Blog: Marimurtra alive

On 6 and 7 November 2025, the Marimurtra Botanic Garden took part in the 5th Meeting of the Education, Outreach and Communication Group of the Ibero-Macaronesian Association of Botanic Gardens (AIMJB), held at the Botanic Garden of the University of Valencia.

The Education, Outreach and Communication Group aims to promote joint work among botanic gardens in the fields of science communication, environmental education and public engagement, sharing resources, strategies and experiences to bring botany closer to society.

During the meeting, the new coordinating team of the group was presented, formed by Anna Sans and Jaissa Obré (Marimurtra Botanic Garden), Guillermo García-Saúco (Castilla-La Mancha Botanic Garden) and Eva Pastor (Botanic Garden of the University of Valencia). The work of Blanca Olivé (Real Jardín Botánico Juan Carlos I) was also acknowledged, as she has led the group in recent years.

The meeting included an analysis of the current situation of the education and communication departments of botanic gardens, presented by Blanca Olivé, as well as the presentations of 15 member gardens of AIMJB from Portugal, Spain and Gibraltar, who shared projects, challenges and working approaches.

Throughout the programme, new proposals and action lines were discussed to strengthen collaboration among gardens, which were later voted on to establish working groups that will lead them in the coming months. A participatory activity in the garden was also carried out, focused on the concept of plant awareness disparity, as well as several debates on scientific communication and outreach.

Finally, the AIMJB Assembly was held, bringing together representatives of the gardens to address internal matters and define the general guidelines for the future of the network.

What happens to the leaves in autumn: the intelligent strategy of trees

The change in leaf color during autumn is not an accident but a perfectly programmed process by plants. When you walk through the Marimurtra Botanical Garden these days, you can witness this fascinating natural phenomenon.

But why does it happen exactly?

The key trigger is light. As the days get shorter, the plant detects that the hours of sunlight are no longer sufficient to maintain photosynthesis —the process that turns light into energy— efficiently. It’s time to stop the machinery of the leaf and prepare for winter.

Priority: recycle

The first thing the tree does is not to change color, but to “move out”. Before shedding its leaves, the plant begins an active process to recover the most valuable nutrients they contain, especially nitrogen and other essential elements. These compounds are transported to the branches and roots, where they are stored as reserves. This is the crucial investment that allows deciduous plants to have the energy they need to sprout vigorously in spring.

The great “unmasking”

Only after this recycling process begins does the visual change start. Chlorophyll, the pigment that gives the green color and is vital for photosynthesis, is a molecule that degrades quickly without light. Since the tree no longer needs to photosynthesize, it stops producing it. When the dominant green disappears, something fascinating happens: other pigments that were always present in the leaf but hidden by chlorophyll are revealed. Carotenoids emerge, responsible for the spectacular yellow and orange tones we see in many trees in the Garden. In other species, cold and light stimulate the production of anthocyanins, which create the intense reds and purples.

Therefore, autumn doesn’t “paint” the leaves but rather “unpaints” the green, revealing the colors that were hidden underneath.

What happens if there’s drought?

This orderly color transition, however, requires time and optimal conditions. Yet drought —a frequent reality in our Mediterranean climate— changes everything.

If the tree has suffered stress due to lack of water, it cannot afford this slow recycling process. It switches to emergency mode and must “cut off” the connection with the leaf quickly to prevent further water loss. In this case, the leaf dries suddenly, with all its nutrients and pigments still inside, going directly from green to brown. It’s an abrupt senescence, a necrosis, that deprives us of the chromatic variety.

So, when you walk through Marimurtra and enjoy an explosion of yellows and reds, you’re not just seeing a beautiful landscape; you’re witnessing the evidence of a successfully executed natural cycle: an orderly, efficient, and ingenious retreat.

Representatives of the Marimurtra Botanical Garden have participated in the 11th Ethnobotany Conference in Catalan -held from 3 to 5 October in Alghero, Sardinia-, which is organised by the Alghero delegation of the Institute of Catalan Studies, the Botany Laboratory of the Faculty of Pharmacy and Food Sciences of the University of Barcelona and the Generalitat de Catalunya with the collaboration of other public and private institutions and entities.

The different organisations and entities taking part were able to exchange experiences, and the conference became a true meeting between science, language and culture. Marimurtra took part in a couple of the thirty-one presentations, presenting some of the methods used to disseminate information about the plant world. The central theme was ethnobotany, which is the science that studies the link between humans and plants, including their current and historical uses – medicinal, food and ornamental, among others.

In addition to the presentations, the congress included a visit by attendees to the historic center of Alghero and an excursion to the Regional Natural Park of Port Comte. This congress is held every two years with the intention of facilitating contact and the exchange of information between researchers, scholars, and enthusiasts in Catalan-speaking areas.

