This crucial gardening ingredient is key to bigger, stronger plants – and gives new shrubs the best possible start

Mycorrhizal fungi are one of those gardening terms that get a lot of hype, but they're still a bit of an enigma to many gardeners. What actually are mycorrhizal fungi? And what do they do?

Well, I’ve spoken about the benefits of mycorrhizal fungi when planting roses before, but the majority of plants on our planet benefit from them, too. They're crucial to a healthy garden – and according to experts, they can more or less double a plant’s root system. Mycorrhizal fungi exist naturally in the earth’s soil, but there are ways to incorporate them into the ground before planting to give new plants a boost and help them settle into your garden.

But first: what are mycorrhizal fungi? I’ve broken them down with the experts and explored the key benefits for plants, shrubs and trees.

What is mycorrhizal fungi?

In a nutshell, mycorrhizal fungi are, well, a type of fungus, and they're a really important companion to plants. They're normally used when you’re planting a new shrub or tree to aid establishment – Empathy Rootgrow Mycorrhizal Fungi (available at Amazon), for example, is sprinkled into the planting hole before your plant enters the ground.

‘Mycorrhizal fungi live in a symbiotic relationship with plants, providing them with essential nutrients and aiding in their growth,’ says Envii. ‘In fact, 90% of all plant life depends on mycorrhizal fungi!

‘Mycorrhizal is the adjective used to describe the network of fungal filaments that mycorrhiza create with the soil. These microscopic threads net together to form a web called mycelium.’

Apparently, those nets can stretch for hundreds and hundreds of feet, reaching far and wide for water and nutrients. Envii also told me that the nets can connect with other plants to share nutrients (very sweet!).

‘Mycorrhizal fungi work with the plant roots to almost double the root system of the plant,’ adds Dave The Plantman in conjunction with Mims Pottery.

So, why should you use mycorrhizal in the garden?

Where to buy mycorrhizal fungi

What are the benefits of mycorrhizal fungi?

We’ve already mentioned that mycorrhizal fungi aid plant growth and establishment, but how exactly does that work?

‘Mycorrhizal fungi increase nutrient intake,’ adds Envii. ‘Using a vast network of tiny thread-like structures that can extend further into the soil than a plant’s roots, the fungi increase the absorption of nutrients such as phosphorus and nitrogen. By providing the plants with these essential nutrients, they can grow bigger and stronger.’

So, as well as keeping your plants hydrated, mycorrhizal fungi will give your plants all the goodness they need to thrive.

‘They also create some resilience in the plants against diseases and toxins,’ Envii adds.

As I mentioned before, gardeners often use mycorrhizal fungi when they’re planting roses and other shrubs.

‘Mycorrhizal fungi can support root development and improve plants’ access to water and nutrients, helping them establish more successfully,’ explains Andrew Jackson, founder of New Build Manifesto.

Envii mentioned that mycorrhizal fungi exist naturally in the soil, but over time, chemicals and fertilisers can damage those systems. It's wise to use an organic mycorrhizal fungi like Envii Root Well, which is enriched with beneficial bacteria. It can be added to plants that are already in your garden, too, to improve their root system.

If you want bigger, stronger plants, don't skip mycorrhizal fungi – especially if you're adding a new shrub or tree to your garden.