Notes From Nelson

This time of year gardeners start getting excited about gardening, but realize it's a bit early to get out and dig in the dirt. Indoor gardening and working with houseplants are options for the restless gardener. Here are some tips on propagating houseplants that I am sure will be of interest to some readers.

Most people simply place cuttings in water and hope for the best. While the shoots of species such as the lipstick plant or creeping Charlie will root in water, many species won't. Even when a shoot roots in water, they must be repotted into soil quite soon or they won't thrive.

There are several ways to propagate houseplants, and each houseplant responds best to a certain treatment.

“Herbaceous stem cuttings” are made by clipping a 4 to 5 inch piece of stem from the parent plant, with leaves attached. Make the lower cut just below a node, or the point of attachment of a leaf. Remove any leaves on the bottom 1.5 to 2 inches of the stem. Dip the base of the stem in water and then into a commercial rooting hormone, which is usually a dry powder. Shake the excess hormone from the stem. With a pencil, pen, or small stick, make a hole in your potting media, and place the stem into the hole. This allows the rooting hormone to remain undisturbed on the stem. Firm the media and moisten it. Place your cutting in a warm place. If you are taking cuttings from plants with sticky sap, allow the base to dry for a few hours prior to dipping in the hormone to reduce infection.

“Leaf cuttings” use healthy leaves from the mother plant. For some plants, you can simply stick the stalk of the leaf, its “petiole”, into the potting media. New roots and shoots will form from the base of the petiole. For other plants, such as Bryophyllum, jade plant and begonia, you need to lay leaf blades flat on the media, with their lower surface pressed gently into the media for good contact. New roots and shoots will form from the leaf, which eventually will decay.

Using just a leaf of some plants will produce only roots and no shoots. In this case, a “leaf-bud cutting” is in order. Take a leaf plus its nearest bud and a portion of the stem. Dip the stem portion into rooting hormone, make a hole in the media with a pencil, and stick the cutting into the hole.

Sword-shaped leaves on plants such as Sansevieria can be cut into cross-sections, each of which is then placed in the rooting media. New shoots and roots will form from the bottom, or basal end of each cutting.

When you propagate houseplants, you should not use garden soil unless it has been sterilized. There are microorganisms in garden soil that could damage your houseplants or reduce the possibility of successful rooting. Use a mixture of sand and peat or sand and vermiculite for root cuttings, or a good potting soil blend. Do not add fertilizer to the rooting media.

Whatever container you use for root cuttings, be sure it is clean, particularly if you have used that container before. Wash it in soapy water, rinse in clear water, disinfect in a 10 percent bleach solution, rinse again and dry prior to use. After placing the cutting in the media, firm and moisten it around the base of the cutting and cover the container with plastic to maintain a high relative humidity. A plastic sandwich bag works well placed over your container. Leave the bag loose at its base to allow for some air flow.

Some houseplant species become overcrowded in containers. Simply dividing the crowns into several segments provides plenty of planting material to fill empty pots. Be sure the soil is moist when you divide the clumps to help it remain intact against the root surfaces. Remove the root ball from the container and gently tease apart individual plantlets.