Mycorrhizae fungi coexist with plant root systems in a sharing relationship underground

The fungi give the plant water and soil nutrients in exchange for the sugars that plants make by photosynthesis

Fungi grow much faster than roots, so they can increase a transplanted plant's effective root area many times over in only a few weeks, during which time the roots themselves have barely grown.

What Does Rootgrow Claim to Do?

Before you touch your planting area, its naturally present soil fungi are living there at the capacity of that space.
When you dig, the soil life is easily disturbed and destroyed for a time.

If you plant without Rootgrow, those disturbed native fungi will eventually recover and colonise your new plant's roots, but this leaves them vulnerable for a year or two.

Putting Rootgrow granules onto the roots makes them the centre of fungal activity from day one, giving your plants the best possible start.

Rootgrow's mycorrhizal fungi rapidly enhance a plant's root system so it:

• Finds more nutrients and water
• Needs less fertiliser
• Establishes more quickly and is less likely to fail
• Has increased tolerance to drought and difficult soil conditions

This can allow trees to grow much faster, with a higher transplant success rate.

Because mycorrhizae are alive and reproduce, one application will support a plant for its entire lifetime.

Birch tree growing with and without Rootgrow

How to Apply Rootgrow

Read about applying Rootgrow and preparing the gel.

Rootgrow is not a fertiliser, but don't add fertiliser at planting time

Rootgrow contains spores of fungi. Fertilisers, whether organic like Bonemeal, or inorganic like Growmore, can stifle the fungi.

Digging in well rotted organic matter is still important, as is mulching the surface each year.

Rootgrow and the Royal Horticultural Society

Rootgrow is the only plant / soil treatment ever to have been licensed by the RHS.

Rather than having specific studies, the RHS trialled it over 10 years of testing it on a wide range of trees, hedging, roses, and fruiting plants.

It is totally safe, natural, and organic.

RHS gardeners found that plants grown with Rootgrow:

• Had superior establishment with better natural vigour
• Overcame replant problems more successfully
• Had better developed root systems
• Were better able to cope with conditions of drought
• Had much lower levels of transplant failure, under 1% in large scale hedge planting

Specific Benefits for Roses

Rootgrow is recommended by commercial rose growers & large public garden managers

• Rootgrow helps to prevent "replant sickness" problems, potentially eliminating the need to replace topsoil in areas where roses had been grown before.
• Rootgrow is effective at extracting Phosphorous from clay soils, which enables roses to flower earlier and better throughout the growing season.

"At Rozenhof Lottum, one of the five national rose gardens for the certification of “Toprozen” in
the Netherlands, a mycorrhiza root dip was used when planting new rose cultivars in test
compartments in early May 2007, actually too late for planting bare-root roses.
In one compartment mycorrhiza was left out.
The roses of all mycorrhiza treated compartments survived and developed reasonably, while the roses in the untreated compartment died of and were removed in August"

"The well-known garden architect Ineke Greve, Huys de Dohm, Heerlen, had a rose replant
problem in 2005/2006 when creating new borders in the “Long Garden” of her estate.
In autumn 2006 she decided to repeat the planting with new roses without changing soil but using
mycorrhiza.
In June 2007 when her gardens were open for visitors, the young roses looked healthy
with many buds and flowers and the lady was very content with the result and started to promote
the product"

Specific benefits for trees and specimen plants

Many larger trees and specimen plants can struggle to make good growth in the early years after planting.
This is usually due to inadequate water being available after planting. A contributory factor is that the roots of a bareroot tree take time to establish.
So, immediately after planting, the roots are catching up with the amount of top growth they have to support.

If Rootgrow is used, the colonised roots will have access to a greater volume of soil (and therefore water and nutrient) much faster than normal, and this helps to balance out the root to shoot ratio.

Recommended by UK Highways Agency for Urban Planting

Specific benefits for evergreen hedging

Popular evergreen hedges like Box, Yew, and Holly are slow to establish, and have higher failure rates than deciduous plants because they are in growth almost all year. They benefit the most from the support that Rootgrow provides.

OK, That's All Very Well, But Are There Alternatives?

Mycorrhizal fungi are "everywhere", and they are most abundant in woods & forests:

• Go to your nearest wooded area with deep leaf litter
• Scrape off the top layer until you reach well rotted leaves mixed with some soil
• This should be rich in mycorrhizal spores
• Chuck it in the planting hole, use plenty as mulch if you can, and hope for the best!

Further Reading

Robert Pavlis has a great series of articles investigating the claims of Mycorrhizal products in North America, at least some of which appear to be a complete waste of money!
Others seem like they probably do help, but scientific studies are lacking.

• Mycorrhizal Inoculant Investigation – Do They Work?
• The Mycorrhizal Fungi Myth
• Mycorrhizal Fungi – The Latest Scientific News

Rootgrow, however, has been trialled by the RHS, and several other studies that show its efficacy on woody plants (like we sell), but not really for annual crops like wheat:

• Effect of arbuscular mycorrhizal fungi on yield of different trees and shrubs
  This 2001 study by Plant Works, the company that makes Rootgrow, delightfully found that, in addition to greatly increasing growth rates and almost preventing tree failure, Rootgrow made the plants significantly "booshier", which is how one knows they are so big and booshy.
• Use of Arbuscular Mycorrhizal Fungi to Improve Strawberry Production in Coir Substrate
  This 2016 study found that Rootgrow increased yield and the number of Class I fruits, particularly under stress conditions of water or nitrogen deficiency.
  Note that coir is a soil-free growing medium, in which the fungi struggled to colonise the strawberry roots.
• Experimental evaluation of biological regeneration of arable soil: The effects of grass-clover leys and arbuscular mycorrhizal inoculants on wheat growth, yield, and shoot pathology
  This 2022 Study found that Rootgrow had no impact on wheat (which is an annual, not a woody or perennial plant), and in some cases reduced yields. Leaving fields fallow for three years with cover crops of clover and grass gave the best results.
• Mammoth Round Up of Scientific Studies & Unofficial Trials
  Only one of the studies is about Rootgrow specifically (see page 289), tested on Common Alder, showing a:
  • 16% lower mortality rate
  • Significant increase in root collar diameter leaf biomass.