The upper part of a grafted plant (the variety desired for fruit or ornamental traits), attached to a rootstock's root system.
In plain terms
In grafting, the scion is the variety you want (e.g., a favorite apple variety), grafted onto a rootstock (root system and vigor/disease traits). The scion provides the fruit/ornamental characteristics; the rootstock provides the root system and structural traits. Scion success depends on rootstock compatibility.
Why this matters
Understanding scion and rootstock relationship explains why grafted plants work and why compatibility matters.
In practice
Examples
Favorite apple variety (scion) grafted onto dwarfing rootstock; compact tree producing excellent fruit.
Same variety (scion) on vigorous rootstock; large, productive tree.
Incompatible grafting; scion and rootstock don't grow together properly; poor results.
High-quality fruit variety (scion) on disease-resistant rootstock; best of both worlds.
Practical applications
Choose scion (variety) for desired fruit/appearance.
Match scion to rootstock for vigor and traits you want.
Most commercial fruit trees are grafted; check rootstock when purchasing.
Grafting knowledge helps select appropriate trees for your space and conditions.
Research scion-rootstock compatibility before purchasing grafted plants.