People don't normally picture guerrillas as green thumbs, but there's an underground movement taking root across the globe, involving rogue gardeners, night missions and "seed bombs". Curious to learn more, we spoke to Giacomo Salizzoni, a landscape architect and guerrilla gardener living in Florence, Italy.

In this interview, Giacomo opens up about the politics of gardening; his goal of "greening" Florence; and why people like him are breaking the law in the name of plants.

What is guerrilla gardening?

According to Wikipedia, 'guerrilla gardening' is “gardening on another person's land without permission”. It is the illicit act of “reclaiming land from perceived neglect or misuse and assigning a new purpose to it”. Often done in secrecy, guerrilla gardeners take possession of unused land to plant flower gardens or cultivate vegetables. It is considered a form of 'pro-activism' intended to provoke change from the bottom up.

It can be a political gesture, which is usually a one-shot attack with seed bombs, or it can have a genuine horticultural goal. The green "attacks" by guerrilla gardeners are meant to challenge access to urban spaces and improve the condition of land sooner than bureaucracy does.

What is a seed bomb?

Seed bombs are an easy way to distribute seeds into derelict and abandoned areas that you want to beautify with plants and flowers. The seeds are encased in a mixture of clay and compost, which protects the seeds by preventing them from drying out in the sun, getting eaten by birds, or being blown away by the wind.

Seed bombing is relatively easy. Seed bombs are scattered directly on the ground in spring and left there to grow on their own. Sufficient rain will permeate the clay, and the seeds inside will begin to sprout aided by the nutrients and soil microbes surrounding them. This method has been used in gardening for centuries, but has only taken on political significance in the twentieth century. In fact, the North American First Nations' tribes used seed bombs to sow the land.

Why are you a fan of seed bombs?

Seed bombs are a simple tool but have more power in them than just causing plants to grow! We use them in our laboratories with children who learn and play, making their hands dirty in the process. We use them for some night-actions, too, and it’s also a perfect marketing tool. We are even producing them for weddings, parties, openings and celebrations. They represent something that can slowly explode and grow into a very powerful action.

How, exactly, are they made?

For a long time, we have been making a lot of seed bombs. Recently, we have been helped by a social cooperative to produce them. It’s actually very easy, if you have the right ingredients. What you need is clay (that has to be in powder form), compost (with no smell), water and the right amount of seeds, depending on their size. Once made, we leave them to dry for a few hours and then they are ready to be thrown.

You live in Florence, and are very active in making your city green. Can you tell us more about what's happening there?

Florence is a city where the green areas have always been important for the community; from the Boboli Gardens to the Giardino Torrigiani. Urban farming then was always a trend, and today we honour that tradition. Florence has around 500 small pieces of land that can be rented directly from the City Hall. What is missing, though, is the culture of community gardening that only grows when a diverse group of people becomes involved. We think this social integration is fundamental to our project.

Unfortunately, there are not many activists in the city who focus on community gardens. So this motivated us to do it ourselves; we created the non-profit ‘Community Garden Association’ in order to solve this problem.

How do Florentines feel about their city?

They are very proud and very protective because they love it. This has two consequences: the city’s heritage is preserved, but this, in turn, can result in stagnation. The general thinking is that it’s easier to leave things as they are – since they are so beautiful – rather than taking the risk and maybe ruining it.

How do you address this inertia you mentioned earlier?

We have been doing workshops, giving classes and involving some groups of people in guerrilla gardening actions. We’ve also been working with the City Hall for "world parking day". This is about creating a small community garden in the centre of the city, and in beautifying some riverbank areas of the river Arno, with a temporary park over the summer.

We have also used the "seed cards" we’ve created as a tool to spread the word to people about greening our city. Our next step is creating the community garden at a bigger level, and as a space to cultivate, integrate, learn and teach. Once a project starts, we initially receive some criticism from the community, but, as it builds, it’s normally welcomed, and more and more people start to get involved.