Hardwood cuttings are those made of dormant wood. There are two types of hardwood cuttings: either deciduous species, or narrow-leaved evergreens. Deciduous species often propagated from hardwood cuttings include privet, forsythia, honeysuckle, willow, grape, plums and rose understocks,.
Use of hardwood cuttings is the most common way to propagate narrow- leaved evergreens like yew, juniper, arborvitae, and Chamaecyparis.
Rooted privet cuttings
Deciduous hardwood cutting propagation is a low cost method that uses dormant cuttings from last season's growth. They are typically 4 to 30 inches in size and usually inserted deeply in the medium. Many ornamental shrubs propagate easily and require no auxin treatment.
They can be handled in several different ways. They may be directly planted in the field in the fall, they may be rooted in the greenhouse, or they can be callused under refrigerated storage prior to planting in the spring.
Plum cuttings machine planted in the field.
Some propagators find that the timing is better if they collect dormant cuttings in the fall and store them in a cooler just above freezing for the winter. These cuttings are usually packed in boxes that retain moisture and stored with base of the cutting up for good aeration.
During cold storage, these cuttings callus (arrow) and are ready to be rooted in the field or under greenhouse conditions in the spring.
Callused cuttings collected and stored in the cooler since fall or very easy to root cuttings like privet or forsythia cuttings taken in the early spring can be rooted in the greenhouse.
Small quantities can be rooted in flats or they can be planted in greenhouse ground beds and handled in a similar fashion to field planted cuttings.
The most common way to root narrow-leaved evergreens is by dormant hardwood cuttings. These are taken from December to February and stuck in a porous medium (like sand) and usually rooted in minimally heated greenhouse structures.
Mist is not required because cuttings are dormant, but they should not dry out. Auxin treatment is not required but usually improves rooting as does bottom heat.
Narrow-leaved hardwood cuttings need a well-drained medium to root well. This is one place where coarse sand is still used as rooting medium.
Because these cuttings have reduced foliage compared to softwood cuttings, they can be placed closely together in the propagation bed.
This type of cutting may also benefit from taking heel cuttings.