If you watch Beechgrove Garden then you’ll have seen that recently I decided to remove the knackered arch from the herb garden and instead of replacing it with another similar arch I went for some soft landscaping via two fastigiate yews (Taxus baccata).
When planting this, the usual rules applied. Make a hole twice the width of the root ball but the same depth.
Pop in the rootball of the plant then put in a stake at 45 degrees to the tree towards prevailing winds whilst avoiding piercing the root ball and tie it in.
Back fill with a mix of existing soil and some fresh compost or topsoil to ameliorate the mix. Consolidate and firm in well. Water thoroughly.
So far, so standard. It is the magical sprinkle of white powder that was placed in before planting that is of real interest though, I am of course talking about mycorrhizal fungi.
What is mycorrhizal fungi?
At present, it is believed that over 90% of plant species create mycorrhizal fungi associations.
Myco (fungi) rhiza (root) refers to the specific fungal species that creates a unique, symbiotic bond with roots of plants.
Ultimately I like to think of it as a rock star and their manager. In this case, the yew is the rock star and the mycorrhizal fungi is the manager.
The yew is the main event that everyone sees and knows. The star that can be seen and adored. The mycorrhizal fungi is the manager.
It works behind the scenes unknown to the masses and unseen by many. Under the surface it creates a bond with the roots of the rockstar yew.
It sets up basecamp here so it has a guaranteed source of water, sugar and starches in order to grow.
In exchange for these guaranteed nutrients to live and thrive it returns the favour by spreading way out in the soil rhizosphere with its hyphae (strands) which extend hundreds of times further out than the rock star yews could.
In turn they garner the nutrients and water from hard-to-reach places that are likely untapped by other plants and which is otherwise unavailable to the yew.
Endomycorrhizal
This magical fungi actually comes in two discernible forms, endomycorrhizal and ectomycorrhizal.
Sounds confusing but as always, buckle up and pay attention! It isn’t as nerdy as it sounds.
Endomycorrhizal fungi are widely present in plant roots and work by penetrating into the cortical cells of the plant roots. Here they create something called arbuscules.
These attain the xylem and phloem which essentially provide water as well as sugar and starches.
Ectomycorrhizal
Similar yet different are Ectomycorrhiza. Ecto is the Greek for outside. These fungi work by also penetrating the root and forming a special sheath. This is known as a Hartig net.
This a special network of latticework like hyphae that spread between epidermal and cortical cells (i.e. outside and inside cells).
Both Endo and ectomycorrhizal fungi are very important in the health and development of the plant that is lucky enough to have it form around its roots.
Living testament
I am in fact a witness to the marvels of mycorrhizal fungi. At Pitmedden Garden I was tasked with replacing the historically important box hedge in the lower garden parterre.
Having trailed some replacement in the herb garden I was satisfied with the success of the English yew (Taxus baccata) and the box honeysuckle (Lonicera pileata ‘Maigrun’).
As someone with the weight of the world on my shoulders having to replace the absolutely immensely historically important Buxus sempervirens at Pitmedden with something else, I wanted to make sure I succeeded.
To ensure success I bought English yew from a reputable nursery and planted it bare root during the winter (end of February).
Before planting into the newly-dug and ameliorated trenches I used rootgrow professional mycorrhizal fungi approved by the Royal Horticultural Society (RHS).
It came with what I can only describe as wallpaper paste mix.
Once the dry paste was mixed with water it created a gloop that you swished the bare roots around then then dipped it into the mycorrhizal fungi powder.
This ensured that the powder definitely stuck to the roots. Imagine it a bit like coating you banana into Greek yoghurt then rolling it in breadcrumbs to make a banana fritter.
A few weeks after planting in all that yew it was thankfully looking very happy and growing away nicely. Phew!
The power of the fungi will hopefully help these important new hedges to thrive for generations of future visitors!
Take care and happy gardening.
