The petiole is the stalk between a leaf blade and the stem. On cannabis, each palmate leaf sits on one petiole that joins the stem at a node; the leaflets fan out from its far end. The petiole contains vascular bundles (xylem and phloem) that carry water in and sugars out.
In practice
Petioles feature in two everyday jobs. In diagnosis, colour and stiffness matter: red or purple petioles are common and often genetic or cold-related, and only mean much when combined with other symptoms such as dark, dull leaves (possible phosphorus issues) or poor growth. Drooping, soft petioles with turgid-looking leaves point to watering or root issues.
In leaf management, growers who remove leaves cut the petiole a few millimetres from the stem rather than tearing it, which avoids ripping the stem skin and the bud site in the axil. The GenetixBay approach is "tuck, don't pluck": tuck a fan leaf under a neighbouring branch by its petiole rather than remove it, where possible.
Don't confuse with
- Node: the point on the stem where the petiole attaches.
- Stem (branch): carries nodes and buds; a petiole carries only a leaf.
- Midrib: the central vein inside a leaflet.
