Andrew Mikolajski, a writer, speaker, and RHS judge, gave an interesting and often amusing talk for Ticknall Garden Club on March 11th, 2025, on the importance of roots for vigorous plant growth. The first part of his talk focused on how plants evolved from the sea bed to surviving on land when sea levels fell, how roots developed to ensure plants had sufficient water and nutrients to grow, and how they work with the broader ecosystem.
There are various types of roots (fibrous/tap roots, etc) and not all roots are underground; some are climbing, and others are aerial. Roots have many purposes, from stabilising and anchoring plants to providing water and nutrients.
Undercutting of roots has been used by horticulturists for many years to improve plant growth. This is a process whereby deeper roots are severed, which encourages a more vigorous root system to develop and improve the quality of the trees and shrubs when replanted. It also minimises transplant shock when the plant is moved or replanted. More recently, air pots are being used by nurserymen to grow plants with more fibrous root systems, again to minimise transplant shock.
As much of a plant’s root system is underground, Andrew gave a number of useful tips on how we can take care of roots to encourage strong plant growth:
Firstly, divide hellebores in September when they are not flowering, as they are very susceptible to transplant shock. Keep the younger white roots, discard the darker older roots and replant.
Give bare-root roses a good soak before replanting. Soil will cling to the roots better, which encourages new root growth.
Furthermore, when buying plants from garden centres, break up the roots, remove as much of the compost as possible and soak before planting.
Finally, if container-grown shrubs look ‘sad’, remove and wash off the compost, trim roots by a third and replant with fresh compost.
He also suggested composting perennial weeds by keeping them in plastic bags in the shade and using liquid gold (not for those with a sensitive disposition!) to kill the weeds over time.
Andrew also recommended planting shrubs in cardboard boxes to prevent root issues, especially in rose-sick soil. His mantra seemed to be ‘if in doubt wash the roots and separate before replanting’ and if unsure, discard.
Unfortunately, some root problems cannot be overcome. Honey fungus can’t be treated, and if present, it is best to dig up any plants, remove the soil, line the area and replant with perennials.
It was an enjoyable evening, with his reference to ‘liquid gold’ evoking lots of comments and chuckles from the audience.
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