A guide to indoor trees

Hi, I'm Sam. I've been dealing with trees for all my working life. I started off as a landscape gardener, so I used to work with outdoor trees. Now I'm the Head of Major Projects at Plant Plan, I spend my time designing stunning trees into workplaces across the country.

I recently recorded a podcast with Carlsson talking through trees but thought I'd create a written version, too.

If you’ve ever seen an indoor tree, the chances are it came from the Netherlands. The Dutch are the dominant force in the industry, with vast nurseries supplying businesses and homes across Europe. But they aren’t the only ones growing indoor trees.

In Europe, Spain and Italy (particularly Sicily) are major producers, boasting enormous nurseries that supply mature trees for interior and exterior projects. Further afield, China also has significant tree-growing operations, while Florida was once a key player before weather conditions made large-scale production more challenging.

When trees are imported from China, the process is surprisingly complex. The trees must be stripped of their foliage before being shipped in containers for 12 weeks. Once they arrive in Europe, they need time to recover before they can be installed in their final locations.

The definition of a “mature” tree varies depending on who you ask. In the industry, a tree over three metres tall with a trunk diameter of 200–400mm is considered mature. However, for many clients, the benchmark is even higher: four to five metres in height, with a substantial trunk that makes a bold statement in an interior space.

This distinction is important when specifying trees for a project. Large trees require careful planning, from logistics to structural considerations, which can dramatically affect the feasibility of an installation.

Ficus trees (part of the fig tree family), such as Ficus microcarpa 'Nitida', are the go-to choice for indoor spaces. They’re hardy, adaptable, and aesthetically pleasing. However, one species that’s gaining popularity is the Bucida tree, also known as the black olive or shady lady.

Bucida trees under four metres tend to be sparse and spindly, offering an open, delicate canopy. But once they reach four or five metres, they develop a beautifully structured trunk and a dense, dissected canopy that mirrors the appearance of an outdoor tree.

1. Light

Light is the single most important factor in keeping indoor trees alive. No tree will survive in a dark space without proper lighting. Fortunately, modern solutions exist: auxiliary lighting can provide the full spectrum of light required for growth. Unlike standard LED lights, plant-friendly lighting includes the necessary red, blue, and green wavelengths to support photosynthesis.

2. Water

Trees can be surprisingly thirsty. In one project I worked on, a single tree required 80 litres of water per week! For buildings with strict water consumption targets, this can pose a challenge.

Some installations include irrigation systems, but many retrofit projects rely on manual watering with cans. Watering frequency varies with the seasons, for example, trees need more in summer and less in winter.

3. Cleaning

Just like on other indoor surfaces, dust and dirt can accumulate on their leaves, blocking light absorption and reducing their ability to photosynthesise. This not only impacts their growth but also diminishes their ability to filter air and produce oxygen.

Regular cleaning (we recommend at least once a month) helps trees thrive. Wiping leaves with a damp cloth or giving them a gentle shower can remove dust and keep their foliage looking vibrant. In commercial spaces, professional plant maintenance teams like ours often use misting and leaf-cleaning solutions, particularly as tall trees are hard to reach!

Indoor trees will live for as long as they are maintained properly. This is one of the wonderful things I love about putting beautiful trees in spaces, if it's properly looked after, it will probably survive me!

It also means trees are fantastic investments, they're a one-time purchase that will bring beauty and joy for decades to come.

If an indoor tree is struggling, you're going to notice excessive leaf drop, discolouration of foliage, and bald patches in the canopy.

These symptoms can be caused by a lack of light, improper watering, or environmental stress. The faster you can spot these issues and get experts like us involved, the better your chances of restoring the tree's health and preventing long-term damage.

Indoor trees can survive under artificial light only, but only if it provides the right spectrum and intensity. Standard LED lights are not sufficient, as they lack the full spectrum required for healthy growth. As I mentioned above, high-quality horticultural lighting that includes peaks in red, blue, and green wavelengths can effectively support photosynthesis and plant health.

1. Weight considerations

A five-metre tree can weigh half a tonne. Once you factor in soil and substrate, the total weight can exceed 1,500kg. This means structural loading must be carefully assessed early in the design process.

2. Getting trees into buildings

Sometimes, trees simply come through the front door on a pallet. Other times, installations require major road closures, cranes, or even spider cranes inside buildings.

One of our most challenging projects involved craning a tree up the side of a building, over a balustrade onto a terrace, and then lowering it down a custom-built scaffold slide to the floor below.

3. What if a tree fails?

If an indoor tree fails, it's pretty easy to get rid of it, you simply chop it up! But the real challenge is getting a replacement in, especially if it involves complex logistics. One project I worked on had dozens of trees, so a mobile crane was kept on-site permanently in case replacements were needed - that's what I call forward thinking!

When it comes to my favourite trees, there are many contenders! Outdoors, the Prunus serrula (Tibetan cherry) stands out for its deep red, peeling bark and stunning blossoms. For indoor projects, Bucida trees are a favourite for their striking structure and character. I also love an ancient Oak.

One of the most memorable projects involved a tree that had to be stored for six weeks before installation because Transport for London kept delaying the road closure we needed to crane it in! It was kept alive with artificial lighting and a controlled watering system, a pretty intense process that caused us plenty of sleepless nights! But the effort paid off and the tree is now thriving in its new home and will be there for decades to come.