The presence of the Carl Faust Foundation at the second edition of the Congress of the Spanish Society of Botany (SEBOT), held last September in Seville, was a great opportunity to strengthen ties and establish new collaborations with research centers, universities and botanical gardens. This scientific meeting has highlighted the richness and diversity of current studies in botany, from conservation to new approaches in genomics and ecology.

The extensive program of the congress, of a multidisciplinary nature, has highlighted the great debates and advances that define botany today. Relevant topics such as biogeography and phylogenetic diversity, the conservation of flora and its challenges in the face of climate change, the management of invasive flora, new tools in systematics and taxonomy, as well as the contribution of citizen science and dissemination in botanical research have been discussed. There was also space for reflection on ethnobotany and biocultural knowledge, the importance of herbaria in the 21st century and new advances in aerobiology and plant genomics.

Exchange of experiences

This meeting was an opportunity to exchange experiences and discover how other gardens approach areas as diverse as collection management and outreach.

The Marimurtra Botanical Garden, through the Carl Faust Foundation, has the mission of continuing to be a first-rate botanical research center open to international cooperation. This vision, already present in the thinking of Carl Faust and shared by figures such as Pius Font i Quer, remains alive today with participation in forums where the future of botany and the conservation of biodiversity are debated.

With this assistance, the commitment to research, international cooperation and the dissemination of knowledge of the plant world is reaffirmed, thus contributing to keeping alive Faust’s legacy and his vocation of opening the garden to the world.

In Marimurtra we have a very special tree: the African Kigelia, popularly connected with the sausages tree with its spectacular fruits. It is derived from a species native to the savannas and forests of tropical Africa, believed to have originated from rivers and llacs.

A unique species

The African Kigelia is the only species of its genus, which is the most unique species. It can reach 20 meters of height and, depending on the climate, it behaves as deciduous or semi-evergreen. In Blanes, our exemplar pateix due to defoliations at any time: it has a partial rest in the winter and, in very dry and hot summers, it may also lose part of the full capacity to stagnate water.

A spectacular flowering and curious pol·linitzadors

The flowers of the African Kigelia are grouped in long inflorescences and are large, vermilion and showy. But the most surprising is its pollination system: in Africa they are pollinated above all by frugivorous rats (who feed mainly on fruit), in a phenomenon anomenat chiropterophilia. The flowers open at night, give off an intense scent and offer a lot of nectar, adaptations designed to dare these mammals.

In Marimurtra, as these ratpenats do not exist, the flowers can be visited (and pol·linitzades) by large insects such as borinots or harnesses (for example l’Agrius convolvuli) and only by opportunistic ocells trying for nectar.

Some surprising fruits

The fruits of African Kigelia are authentic giants: they can reach 1 meter long and weigh 10 kg!

In Africa, these fruits have traditionally been used in popular medicine, in the preparation of fermented beverages (since they are toxic if consumed raw). Furthermore, the whip of this tree, in being very light, has been used in craftsmanship and small canoes.

The local fauna also plays a role: elephants, giraffes, hippopotamuses, baboons, among other large mammals, feed on fruits (but they are non-toxic in nature) and contribute thereto to disperse the fires.

The story of our exemplar

Our exemplar is one of the few who believe outside Europe. The 2014 will bloom for the first time and, the next, will donate fruit: an exceptional fet that will be able to visit the Garden. From the shores, each new flowering is a small spectacle that reminds us of the uniqueness of this species and the richness of the botanical heritage of the Marimurtra Botanical Garden.

The Marimurtra Botanical Garden has enthusiastically welcomed the start of the Gardening and Allotment Workshops for senior citizens, an initiative of the Carl Faust Foundation in collaboration with the “la Caixa” Foundation and CaixaBank. This programme aims to bring nature closer to participants and offer them a rewarding experience that combines learning, health and socialisation.

The workshops, which began this September and will run until December, include a total of sixteen sessions divided into four main areas: gardening, creation of an allotment, discovery of medicinal plants and preparation of a herbarium. In the final weeks of the year, there will also be a special activity dedicated to Christmas decoration with natural elements from the Garden.

This proposal has received a warm welcome, with more than 80 people enrolled who will take part in different weekly groups. The sessions are held on Tuesday mornings, from 11 a.m. to 1 p.m., and are led by expert Anna Colomer, from deBosc. From December onwards, some activities will be held at Casal Benet Ribas, to better adapt to the needs of the season.

From the very first day, the workshops have been a great success in terms of participation, and the initial feedback from attendees has been very positive. The activity not only encourages physical exercise and creativity, but also has a strong component of cognitive stimulation and emotional well-being, contributing to the quality of life of senior citizens.

This initiative is part of the Carl Faust Foundation’s commitment to promoting scientific outreach and knowledge of Mediterranean biodiversity, while also creating spaces to share, learn and enjoy in community.