How to Make Root Cuttings of Rhododendrons

Prepare the planting pot before taking the rhododendron root cutting. Use peat moss, coarse sand or vermiculite and shredded bark in equal parts. Moisten it until it is saturated and set it aside to drain while you take the root cutting.

Insert the shovel into the soil, 20 to 30 inches to the side of the rhododendron. Dig carefully until you see the shrub's roots. Brush the soil away until you find the larger roots, about the thickness of a pencil. These are generally below the hairline roots.

Cut off a 4-inch piece of the root, using pruning shears. Immediately wrap the root cutting in a moist paper towel and place it in a plastic bag. Don't expose it to direct sun. Replace the soil around the mother plant's roots.

Pour fungicide powder into a bag and place the root inside. Seal the bag, shake it gently to coat the root and remove it from the bag.

Create a 1-inch-deep trench in the planting medium and lay the rhododendron root cutting on its side in the trench. Cover it with the planting medium.

Place the pot on a heat mat set to 70 degrees Fahrenheit.

Avoid overwatering the planting medium while the rhododendron roots. If the top of the medium begins to dry, use water from a misting bottle or drip water onto the surface to slightly moisten it.