In Flanders Fields, where ornamental trees and plants grow – Episode 3

Standing 13 metres tall is a shaded hall hosting a spectacular range of containerised trees for creating an instant effect.

The Flanders’ Agricultural Marketing Board (VLAM) invited FCI to see a cross-section of ornamental horticulture in the province of Antwerp and the Kempen, aka Campine. The final episode three takes us to Solitair Boomkwekerij in Loenhout and Belgium’s most prominent tree nursery, Boomkwekerij Arbor NV in Houtvenne-Hulshout.

The self-governing Flanders Region includes the provinces of Antwerp, East Flanders, Limburg, Flemish Brabant, and West Flanders. Ornamental horticulture geographically concentrates in East Flanders, with Wetteren and Lochristie being epicentres of nursery stock and flowering pot plant production, respectively.

In the province of Antwerp, nursery stock and potted plant growers are much more scattered. So, the tiny town of Lier, 20km east of Antwerp, is a great location to explore seven of the region’s leading companies. Because departing from Lier’s city centre, they are all within a 50km radius.

Solitair Boomkwekerij

Euonymus alatus with Muehleneckia growing under its canopy at Solitair Boomkwekerij.

Established in 1986 by Dirk Cools and José Anthonissen, Loenhout-based Solitair Boomkwekerij is a tree nursery with a reputation for containerised or root-balled trees and shrubs for supply to predominantly landscapers, garden designers, garden owners and local authorities. Today, Dirk employs his two daughters, Chloë and Valerie, their respective husbands, and a staff of 25 FTEs supported by scholars who carry out crop maintenance work during the summer.

The nursery is in the heart of the Antwerp Campine. Here, the fertility of the soil -sandy but humus-rich – and the temperate climate provide ideal conditions for growing a complete package of plants. On 130ha of partially leased land, Solitair grows trees and shrubs in various sizes, colours, shapes, textures, and patterns.

Humans are visual-oriented beings, and Solitair’s customers are no different. With this in mind, the Cools family created what looks more like an English landscape garden rather than a commercial tree nursery.

An impressive cluster of cloud-shaped Taxus. Chloë Cools is sales manager at Solitair nv.

Its landscape is dotted with stately Quercus ilex and hispanica, windswept Osmanthus x burkwoodii and slanted Quercus suber, alternating with vast parkland stretches.

Against the English Landscape Garden etiquette, this ‘nature in constant reflux’ includes geometrically designed Carpinus betulus, multi-stemmed Amelanchier and an impressive cluster of cloud-shaped Taxus. Surprisingly, the latter can be dismantled and replanted in any garden or landscaped area.

Standing 13 metres tall is a shaded hall hosting a spectacular range of containerised trees for creating an instant effect, including the pineapple guava tree, Feijoa sellowiana or Acca sellowiana, which, contrary to what its name evokes, is different from the common guava tree. But both are members of the Myrtaceae family. The hall’s front yard features another collection of pot-grown character trees, such as Euonymus alatus with Muehlenbeckia complexa growing under its canopy. Muehlenbeckia, an evergeen climber, produces masses of slender, interlaced stems, reaching 2.5-3m. Its small leaves are dark green and come in roundish, heart-shaped, oblong and fiddle-shapes.

Rustic and robust alike are jumbo beasts of concrete planters with macro bonsai Pinus. Solitair delivers pot and tree together or shipped individually throughout Belgium, mainly using low-loader trailers. More than half of their customers are within the country’s national borders, while the business attributes almost 40 per cent of its turnover to income from exports. The Netherlands, the UK and Ireland are the top three export destinations.

Solitair sources its trees from nurseries across Europe, while some plants hail from abandoned, derelict gardens or areas where they stood in the way of residential or business developments.

Rustic and robust alike are jumbo beasts of concrete planters with macro bonsai Pinus, amongst others.

Chloë says: “Among our oldest trees are three iconic 170-year-old Taxus trees, uprooted in Antwerp to make room for a block of apartments. Taxus occupy a special place as it was among the first trees to be grown by our father 30 years ago. He also grew vegetable starter plants in spring and summer and Christmas trees in winter to manage cash flow more efficiently, a prerequisite for newcomers in extensive specimen-tree farming.”

More specifically, Solitair combines extensive and intensive production practices. Trees are transplanted every three years on the field and given time and space to grow into resilient, strong-character trees.

February heralds the start of the new selling season; schedules are tight until June, with Chloë noting that the selling season is extended each year. “In June, we are still shipping many evergreens, for example. There’s a lot of pruning work in summer, and we need to water the plants. The autumn season starts in October and runs until the beginning of December. So we are kept busy all year round.”

