I always enjoy growing my own plants, but there’s something even more exciting and gratifying about propagating them - producing plants by dividing, grafting, or taking the cuttings from existent stems. It’s an interesting and very easy-to-follow process.
One of the easiest plants to propagate is the begonia. I have been collecting begonias for many years. The genus begonia contains about 1500 different plant species and hundreds of hybrids. Rhizomatous begonias are grown for their interesting and spectacular leaves. They come in many sizes, colors and textures, and can be small or large, smooth or veiny, decorated in bold accents of red, copper and silver or subtle shades of green. Yesterday, my head gardener, Ryan McCallister, selected some beautiful varieties to root.
Enjoy these photos.
In my main greenhouse I have a large collection of beautiful begonias, many of which were grown from leaf and stem cuttings. I keep these beautiful begonia plants on a long, sliding table, where they can be watched closely and maintained in a temperature and humidity-controlled space.
Begonias grow best in light, well-drained soil. It’s best to use a pre-made seed starting mix that contains the proper amounts of vermiculite, perlite and peat moss. Seed starting mixes are available at garden supply stores.
Ryan uses these plastic seedling trays made especially for our Urban Cultivator – an automated system that provides a self-contained growing environment with everything the plants need to thrive. These trays are made with indentations for adequate and equal water flow.
Ryan fills four trays with the light soil medium.
Next, Ryan goes into the greenhouse to trim some stems. Rhizomatous begonias range from small, delicate plants with one-inch wide leaves to large, robust specimens with 12-inch leaves. There is no end to the variety of leaf shape, color, and texture in the begonia.
Begonias are considered cool temperature plants and do best in temperatures ranging from 58 to 72 degrees Fahrenheit. I am always on the lookout for rare and unusual varieties. This one has green star shaped leaves with chocolate margins.
Begonia soli-mutata is a compact medium-sized species from Brazil. The heart-shaped leaf colors vary depending on its exposure to bright light, which is why its common name is “Sun Tan Begonia”.
Several of my soli-mutata begonia plants were grown from leaf cuttings off a parent plant. The leaves are highlighted by a fine, reddish hue, which is also seen on the leaf undersides. Here, Ryan uses sharp snips to cut off a healthy leaf stem.
Ryan carefully selects mature stems for cutting, but leave those that are old and have become fibrous or woody.
Any viable leaves that fall off during regular plant grooming or repotting can also be saved for rooting purposes. Begonias are remarkably resistant to pests primarily because their leaves are rich in oxalic acid – a natural insect repellent.
Begonia paulensis has large, shiny, green leaves with an extremely textured surface. It is light green and has a puckered texture. The leaf petioles are densely covered with white hairs. The pattern resembles a spiderweb and gives this species one of its common names, “The Spiderweb Begonia”.
Here are the stem cuttings Ryan collected. Begonia leaves root easily. All one needs to do is snip a leaf, push its stem into potting soil, and keep it moist. After a few weeks, or more, one will start to see new leaves emerge.
Ryan inspects each cutting and trims the stem down to about one to one-and-a-half inches long.
Then he sticks the leaf in the soil so that the petiole is covered but the rest isn’t. The petiole is the part where the leaf connects to its leaf stem.
All begonias can be propagated by rooting stem cuttings, sometimes called tip cuttings. The basic idea is that a plant will clone itself by sprouting roots on a piece of stem that is in a moist growing medium. Many begonias root easily, and one can use the similar technique of rooting them in water.
Ryan plants each one the same way – gently positions the stem and tamps down the medium to hold the cutting upright.
The leaves can be positioned closely together, but not touching.
Here, Ryan has filled four trays with begonia stem cuttings. They are now ready to be placed into our Urban Cultivator.
The seed trays sit over these reservoirs and are automatically watered from the back of the unit. The water is absorbed through the holes at the bottom of each tray.
Ryan uses the Urban Cultivator residential unit in the head house. It takes up the same footprint as a dishwasher and is plumbed to water and electrical in the same way. Each residential machine has two grow shelves for the seed trays and pre-set control centers to ensure specimens get exactly the right amount of water, light, and humidity.
Once placed into the Cultivator, each tray is covered with a humidity dome. The humidity dome remains positioned over the seed tray until germination begins. In about six to eight weeks, we’ll have baby “plantlets” ready to be transplanted into containers. It’s that easy.