I’m planning to propagate some boxwood cuttings this year but have many questions before I get started.
1. Is it possible to do the entire operation outdoors? I have no greenhouse, and limited space inside.
2. Is it possible (and advisable?) to root and plant out the cuttings all within the same year? I’m picturing taking the cuttings in mid summer, establishing roots, then planting out in early autumn. Does that timing make sense?
3. If the above are not possible, then can I use my indoor LED grow light setup (usually used for seedlings) to overwinter the cuttings?
Please let me know if there are any other considerations I may have missed.
You can propagate your cuttings outdoors, and the best time to do so is in the late summer or early fall, and the little plants will be ready to plant outdoors the next spring. They would likely be too tender to survive the GTA winter, if you planted them outside this fall.
The best time to take cuttings is in the middle of summer, after mature leaves have appeared, and flowers have faded. Take cuttings of sturdy, healthy sprigs about 10-15 cm (4-6 inches) long from mature boxwoods, and strip off the leaves on the bottom half of the cutting – this exposes the growth nodes, from which roots will emerge. The cuttings should have leaves only, not spent flowers or buds.
If you wish, dip about 1 cm (½ inch) at the bottom of the cutting in rooting hormone powder [although this is not necessary]. Bury each stem to around a third of its length in a small pot (that has drainage holes) filled with well-draining potting medium; it’s recommended not to use potting soil at this stage, as it contains lots of nutrients and could promote rot. You can purchase a potting medium or make your own. A common soil-less mixture consists of equal parts of peat moss, perlite (and/or vermiculite) and clean coarse sand. Coconut coir can take the place of peat moss (which is a non-renewable resource) and bark could be used instead of sand. There are likely many formulations published online for “make your own” rooting media.
Some experts recommend making a tent of clear plastic to place over the pots. This will hold the moisture in and create a mini-greenhouse. Place sticks or pencils around the edge of the little pots and drape the plastic over top, leaving the bottom loose. Put the pots in a warm location that gets lots of indirect sunlight, but not deep shade.
If you use a plastic covering, open it at least twice a week to ensure the cuttings get fresh air and to check on the soil. In any event, check the pots a few times a week – don’t let the soil get too wet or too soggy. After 4-8 weeks, roots will start at each of the leaf nodes that have been buried in the dirt. To see if roots have formed, tug gently on the stems. If they are well-rooted, you’ll feel resistance – and they will be ready to transplant into a larger pot with potting soil, if you wish. Overwinter the pots in a cool, bright location (e.g., a sunny window), ensuring they don’t dry out. Alternatively, you could use your grow lights!
There are also helpful videos on YouTube that provide practical demonstrations of how to propagate boxwoods.
May 30 2021