Citrus species trees are subtropical by nature and produce softwood and semi-hardwood shoots that can be used for cuttings and successfully rooted to produce clone trees. They key is to harvest cuttings in their active growth phase, according to Purdue University. The harvesting and rooting process is straightforward but the post-planting care is crucial to its survival and the production of a viable root system. Citrus tree cuttings can take three to six weeks or more to produce roots, at which point they can be transplanted into a long-term growing container or ground location.
Harvest softwood or semi-hardwood shoots from the tip of your young citrus branches during a period of active growth in the spring, summer or early fall. Select branch tips with at least three sets of healthy leaves attached and roughly 4 to 6 inches in length. Make certain the tree has been watered recently and is well-hydrated.
Take the cutting immediately before you intend to pot it. It must not be allowed to dry out and should be kept in water in a cool low-light spot until planted, if need be. Place the cut on the bias just 1/4 inch below a leaf node. Remove the leaves on the lower 2/3 of the cutting.
Prepare a nursery pot with drainage holes, filling it 3/4 of the way up with soil-less potting mix designed for seedlings. This will be loose enough to allow tiny roots to easily form but still keep the cutting upright. Soak the soil thoroughly and let the excess water drain away. Create a narrow hole in the center of the soil with a pencil.
Dip the bottom inch of the cutting into tepid water and then rooting hormone powder to coat it. Slide 1/3 of the cutting into the hole and firm the soil around the cutting to secure it upright.
Slide two dowels into the soil on either side of the pot and tent over them with a clean, clear plastic bag to create a mini-greenhouse. Place the tented pot in a location with bright but only indirect light, where ambient temperatures can be controlled to remain between roughly 70 and 75 degrees Fahrenheit; warmer is better for citrus.
Water the cutting and soil as needed to keep the soil-less mix evenly moist but not sopping wet. Let the waste water that collects the the bottom of the bag drain away.
Check for root formation after three to six weeks, though it may take longer. Transition the plant slowly from its tent after healthy roots have formed. Open the bag slightly over several days until it is uncovered completely within two weeks. Keep the soil moist.