Mediterranean grass species displace native varieties

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MARKET & CURRENT AFFAIRS

Frank van de Ven, Wednesday 27 August 2025

135 sec

'Anticipate mediterranisation'

The composition of Dutch grass fields has changed over the past decades due to the arrival of southern grasses. These Mediterranean species are more resistant to prolonged heat and drought than native ones. Gradually, these new grasses are gaining ground, affecting the overall composition of grass fields. But what does this 'mediterranisation' mean for the future, and how should we respond to it?

Climate change increasingly exposes grass fields to long periods of heat and drought. This results in brown patches and bare spots. Native grasses often cannot withstand these temperature extremes and consequently disappear. Southern grasses—well adapted to such conditions—take the place of the vanishing species. These 'newcomers' are often the only green plants in an otherwise scorched vegetation. The knowledge platform for floristic research in the Netherlands (Floron) has mapped out the consequences of mediterranisation.

Mediterranisation

When more and more C4 species appear, we speak of mediterranisation. According to Floron, that is now the case, as C4 grasses from southern regions are increasingly entering the Netherlands. These species thrive in (sub)tropical climates and require much less water than native grasses (called C3 species). However, C4 grasses need abundant sunlight to grow. Daytime temperatures must not drop below 12 degrees Celsius, but from June onwards, that is no longer the case here.

'With water scarcity in mind, it is important to carefully consider which grass species you use'

Explosive growth

As mentioned, mainly annual grasses dominate in southern Europe. C3 grasses are also increasingly being replaced by C4 grasses in these regions. The same is happening more frequently in the Netherlands from June onwards. The platform even speaks of an "explosive growth", but Steven Wiersema of \DSV Zaden\ sees it differently: 'We do not observe a surge of C4 grasses. Current C3 varieties suffice. In fact, these have been bred to perform far better in terms of sports-related qualities than other grasses. With C4 grasses, you are dealing with species that require a winter dormancy. That means you need to overseed, but in practice there is no time for that given the playing schedule.'

Research

Wiersema notes that climate change is indeed a hot topic in the sector: 'The green industry is delving deeply into its consequences. Research is being conducted, and machines and products are being developed to respond to these changes. Studies are examining how grass species react to rising and falling temperatures and/or drought. Different mixtures are also being developed that can be sown year-round.'

'If you want climate-adaptive solutions, you need to look beyond the official grass lists'

Detrimental to grass

Steunenberg confirms that the changing climate has altered the field: 'The maintenance of sports fields is vastly different from fifteen to twenty years ago. Changing weather conditions were the reason why two years ago we introduced a new overseeding method.'

Sow three times

Instead of sowing once in summer, Steunenberg advises sowing three times throughout the year: 'In today's summers, temperatures rise above thirty degrees, which is detrimental to grass. That is why we recommend overseeding already in early spring. In summer, you may choose to do an additional standard overseeding. What we strongly advise, however, is to overseed again in September, when soil temperatures are still high and moisture is sufficient. In more and more grass mixtures, we use a higher proportion of smooth-stalked meadow grass, as this species is more resistant to drought and heat.'

Smooth-stalked meadow grass

Olaf Bos of Barenbrug highlights resilient smooth-stalked meadow grass as an interesting, future-proof solution: 'Within a species—whether diploid or tetraploid perennial ryegrass, and certainly also within smooth-stalked meadow grass—there are enormous differences in behaviour and response to weather extremes. For example, how efficiently a plant uses water, and how it adapts to water shortages and to drought and heat stress. If you want climate-adaptive solutions, you must look beyond the official grass lists. Remember that not all varieties within a species can be generalised. You need to select varieties at cultivar level that form a strong team together.'

This article was first published on 27 August 2025 on the website](https://www.vakbladdehovenier.nl/article/51054/mediterraanse-grassoorten-verdringen-inheemse-soorten]website) of De Hovenier.

Landelijk Bureau FLORON

DSV zaden Nederland B.V.

Barenbrug Holland BV

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