Ditch the Bricks, Grow Some Green!

Since its launch in 2020, the NK Tegelwippen competition has become a major event in the Netherlands, mobilizing thousands of citizens and dozens of municipalities. Organized by the Frank Lee creative agency, this event encourages people to replace the cobblestones, slabs, concrete and asphalt in their landscaping with plants, thus helping to combat climate change and heat islands and improve rainwater management.

In cities, a large part of the ground is covered with paved surfaces, preventing rainwater from infiltrating naturally. As a result, water accumulates, overloading drainage systems and increasing the risk of flooding. These surfaces also retain heat and release it gradually, raising the ambient temperature and accentuating urban heat islands. Finally, the reduction in green spaces reduces the habitats of insects, birds and other species, endangering urban biodiversity.

Tegelwippen or “Tile Flipping”

Tegelwippen, which literally means “tile flipping”, offers a simple and effective solution to these problems. By removing paving stones and other inert surfaces and replacing them with plants, shrubs or even vegetable gardens, citizens make their environment greener, cooler and better adapted to climate change.

NK Tegelwippen, which takes place this year from March 21 to October 31, works like a competition in which each city earns points based on the number of cobblestones removed, adjusted for the number of inhabitants. This system encourages small towns as much as large ones to participate actively. Citizens are invited to submit their results online by sending a photo of the pavers removed and the new green spaces. Rankings are updated regularly, encouraging municipalities to mobilize their residents to dethrone their neighbors. Some cities even organize special events and planting days to raise awareness and encourage collective action.

Since its inception, the initiative has removed more than 14 million paving stones, transforming hundreds of neighborhoods into greener and more livable spaces. The Netherlands, which faces significant climate challenges due to its geography, has found a concrete way to involve its citizens in urban adaptation.

Other countries are starting to take an interest in this innovative approach. The concept could be applied elsewhere, particularly in North America or Europe, where soil artificialization is a major issue. Tegelwippen shows that with simple local and collective action, it is possible to make cities more resilient and better adapted to future climate conditions, while having fun.

Tegelwippe at Home!

Even if there are no competitions in your region, why not have a go at tegelwippen at home?

Before you start, think carefully about which surface to remove. It is best to start with areas that are not used very often so as not to interfere with traffic and your daily activities. Also consider the needs of plants when choosing a location. Light is a determining factor, and plant species have varying needs. Although some plants tolerate shade, plant diversity is greater in sunny areas. Water is also a key element: surfaces under a roof overhang receive little rainwater and require regular watering. Water management can be optimized by redirecting a gutter towards the planting area, but there is still a risk of flooding or water infiltration near houses if drainage is inadequate.

Before Planting

Before planting, it is important to assess the available space and the adult size of the selected plants. A flower bed must be at least as wide as the mature plants. Planting a tree in an opening between the paving stones is not advisable due to space constraints and compacted soil.

The preparation of the planting hole must be carried out in several stages. The paving stones are removed one by one, also removing the gravel base that supports them. It is recommended to dig at a gentle slope, starting from the remaining paving stones, at a 45° angle to prevent the foundation from collapsing. A 30 to 45 cm (12-18 inch) strip of gravel should always be kept around the cleared area to ensure the stability of the remaining paving.

Useful Tips

The geotextile, often found under the paving stones, prevents the mixing of gravel and soil. It must be removed at the precise location of the planting to allow the roots access to the soil. A new layer of geotextile can be added on top of the gravel base that will be retained to maintain the structure. A border of paving stones or other support structure can be installed along the remaining paving stones to prevent them from moving.

Once the hole has been prepared, it should be filled with good-quality, well-drained planting soil enriched with compost, if necessary. After planting, lightly compact the soil around the roots to ensure they are firmly anchored and to prevent gradual subsidence.

Plant Selection

Not all plants are suited to the conditions of planting pits surrounded by paving and gravel. Limited access to water and nutrients, soil compaction and extreme temperatures impose particular constraints. It is therefore essential to choose plants that are able to thrive in poor, dry soil or, in the case of poor drainage, tolerate a temporary excess of moisture.

A percolation test can be used to assess soil drainage. Dig a hole about 30 cm (12 inches) deep, fill it with water and measure the absorption time. Well-drained soil drains water in less than an hour, while acceptable drainage is between one and two hours. Beyond that, species adapted to wet soils, but tolerate drought, should be favored.

