Layering Definition a propagation method by which stems

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)

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

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

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)

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

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.

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

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

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