploit their strengths but not expose their weaknesses. In this regard do not expect red fescue to tolerate mowing at 4mm or lower for prolonged periods; or bentgrasses, with the exception of velvet bent, to produce a good surface under drought conditions.

What about the bad and the ugly? Here it is appropriate to mention annual meadow-grass first. Few people would purchase this grass but many have it. In a greens’ context it is often the dominant grass. It would be fair to say that you can get a very good playing surface with this grass but it will not last forever. What is bad is that it’s like a drug habit.

It will want more and more from you and ultimately will give you less back and let you down. As you pander to this grass’ excessive needs it will out-compete the less-demanding finer golf grasses. Once the process is complete you will be an addict with an expensive grass maintenance habit. You can look forward to increasing disease, thatch and drainage problems. Kicking the habit will also be a painful process and could take many years.

Annual meadow-grass – the plant – can be quite variable in appearance. A big giveaway is seed heads that occur all times of the year. In late spring / early summer there can be flushes of seed head production that markedly affect the appearance of the surface – it can look white in places. If you can see a seed head on the grass in close mown turf it is highly likely that it is annual meadow-grass. Compared with bentgrasses, annual meadow-grass tends to be lighter green in colour.

If you look very closely at the tips of the leaf blades these will be boat shaped. In contrast, bentgrass leaves taper to a fine point. You should struggle to confuse the fine needle-like red fescues leaves with the coarser more flattened annual meadow-grass leaves.

Turning to the ugly, we need to consider perennial ryegrass and Yorkshire fog. These grasses tend to be more unevenly spread and do not tend to dominate the surface. However, Yorkshire fog can form fairly large patches that can reach one to two metres in diameter. These patches stand out both in texture and colour. The patches are light green and the plants within them are fairly coarse compared to other grasses you would find in golf greens. If you look at the Yorkshire fog leaf blade closely you will notice that it is very hairy.

On damp mornings dew sticks to these hairs and there will be a noticeable difference between the wetter Yorkshire fog patches and the other areas of the green. This grass can be quite disease-prone and will affect (slow) ball roll where it occurs.

Perennial ryegrass is darker green and stands out because it grows more rapidly than other grasses. It can also be difficult to cut cleanly. This will leave ragged leaf blades that contrast with the other grasses. A close look at the leaves will reveal a very shiny back and a distinct ribbed upper surface. One of the big giveaways is a red base to the plant if you pull it out, which is not such a bad thing to do! In very close mowing regimes some cultivars of perennial ryegrass can produce an attractive surface.

However this surface will not last, over time it will thin out leaving gaps that will fill with moss, weeds or weed grasses.

Hopefully the descriptions above will help you to recognise the good and understand the long-term work in place to avoid the bad and the ugly.

Dr Andy Newell PhD is the STRI’s head of turfgrass biology

For advice about keeping golf course grass healthy read this: https://www.twl-irrigation.com/golf-course-lawn-maintenance-tips/

Alistair Dunsmuir
By Alistair Dunsmuir May 10, 2012 16:29
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  1. (@GCM_mag) (@GCM_mag) May 10, 16:32

    An introduction to grass species on golf courses: http://t.co/RpMNQApS

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