Certain factors must be taken into account to ensure the success of the planting. In addition to the constraints related to water and nutrients, these areas experience significant temperature variations: they accumulate heat in summer and cool rapidly in winter. Moreover, in urban environments, the plants must be able to withstand de-icing salt, summer drought and soil compaction.

As with any planting, it is essential to choose plants that are suited to the light and the hardiness of the site. Careful selection guarantees better establishment of the plants and sustainable development despite the difficult conditions.

A Few Well-Adapted Plants

Ground-Covers

• Creeping thyme (Thymus serpyllum) – Aromatic, attracts pollinators, tolerates trampling. Zone 3, 4 to 8 USDA.
• Goldmoss tonecrop (Sedum acre) – Thrives in dry, rocky soil, minimal maintenance. Zone 3, 4 to 9 USDA.
• Wild strawberry (Fragaria vesca) – Edible ground cover that spreads well. Zone 3, 5 to 9 USDA.
• Saw Sedge (Sagina subulata) – A soft, low-growing alternative to grass. Zone 4, 4 to 8 USDA.

Perennials

• Purple coneflower (Echinacea purpurea) – Drought-resistant, attracts pollinators. Zone 3, 3 to 8 USDA.
• Woodland sage (Salvia nemorosa) – Prolonged flowering, drought tolerant. Zone 4, 4 to 8 USDA.
• Black-eyed Susan (Rudbeckia fulgida) – Resists heat and drought, long-lasting flowering. Zone 3, 3 to 9 USDA.
• Yarrow (Achillea millefolium) – Grows well in poor soil, excellent for biodiversity. Zone 3, 3 to 9 USDA.
• Cranesbill (Geranium macrorrhizum) – Robust, spreads well, low maintenance. Zone 4, 4 to 8 USDA.

Grasses

• Blue fescue (Festuca glauca) – Compact, drought resistant, ornamental. Zone 4, 4 to 8 USDA.
• Switchgrass (Panicum virgatum) – Adds height, tolerates poor soil. Zone 3, 5 to 9 USDA.
• Autum moor grass (Sesleria autumnalis) – Adapts well. Zone 4, 5 to 8 USDA.
• Tufted hair grass (Deschampsia cespitosa) – Tolerates various types of soil. Zone 3, 5 to 9 USDA.

Shrubs and Small Trees

• Alder-leaved serviceberry (Amelanchier alnifolia) – Edible, hardy berries. Zone 2, 2 to 7 USDA.
• Red-osier dogwood (Cornus sericea) – Ideal for erosion control, colorful wood in winter. Zone 2, 3 to 7 USDA.
• Ninebark (Physocarpus opulifolius) – Drought-resistant and attractive to pollinators. Zone 2, 2 to 8 USDA.
• Black chokeberry (Aronia melanocarpa) – Tolerates urban conditions well, attracts wildlife. Zone 3, 3 to 8 USDA.
• Chokecherry (Prunus virginiana) – Hardy, provides food for birds. Zone 2, 2 to 7 USDA.

Plantes indigènes et favorables aux pollinisateurs

• Common milkweed (Asclepias syriaca) – Host plant for monarch caterpillars. Other milkweeds can also be used. Zone 4, 3 to 9 USDA.
• Goldenrod (Solidago spp.) – Source of nectar at the end of the season, tolerates drought. Zone 3, 3 to 9 USDA.
• Beebalm (Monarda fistulosa) – Excellent for bees and hummingbirds. Zone 3, 3 to 9 USDA.

It’s Planting Time

When planting, it is important to leave enough space between plants to promote good root development and avoid excessive competition. However, too much space could allow weeds to grow.

The crown of the plant should be positioned slightly below the level of the surrounding paving stones to ensure stability. Once planting is complete, a thin layer of organic mulch, such as ramial chipped wood or shredded leaves, can be applied. This cover helps to limit water evaporation and reduce weed proliferation, particularly during the first year, while the plants adapt to their new environment.

Immediate watering after planting is essential to promote rooting. During the first year, it is recommended to monitor soil moisture and water as needed, especially in times of drought. The use of a soaker hose is particularly recommended in this situation.

Integrating plants to replace paving stones improves water infiltration, reduces heat islands and promotes biodiversity by providing a habitat for pollinators and beneficial insects. Transforming a paved surface into a green space contributes to the environmental resilience of our cities while embellishing our living environment.

So what are you waiting for? Ditch the bricks, grow some green!