Comments Off on A Boxwood Lover’s Guide to Propagation
“Buxus-microphylla-sinica” by Sten Porse – Own work. Licensed under CC BY-SA 3.0
The most popular plant among professional landscapers is boxwood (Buxus spp.), according to a poll of Lawn and Landscape magazine’s readers. Thus the versatile evergreen has been dubbed America’s most popular shrub.
Although there are about 150 cultivars and species available in nurseries, the most commonly grown is the common or American boxwood (Buxus sempervirens), and its cultivar, ‘Suffruticosa,’ also known as English boxwood. Both are hardy to USDA zones 5 through 8, and propagation of the two is identical. The principal method of boxwood propagation is cuttings.
The best time to take a boxwood cutting is in July, but you will also find moderate success with cuttings taken after that, until December. The ideal time of day to take a boxwood cutting is early in the morning. This is when the plant’s stems have the highest moisture content and will be less likely to dry out.
Gather the following items:
- Sharp pruning shears
- Coarse sand
- Planting pot
- 4 jumbo craft sticks, 9-inch long twigs or chopsticks
- Plastic, sealable bag
Always disinfect your pruning equipment before using it. The easiest way to do this is to soak the pruners for five minutes in a solution of 1 part of water and 3 parts of Lysol. Rinse them well in clean water and allow them to air dry.
You’ll find gardening advice online, at sites such as EHow and others that recommend using bleach to disinfect your pruning equipment. NEVER use bleach, unless your pruners are disposable (is there such a thing?). It is highly corrosive and a health hazard. In fact, stop taking gardening advice from sites like that. I am shocked at what I read there. I linked to it, above, just to show you how absolutely uninformed these types of sites are.
Ok, off the soapbox. It’s important that you don’t allow the cutting to dry out during the process, so prepare the rooting container before taking the boxwood cutting. The size of the container isn’t important but it is critical that it has holes in the bottom for drainage. This helps avoid rot.
Fill the container with coarse, moist sand, to about ½ inch of the rim. Insert the craft sticks, twigs or chopsticks into the sand at the rim of the pot, evenly spaced. Finally, use your finger or a pencil to create a 2-inch deep planting hole. (refs 5)
Taking the Boxwood Cutting
Choose boxwood that is disease- and pest-free from which to take the cutting. From the tip of the stem, measure back 6 inches and make the cut with the pruning shears. Remove the leaves from the bottom inch of the cutting.
Expert opinions vary on whether or not rooting hormone is beneficial when propagating boxwood cuttings. The American Boxwood Society claims that results are the same, with and without the use of rooting hormone. In his studies, noted horticulturist and professor Michael A. Dirr, Ph.D found that the use of Rootone 10 and several other hormones with boxwood caused burns and he suggests using Hormodin #3 instead.
Should you decide to use rooting hormone, pour a dime-sized portion into a small bowl, moisten the bottom inch of the cutting and roll it in the hormone powder.
Insert the cutting into the prepared container and pack the sand around the base. Carefully slip the container into the plastic bag, arranging it so that the sticks at the edge of the pot hold the plastic away from the cutting’s foliage. Seal the bag and place it in a lightly shaded indoor area where it won’t be disturbed.
Check the moisture content of the sand periodically to ensure that it doesn’t dry out. If it appears to be dry, give it only enough water so that the sand is moist, not saturated. The boxwood cutting should root within two to three months and it should be strong enough to be planted outdoors the following spring.
I highly recommend The Reference Manual of Woody Plant Propagation; Michael A. Dirr and Charles W. Heuser, Jr.