Over more than 30 years of trading, the company has forged trust-based relationships with a range of landscapers, so there is no real need for offering plant warranties. Chloë notes, “Prices for exemplary trees can be between €1000- €7,500. So, specimen trees can indeed be an expensive investment. Fortunately, discussions on plant warranties are rare. Most of our customers have bought from us for many years and know how well we tend the trees. We mostly focus on educating the clients and encouraging them to install drip irrigation, as too much or insufficient water is the most common mistake. We also do our best to stay in touch with customers. If plant issues may arise, we ask them to send us pictures at the earliest stage so we can better identify the problem and offer solutions.”

Boomkwekerij Arbor NV

Arbor sells trees and containers together, primarily to garden centres.

Arbor, established in 1901, has become a household name in root-balled or containerised trees and shrubs and is situated over 15 sites in Houtvenne-Hulshout, all within a 25-km radius.

In Belgium, combined production areas span an area of 300ha, which adds another 200ha in the French village of Vicq, near Rambouillet.

At home in Belgium, the focus is on growing around half a million large specimen trees in the open and smaller trees and shrubs on a 40-ha container field. In France, Vicq grows only 280,000 large avenue trees. The latter are sold on the French market with tall plane trees among its strongest sellers. Overall, the company’s catalogue features more than 20,000 genera, species, cultivars, and types of plants.

Arbor is arguably Belgium’s most prominent tree nursery regarding volume and value market share. At the same time, within Europe, it finds itself in the excellent company of notable tree nurseries such as Vannucci in Italy, Bruns and Lappen in Germany, and Van der Berk and Ebben in the Netherlands.

Maurice van Dyck.

Third-generation Maurice van Dyck, the father of Michael, who is currently at the helm of Arbor, has fond memories of working with the late Vannino Vannucci, his in-depth knowledge and eidetic memory.

The pair frequently embarked on USA business trips together to purchase trees, with Italian-speaking Maurice serving as an interpreter for Vannino.

Language proficiency is critical at Arbor, which attributes 90 per cent of its turnover to income from exports to other European countries and Central Asia.

Phytosanitary measures and climate are the two most important factors the company considers before exporting. Before going global, there’s a good grasp of the laws governing exports, local phytosanitary regimes, customs duties, and tariff barriers. Maurice explains, “Naturally, we also consider in which climate our trees can thrive. For example, our product range is not heat and drought-tolerant enough to be sold in the Middle East.”

Russia accounted for 15 per cent of the company’s export sales until the country started its atrocious war against Ukraine. “There is virtually no trade happening with Russia. At first, we struggled to find alternative markets, but a strong demand within Europe – frequently exceeding the offer – enabled us to compensate for the loss.”

Reminiscent of the export boom to Russia is a futuristic, world-expo-worthy warehouse built by reputable Brussels architects more than a decade ago. “Its perforated steel walls allow light and air to reach the tree batches inside. The idea is to cater for optimum air circulation for at least two days so that canopies are dry and pots are wet when loaded into the truck. Over the years, the technique has proven itself, and even though Russian trade has come to a standstill, the warehouse now hosts shipments for Central Asian countries.”

While exporting to Russia, Tajikistan, Kazakhstan, and Uzbekistan may be an exciting and adventurous endeavour, the largest portion of trees sell much closer to home.

In Broadgate, a 32-acre central London neighbourhood, Arbor trees help to connect the worlds of finance, food, fashion, and culture. In Paris, a 12-metre-tall oak tree commemorates the city’s terroristic attacks in 2015. Also, Arbor delivered many trees for Paris’La Defense and tramways in France.

Landscapers, city councils, and garden owners make up the biggest chunk of the company’s customers, explains Maurice, adding that smaller trees also find their way to garden centres in

Germany and France.

Character trees mainly belong to the world of the wealthy. A castle owner once ordered a 70-year-old and 14-metre-tall Sequoiadendron giganteum whose 27 tonnes of rootball needed special transport and a police motor cart. The entire operation made the headlines. Arbor is committed to reducing its ecological footprint. Drip irrigation achieves optimum plant growth and quality in containerised nursery production while minimising water use. This closed-loop system is designed to harvest excess irrigation and rainwater and helps reduce nutrient leaching and pesticide run-off.

Previous summers have been scorching hot in Belgium, with an increasing need to pump up groundwater for irrigation. Maurice says the company is fortunate to own a permit to source quality groundwater from a 90-metre depth. He notes, “However, a needed second permit is still under review by the local water management authorities. A new law now allows only the food industry to use water from 90 metres deep, while we are no longer allowed to go deeper than 30 metres for our water. The problem, however, is water at such a depth contains too much iron and is not suited to irrigate our trees.”

Effective collaboration, concludes Maurice, is critical in maximising the potential across the nursery stock value chain, citing the bond between Arbor and Vannuci as a shining example. “For the planting alongside a tramway in Portugal, we delivered the deciduous trees while Vanucci brought in the Mediterranean trees such as Quercus ilex and Magnolia grandiflora. Modelling on more or less the same business model was the delivery of trees for the World Expo in Lisbon in 1990 when we teamed up with local tree growers from Portugal.”

This article was first published in the December 2023 issue of FloraCulture International.