Save the garden during heat and downpours

The Dutch summer is becoming the last few years characterized by heat and drought records, scarce but heavy rains and flooding. You can immediately see the effects in the garden. It is no longer pleasant on the terrace in the summer heat – we prefer to sit inside. The grass changes color from fresh green to dried yellow. Some trees drop their leaves in an attempt to survive the drought. And when the rain finally comes, the water flows away over the hardened soil and the soil is hardly able to absorb any of it.

That can be done differently. The garden in particular can be a place to mitigate the effects of weather extremes. Tips for making the garden cool and resilient.

1 Less tiles, more green

About one third of the private garden area in the Netherlands consists of vegetation. Two-thirds is therefore covered with materials such as tiles, gravel and artificial grass. Hot summer days are harder to get through without nature in the garden. Stones retain heat, vegetation provides shade and evaporation just for cooling.

Another disadvantage of paving: “On tiles, rainwater cannot infiltrate the soil,” says Bart Zwiers, forester at Natuurmonumenten. “In the worst case, the rainwater flows through the tiles to the street, directly into the sewer. When it rains hard and the sewer cannot handle the pressure, it causes flooding in the streets, while our gardens dry out. To prevent both, you want to have rainwater in the garden as much as possible.”

Zwiers contributed to the preparation of a package of practical garden tips, which Natuurmonumenten free of charge offers. As a forester of De Onlanden nature reserve in Groningen, he knows how nature can help to deal with drought and flooding. During heavy rainfall, the Onlanden fills with water – thus ensuring that the inhabitants of the city of Groningen keep their feet dry. It is the largest and oldest climate buffer in the Netherlands. Nature and garden don’t have to be far apart, says Zwiers. “If you have a garden, you are in fact a nature manager. Take that role seriously.”

So limit paving in the garden to a minimum. A terrace does not have to be larger than the surface that is actually used. A narrow access path is often sufficient. A flower border can be sown in the places where the tiles have been lifted. Or wait and see what vegetation comes naturally. The rainwater can flow from the reduced terrace into the border.

You can make a border from the removed tiles to demarcate the border. Or stack them up into a bench or wall. Hedgehogs and insects, but also frogs, toads and salamanders will make grateful use of this – provided there is water nearby. Would you rather get rid of the tiles? Some municipalities offer a free tile collection service.

2 Collect rainwater

The rain that flows along the roofs usually goes directly into the sewer via the drainpipe. It is better to disconnect the downspout and collect the rainwater. “That is of course possible in a classic rain barrel,” says landscape architect and gardener Michiel Verheijen. But that is certainly not the only option. If there is less space, you can, for example, place a tank under the garden bench. You are actually sitting on your rain barrel.” The water pressure is less close to the ground, but is sufficient to water the vegetation low to the ground with a garden hose.

A lawn as dry as hay is far from dead

Michael Verheyen landscaper and gardener

Keep this water as a buffer for really dry periods. Watering needs to be done less quickly and often than many people think. Verheijen: “I understand that people prefer a green garden. But a lawn as dry as hay is far from dead. This usually clears up quickly after a rain shower.” If watering, do this preferably in the evening: “Then the least water evaporates and therefore most of it goes into the ground.”

In many municipalities there are subsidies for greening the garden, such as replacing tiles with vegetation or installing a rain barrel. The Green Subsidy Guide of Milieu Centraal is central which municipality offers what.

3 Create a wadi

Collected rainwater can also be led to a so-called wadi. This is a pit, or depression in the lawn, which is flooded during wetter periods.

Verheijen: “Suppose it is dry for a month. Soil life then has a hard time. When it rains again, the hard, dried-out soil has difficulty absorbing this water. It can then flow from it, just like with a terrace, to the street towards a well. While you want the soil to be able to absorb it completely, like a sponge.” A wadi helps with that. In it, water seeps quietly into the bottom. In this way, it replenishes the groundwater level and ensures a greener garden with less drought.

Dig a bowl in a lower part of the garden. It can be as large as desired: a wadi can also be excavated in a small garden. A wadi of one square meter and 20 centimeters deep can already buffer 200 liters of water.

Plant species such as valerian, yellow iris, marsh forget-me-not and meadowsweet. They can withstand fluctuations in the water level and periods of drought.

4 Build a pond

According to Zwiers, a pond is the ultimate addition to the garden. “A pond acts as a nursery. The insects that are born in it are the food for animals such as birds, salamanders and frogs. A pond, no matter how small, forms the basis for so much life around it. And not unimportant: in dry periods, hedgehogs and birds find a place to drink.”

If there is room for a large pond, you can easily build it yourself with a bottom of pond liner. A more natural variant consists of a soil of clay or loam. According to Verheijen, it is better to call in a specialist for this: “If it is not laid properly, it can start to leak.”

If you have little space, Verheijen recommends a mortar tub. Dig it in, making sure that the edge is just above the ground. “You don’t want dust and sand to wash in with a rain shower. That can upset the balance.”

Then place about three water plants in a bottom of sand and pebbles and let the tub fill with rainwater. Other life, such as frogs and even salamanders, typically emerge within months. In a larger pond, fish will also come naturally. “Herons take fish eggs by their feet,” explains Zwiers.