Propagating Begonias from Stem Cuttings in My Greenhouse
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 existing stems. It’s an interesting and very easy-to-follow process.
One of the easiest plants to propagate is the begonia. I have a large collection of beautiful begonias in my greenhouse. 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. Last week, my head gardener, Ryan McCallister, selected some varieties to root.
Enjoy these photos.
In my main greenhouse I have a large collection of begonias, many of which were grown from leaf and stem cuttings. I keep these begonia plants on a long, sliding table, where they can be watched closely and maintained in a temperature and humidity-controlled space.
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.
This variety has bright green leaves with dark veining.
This one shows leaves that are silver-gray with green margins.
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 with interesting forms.
During the winter months, the plants flower, but they are mostly prized for their extravagant foliage.
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.
Then he 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.
The stems do not have to be long. The cut should be just below the bottom node, because this is where they will root the best.
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 new leaves emerge.
He places the cut leaves onto the table and carefully separates them.
Ryan inspects each cutting and trims the stem down to about one to one-and-a-half inches long.
This one has attractive round bright leaves with dark margins.
And here is one that is reddish brown.
Here, Ryan 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.
It takes just minutes to set them into the tray of soil mix. Ryan plants each one the same way – gently positions the stem and tamps down the medium to hold the cutting upright.
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.
The leaves can be positioned closely together, but not touching. They are now ready to be placed into our Urban Cultivator.
Inside the head house, we have two smaller counter height Urban Cultivators. 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.
In about six to eight weeks, we’ll have baby “plantlets” ready to be transplanted into containers. It’s that easy. If doing this without an Urban Cultivator, keep it out of direct sunlight, but in a warm, well-lit spot. Mist the soil as needed, so the cuttings stay moist.
And then the young plants will join all these beauties that are thriving in my greenhouse.