We have been using Biochar for a while , we use it everytime we plant as well as mycorrhizal fungi for healthier roots.

Biochar is ideal for transplanting all types of trees, shrubs and woody plants- Used for faster establishment and root growth- Essential for improving plant vitality and reducing losses. It defends against transplant shock and drought stress.
Use Biochar when planting bare‐root trees and shrubs, or to protect established trees.
Adding enriched biochar compost to your plants will increase nutrients and expand microbial populations.
Biochar improves soil health, nutrition and structure and reduces the need for watering.

For healthier plant we only use organic treatment, better for nature but mostly because they work so well..
Biochar – a one off, permanent soil amendment
Mycorrhizal fungi maximises nutrients & water uptake.
Seaweed for essential minerals and trace elements.