Customer case

Prinsenhoftuin in top condition thanks to collaboration between Donker Groen and DCM

About this client

Name

Prinsenhof

Sector

Amenity/Public Green

Location

Groningen

The Prinsenhof in Groningen is widely considered as one of the city’s most beautiful green spaces. In 1569, the site was transformed into a palace for the first Bishop of Groningen and Drenthe. It later became known as the Herenhof when Stadtholder George Lalaing took up residence there, turning it into an official residence for stadtholders, including members of the House of Orange‑Nassau. In the seventeenth century, the adjoining Prinsentuin (Prince’s Garden) was created. Today, the Prinsenhof is a peaceful green oasis where visitors can escape the hustle and bustle of the city for a while.

Within the walls of this Renaissance garden, visitors can enjoy a rose garden, a herb garden, neatly trimmed hedges, colourful perennial borders and charming arbours. Landscaping company Donker Groen maintains the garden to a high standard throughout the year, supported by the expertise and products of DCM. Thanks to this collaboration, the Prinsenhof Garden remains beautifully maintained and inviting, providing an ideal setting for a relaxing walk.

Maintenance by landscape contractor Donker Groen

Jan Cazemier is project manager at Donker Groen in Groningen. In this role, he oversees maintenance operations and leads a team of about forty landscapers responsible for gardens, parks and other public green spaces throughout the city and surrounding region. The Prinsenhof is one of the sites under their care and is owned by the municipality. According to Cazemier, it is truly one of the standout projects within their portfolio. Donker Groen has been responsible for the garden’s maintenance since 2023, carrying out the work at CROW‑A level—the second‑highest quality standard for the design and maintenance of public green spaces in the Netherlands. A wide range of maintenance activities is carried out on a weekly basis, including weed control, pruning, tying plants, litter removal, fertilisation and watering when necessary. Although the garden covers only about 5,000 square metres and is not particularly large, its specific layout and design require a high level of attention and meticulous care.

Soil sampling for tailored product recommendations

At this site, soil samples are taken annually. The results allow fertilisation advice to be precisely tailored to the specific needs of both the soil and the plants. This way, the plants get the right nutrition and continue to grow healthy and strong. DCM explains: "In the Prinsenhof garden, we are working with different plant groups, each with its own specific requirements. We take soil samples from the rose beds, hedges, lawns and perennial borders and analyse the results. This includes both primary nutrients as well as trace elements. We also assess pH levels, salt content and organic matter percentage. All of these parameters are taken into account when formulating a product recommendation. For the Prinsenhof garden, with its diverse plant groups, this led to the selection of several different products and formulations. Our analyses showed that the soil contained relatively high phosphate levels, so the recommendation was to use fertilisers with a low phosphorus content. This all requires a high level of precision."

An active soil life for visible results above ground

Cazemier explains that the roses required additional support, as they were affected by nematodes. The first step was therefore to strengthen the resilience of the rose bushes. "In addition to their standard nutrition, we applied DCM SOIL-ACTIV. This product contains Trichoderma and Bacillus, beneficial fungi and bacteria that increase biodiversity and stimulate a more active soil life. We are now in the second year and are already seeing clear improvements." Positive developments are also visible in the hedges: they are growing healthily and their foliage shows a noticeably deeper green colour than before. "We continue to take soil samples every year, unless there is a specific reason to carry out additional measurements in between. In principle, DCM provides a year-round product recommendation, clearly specifying what actions are needed and when. Our landscapers are responsible for carrying out the fertilisation programme. If conditions become too dry, we adjust the schedule accordingly. And if no rainfall is forecast for a longer period of time, we take care of irrigation ourselves. In moist soil, nutrients and fertilisers are absorbed quickly, allowing them to do their job effectively."

Sustainable green maintenance

Donker Groen works entirely without chemical products. The municipality of Groningen also aims to manage public green spaces using only fertilisers and nutrition products with an organic basis. DCM's products align perfectly with this vision. That is why the municipality has chosen to work with DCM for both planting and ongoing maintenance of the municipal green areas.

DCM holds the Taking Climate Action label and publishes an ESG report (Environmental, Social and Governance), offering transparency about its performance and objectives in the fields of environmental impact, social responsibility and good governance. In addition, DCM’s ECOR products are approved for use in Dutch organic agriculture.

Both Cazemier and DCM's account manager regularly visit the Prinsenhof garden to monitor the development of the green spaces. They also work together on other projects in the region, but this project remains special to them. "You can truly feel the history here. During the summer months, many tourists and day trippers visit the garden, and local residents enjoy spending time here as well. It’s rewarding to contribute to the preservation of this green heritage and to ensure together that it remains in top condition."

DCM SOIL-ACTIV

Complete soil improver for laying out and renovating lawns. Indispensable when planting ornamental plants

DCM ECOR® 2

Organic: high potassium fertiliser.

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