1. Layering
Definition: a propagation method by which stems are rooted while still attached to the parent plant
Uses
propagation of “trailing” species (e.g., blackberries, raspberries)
difficult-to-root species (e.g., filberts, Muscadine grapes, apple, and pear rootstocks)
producing larger-sized plant specimens in a short time period (dieffenbachia, crotons)

2. Layering - advantages and disadvantages
Advantages: simple, but highly effective rooting methods, requiring little equipment/facilities
Disadvantages: slow, labor-intensive, cumbersome methods
Current trends are away from layering in favor of other methods, esp. micropropagation

3. procedure - part of the stem is buried with the shoot tip out
Simple layering
procedure - part of the stem is buried with the shoot tip out
features:
usu. done in early spring, with dormant, 1-year-old shoots easily bent
usu. rooted by fall
useful for certain shrubs, filberts

4. How simple layering works
nutrition
stem continues to supply water/nutrients
disrupted phloem (bending, girdling, incision) causes carbohydrate, auxin accumulation at the bend
stress avoidance
because propagule remains attached during rooting
no nutrient leaching (as with mist)
light exclusion
stem sensitivity to auxin, reduced lignin production (etiolation, blanching effect)

5. Serpentine layering
similar to simple layering - a branch is alternately covered/exposed
useful for Muscadine grapes, Wisteria, Clematis

6. Air layering
aka pot layerage, circumposition, marcottage, gootee
aerial portion of a stem is girdled or wounded, with moist sphagnum moss (or other medium) used for light exclusion
useful for tropical, subtropical trees/shrubs, including litchi, Ficus,croton, philodendron, etc.

9. Mound (stool) layering
plants are cut back to “stubs” before new growth starts in the spring
hilling starts when shoots are 3-5 in. long
rooted stoolshoots are removed at the end of the growing season, then planted or stored
mother plant “stubs” are left exposed till the following spring

12. Trench layering
establishment of the mother bed: 1-year-old trees are planted at a 30˚-45˚ angle
the following season, trees are laid flat in a trench, staked down and covered (just barely) with soil
as buds break and grow out, soil is added, leaving shoot tips exposed
6-8 in. rooted layers (e.g., ‘Paradox’ walnuts) can be harvested at the end of the growing season

14. Plant modifications (natural layering)
tip layering
runners and stolons
offsets
suckers
crown division