Most people with an interest in gardening know that perennials can be propagated by dividing them up. But someone who knows much more about the propagation of perennials and the methods for doing so is doctoral student Tina Westerlund.
The horticultural students are on their knees, sowing vegetable seeds outdoors on this sunny but chilly spring day. They had spent the previous day working on the perennial beds, where they took cuttings with Tina Westerlund.
“The idea is that the students should come into contact with different propagation methods. What does the plant look like? What affects the choice of method? This is knowledge that they will need later on.”
We meet at the Department of Conservation in Mariestad, where Tina is a doctoral student and a member of teaching staff. Her research has focused on vegetative propagation methods, i.e. where propagation occurs through part of the plant forming a new plant instead of being grown from seed. She has charted methods by reading about them in literature from the 18th century to the present day, and by visiting plant nurseries around Sweden. She has also tried out some of the methods from the handbooks herself – sometimes more than once.
“By carrying out my own propagation trials, I’ve been able to address the issues in greater depth. This in turn has helped me in my communication with growers and when reflecting on propagation instructions. I’ve been able to ask questions in different ways after having tested the methods myself.”
THE AIM OF THE visits to the nurseries has been to take part in and carry out various “procedures”, as she calls them in her thesis. Tina wants to learn about the details in greater depth, which involves using all her senses. Being able to pull up, break off and cut the plant. Knowledge about plant propagation has often been handed down at the nursery, but the methods have changed over the years for one reason or another.
“In the past, plants were cultivated outdoors and then dug up when they were ready to be sold. Today, everything is grown in pots which affects root development. This could be one reason why propagation using root cuttings is not as common as it once was.”
As Tina explains, another reason is the nurseries’ working situation. It is not necessarily the case that nurseries will be able to take cuttings at the time when this is actually most favourable for the plant. For example, seasonal workers might not have started work yet, so cuttings may have to be taken a few weeks later. This can also affect the method itself and the choice of method.
PLANT PROPAGATION IN SWEDEN has undergone a dramatic reduction since the mid-20th century. One reason is the large-scale propagation industry that has emerged in Europe, selling plants to Sweden.
“Most of what is sold in Sweden is propagated abroad. Just because something is labelled as having been grown in Sweden, that doesn’t necessarily mean it’s been propagated here.”
One of the reasons why larger garden centres in particular now sell plants that have been propagated abroad is that they are simply unable to obtain the quantity of plants needed.
“This is to do with how we consume plants today. There’s a throw-away trend whereby we buy perennial plants that then end up in a pot and are discarded in the autumn, as it’s easier to buy new plants next year.”
Knowledge about plant propagation is based on long traditions, and when these are not practised to the same degree as before, there is a risk that the knowledge will be lost. This also means it is hard to retain historically interesting plants that are part of our cultural heritage. At the turn of the century, the Swedish parliament agreed on a national programme for cultivated plant diversity, as part of which cultural varieties of everything from currant bushes to perennials and vegetables have been collected. This has taken place within eight different inventorying programmes, with members of the public helping to find and describe the plants. The programme has also involved research, and Tina has had contact with Linnéa Oskarsson at the Swedish University of Agricultural Sciences, resulting in what has been dubbed the “perennial roll call”.
“We’re planning how to show older varieties of plants as part of our historic gardens, and to encourage an interest in preserving perennial gardens,” explains Tina. “One idea involves working with the gardener at Mårbacka to propagate a white-flowered harebell that the perennial roll call has received from Selma Lagerlöf’s garden in Falun.”
The programme has now entered an evaluation phase in which the collected materials are being studied, evaluated and DNA analysed. The next step will be to preserve the material in a gene bank, from which it will be freely available.
ONE OF THE CHALLENGES faced by Tina in her research has been finding documentation methods. Earlier descriptions often lack details, perhaps because they were seen as obvious stages in the process. But as this handed-down knowledge is now disappearing, the need for clear, detailed instructions is greater. At the same time, it can be hard to assimilate large amounts of text, as Tina herself has often found in her teaching. So new documentation methods are needed, for example using videos.
ANOTHER WAY OF spreading knowledge about traditional methods is via social media. A newly launched project at the University of Gothenburg’s Craft Laboratory has invited gardeners from historic parks and gardens to blog about their work. The initiative for the project was taken by Tina together with Joakim Seiler, a gardener at Gunnebo House and Gardens near Gothenburg.
“Gardeners have not traditionally been good at documenting their work. Many of them have kept dairies, but these are about varieties, numbers and results, and not about how they do various things. The blog will be a tool for discussing and continuing to develop gardening knowledge.”
JUST LIKE THE PROGRAMME for cultivated plant diversity, the blog is a way of preserving and sharing knowledge about our horticultural heritage. Many of those who currently administer historically valuable cultural sites lack gardening knowledge, and there is therefore a risk of valuable environments being lost.
“Parks and gardens are highly significant to our cultural environment, but the focus is often on the actual buildings. The gardens take second place, and there is a risk that gardening knowledge will disappear.”
Outdoor cultivation: growing plants outdoors in cultivated land on different scales, from small beds to large fields.
Cuttings: sections that are taken from a plant that then develop new roots and shoots when planted. These can be sections that grow above the ground or underground.
Perennials: herbaceous plants that continue to grow for more than one year. This group sometimes also includes plants with buds above the ground during the winter, such as lavender.