Every plant has its pollinators. You may see wings flapping around the lilac flower of the buddleja plant, a Himalayan species typical of English gardens that attracts a large number of insects. But many are “weeds”. They thrive in the forgotten corners of our lives. They conceal passageways and revive garden walls: clover, mallow, plantain –they not only give nectar, but they are “nurturing plants” on which butterflies can lay their eggs.
"In our culture, weeds denote neglect, safe harbor for pests and safety risks," explained Simona Bonelli, a professor in the Department of Life Sciences and Systems Biology at the University of Turin and head of the Progireg project that analyses the harnessing of nature for urban regeneration."
"In urban areas and sometimes in fields, we use herbicides to fight weeds that infest farm crops. But by damaging unwanted plants, we also harm insects and, ultimately, we do harm to ourselves. Conversely, where we let them grow in a somewhat disorderly manner, there we find vibrant, colorful, and multifaceted life."
Uncultivated flower beds are a feast for bees and butterflies. And thus, the famous old world swallowtail alights on wild fennel stalks, and the two-tailed pasha lands on its favorite plant, the strawberry tree.
Designing a living city involves embracing a perspective that differs from the traditional approach to gardens. It means shifting from “conventional” decorative plants, with their established parameters of beauty, to “functional” ones.
"We often choose plants such as ornamental Prunus and Lagerstroemia with “double” flowers, which produce neither nectar nor pollen, unlike varieties with simple flowers," explained Monica Vercelli, an expert researcher of honey bees and other apoids and flora useful to pollinating insects.
"Urban (aesthetic) decor is one thing, but nature deserves a respect of its own. Gradually, however, we are beginning to understand that green areas are theaters of a system." A “trophic” system, i.e. a balanced food chain that encompasses all living organisms. Walking through nurseries, we see that they too are changing and offering more native plants with flowers that appeal to a different sense of “discrete” aesthetics.
"To have gardens and balconies populated by butterflies and bees, we can plant lavender and other aromatic plants that pollinators crave, such as thyme, oregano, and rosemary," explained Simona Bonelli. "Asteraceae such as daisies, Bellis perennis (daisies), Centaurea such as cornflowers and thistles, and Umbelliferae such as wild fennel." But that's not all. "We sow species in the same pot with flowers of various shapes and colors that strengthen each other and, together, attract various pollinators during the entire flowering season," adds Vercelli. "We can combine the hellebore that blooms in winter with meadow sage, which blooms in spring and autumn."
Cities are still barriers of separation, and the most common butterflies are found there: in Italy, old world swallowtails, cabbage butterflies and moths. The same applies to bees: honey bees and bumblebees are most common. "Everyone can contribute with their balcony," said Bonelli. "The important thing is to create communicating green areas that act as ecological corridors, not islands of flowers that are difficult to reach because they are not within easy reach."
In the mountains, then, "we often see houses covered with a particular type of geranium, pelargonium, which comes from South Africa," explained Bonelli. "And from there, they carry licenids, tiny butterflies that destroy the flowers and infest what they find. We have examined the cases of two alpine parks in difficulty, and we proposed a change with surfinias."
The trick is to diversify. Don't trivialize and think local. And we must care for the little Edens we create, with a sense of responsibility. We sow shrubby medicinal species, such as strawberry trees along the coasts of Liguria, Sicily, and Sardinia. We also sow hawthorn, dog rose, blackberries, raspberries, and lemongrass in gardens located in colder areas. We must just remember to consult the local plant atlases. For sure, they will attract a few little animals.