The boxwood, a popular evergreen shrub from the Buxus genus, is highly valued for its dense, fine-textured foliage and its ability to be shaped into formal hedges and topiary. Propagating new boxwood plants is the most common and easiest method for multiplying this shrub, especially for gardeners looking to create extensive plantings without significant expense. The standard technique is through stem cuttings, which produces genetically identical copies of the parent plant, ensuring the new plants share the same desirable characteristics.
The Best Time and Essential Materials for Propagation
The ideal window for propagating boxwood is during the late summer or early fall, typically from July through October. This timing ensures the cuttings are taken at the semi-hardwood stage. This means the current season’s growth has matured but is not yet fully woody and dormant, yielding the highest success rates for root development.
To prepare for propagation, you will need several specific items. The rooting medium should be sterile, low in fertility, and highly well-drained; a mixture of equal parts peat moss, perlite, and clean sand is a common recommendation. You will also need clean, sharp tools, such as sterile bypass pruners or a sharp knife, to make precise cuts that do not crush the stem tissues.
Rooting hormone is a highly beneficial material, as it significantly increases the speed and rate of root formation, although boxwood can root without it. For woody plants like boxwood, a medium to high-strength rooting hormone, available in powder or liquid form, is recommended. Finally, you will need containers with drainage holes, such as plastic flats or small pots, to hold the prepared rooting medium and the cuttings.
Step-by-Step Guide to Taking and Planting Cuttings
Selecting the correct material from the parent plant is the first action for successful propagation. Look for healthy, vigorous, and disease-free stems from the current season’s growth, avoiding any older, fully woody branches or weak, spindly new shoots. Each cutting should be approximately four to six inches in length and taken early in the morning when the stems are fully hydrated.
Once the stem is removed from the parent plant, you must prepare the base promptly to prevent the tissue from drying out. Use your fingers or a sharp tool to strip the foliage from the lower half of the cutting, leaving only three or four leaves near the tip. Removing these lower leaves reduces the surface area for water loss and exposes the nodes, the points where roots will emerge.
To further stimulate root growth, lightly score or scrape the outer bark on one side of the exposed stem base with a knife. Dip the prepared base into the rooting hormone, coating the lower inch of the stem, and tap off any excess material. Use a pencil or dowel to create a small hole in the pre-moistened rooting medium to prevent the hormone from being scraped off. Insert the treated end of the cutting about two inches deep and gently firm the medium around the stem base to ensure full contact.
Caring for New Cuttings Until Establishment
After planting, the focus shifts to maintaining a consistently humid and moist environment to encourage root initiation. Creating a mini-greenhouse effect by covering the containers with a clear plastic dome or bag helps reduce water loss, which is a major cause of cutting failure. Place the cuttings in a location that receives bright, indirect sunlight or partial shade, as intense sun can quickly overheat the covering and damage the foliage.
The rooting medium must be kept evenly moist but never saturated or soggy, which would lead to fungal growth and stem rot. Periodically open the covering to allow for fresh air exchange and mitigate the risk of disease. Root development often begins within six to ten weeks, though the process can take up to three months. Check for successful rooting by giving the cutting a very gentle tug; resistance indicates that roots have begun to form. Once rooted, gradually introduce the new plants to lower humidity and more light in a process called “hardening off” before transplanting them the following spring.