Trees, potatoes, carrots... This study ends the near 150-year-old debate on the location and essence of the stem cells responsible for radial growth. Botany textbooks around the world will need to update their descriptions of how the two types of vascular tissues in plants form, differentiate and grow. Researchers identified key regulatory networks controlling how plants grow ‘outwards’. This could help us to grow trees to be more efficient carbon sinks and increase vegetable crop yields.