De Driehoek (Triangle) is an ecological Garden Park and an association of gardeners in het northeast of Utrecht. The grounds accommodate 137 private allotments where the members can cultivate their own vegetables, flowers or both. The terrain is characterized by two water courses left over of the original ‘polder’. On both sides of these ditches fruit trees of old fashioned races were planted at the time the garden park was founded. The grounds are sought after for a walk by the inhabitants of the home for elderly people next door and the residents in the neighbourhood.
The objective of De Driehoek is gardening in an eco-friendly way. In June 2012 the AVVN (Netherlands Organization of Hobby Gardeners) rewarded our efforts with four ****, the highest achievable rating. In 2016 this rating was confirmed. Obviously, eco-friendly management is a process rather than a status. The text below is a summary of a booklet we produced to give our projects a focus and to advertise our goals to our members and the wider community.
Traditionally, our individual allotments were lined with privet hedges. The new approach is to encourage more diversity in species and in clipping, while keeping the height restricted, so as to maintain an open aspect. Along parts of De Driehoek’s perimeter, we have built ‘dead hedges’. For living hedges/shrubs, we are changing over to a hedge-row style of management, with a focus on thorny and fruit-bearing bushes, so as to provide food and shelter for small birds, etc. We are experimenting with labelling trees and shrubs. We have four beekeepers, one of them also a tireless promotor of native bees. The bee chalet in our park – offering information, and examples of providing accommodation – was his initiative.
For a number of years, our central compost heap has provided grass snakes with hibernation spots and nurseries. Because of the heat generated in this sizeable mound, the snakes are well protected from frost in winter, while they find the ideal temperature for incubating their eggs in summer. The heap is turned well before winter, so as to minimize disturbance of the snakes’ life-cycle. However, we are encouraging composting on individual allotments, with suggestions on how to go about it.
We are developing low-maintenance perennial borders to show that a rich and colourful effect can be achieved with a mixture of bulbs, native plants and sturdy perennials. Using plants that are happy to be where they are – almost to the point of becoming ‘weeds’ – is part of eco-friendly gardening. Three of our very special inhabitants, grass snakes, bats, kingfishers, are welcomed at De Driehoek. Numerous nesting-boxes have been provided for smaller birds. We have provided a steep bank as a nesting spot for the kingfishers and we are looking into providing suitable hibernation possibilities for bats and hedgehogs. ‘Stinzenplanten’ were originally imported to beautify the grounds of stately homes, etc. These (mostly) woodland plants and bulbs take advantage of the sunlight that reaches the ground before the trees burst into leave. As harbingers of spring, they are welcomed by insects, as the first source of nectar in the season.
Water is an integral part of our park, sometimes to the point of submersion. A layer of heavy clay makes drainage difficult – a nuisance if you’re trying to grow potatoes or other sensitive crops, a joy if you ‘go with the flow’ and learn to appreciate the possibilities. Our main watercourses are part of a wider water management system. It is our obligation to keep them reasonably clean, to ensure water circulation. We are looking for ways to recreate the gradual slope that is so typical of natural watercourses, and so crucially important for wetland vegetation and wildlife. The banks are mown twice a year in June and September. The grass is removed to prevent nutrients from seeping back into the soil. We are experimenting with sowing meadow plants on bare patches, so as to increase diversity.
The use of any non-organic pesticides is strictly forbidden. Also, we strongly urge gardeners to limit the use of soap and detergent, use organic products only, and to make sure they don’t end up in the water. Some years ago, a grove of buckthorn (Rhamnus) was planted, a great shrub for bees because of its extremely long flowering season. We are aiming to increase diversity in herbaceous plants so as to attract more butterflies. We have built a ‘dry-stone wall’ to create different microclimates. Additionally, our stock of fruit trees along the two main watercourses are a source of pride, with a special working group dedicated to its management. We are re-introducing older varieties and share the fruit with birds and neighbours. The trees are labelled. Pruning workshops have been held, to improve our skills and expertise in this area.