I have taken cuttings from my Coleus plants and rooted them in water. They now have about 2 inches of fine roots growing. I’m planning to overwinter them. Should I pot them up in potting soil now?
According to Coleus: Rainbow Foliage for Containers and Gardens by Ray Rogers (Timber Press, 2008), growing Coleus from cuttings (rooting them, as you did, in water) is a fine way to propagate more plants. The cuttings will survive for weeks or even months in nothing but water, and with soluble fertilizer, this time could even be extended.
However, since you want plants which may eventually live somewhere other than the windowsill or counter, Rogers recommends removing the cuttings from the water when roots are an inch or two long, and planting them in growing medium. This is because roots which are produced in water are less sturdy, so making a transition to growing medium helps the plant develop. (Long water roots are easily damaged if pressed too hard when potting them up.) As for the potting medium, even garden soil can be used if it is not heavy clay and does not dry out. Since you are going to keep your plants indoors over winter, you may want to use purchased potting mix which has an open structure (drains well but will not dry out too fast). The mix might include bark, coir, perlite, pumice, or other ingredients. The author has a preference for vermiculite, but be careful to wear a dust mask when handling any fine materials; you definitely don’t want to get particles in your lungs.
Once you’ve potted the cuttings, keep the medium moist but never soggy, and keep them humid (using a mister, for example). Cuttings need bright light but not direct sun, and should be kept at about 70 degrees. If room temperature drops below 50, you may want to set the pots on a heating mat. You don’t need to add fertilizer while the cuttings are getting established. You can move the cuttings into larger pots once they’ve developed a strong root system (at least a week).
Other tidbits of information that may be useful:
- Cuttings can be taken from any piece of stem on the parent plant, but it’s best to choose stems which are neither the youngest nor the oldest growth.
- Cuttings taken from the sunnier side of the plant have firmer tissue and may root more strongly than cuttings from the shadier side, but they will also need consistent humidity and protection from intense sun while rooting.
- Cuttings will look like the parent plant if the parent plant is a genetically stable cultivar, but some cultivars (especially with pale pink in the center of their leaves) are more prone to reverting or sporting.
- Once night temperatures outdoors are above 60 degrees, it should be safe to move your plants outdoors (but it’s always a good idea to harden them off gradually beforehand).
I have a Euphorbia trigona houseplant which is about 6 feet tall and quite thin. It has gotten weak and is bending. It looks like it is going to break. I have read it can be propagated by stem cuttings. I don’t know if this means cut the end off OR cut several sections of the stem. If I just cut off the end will the original stem survive?
According to Indoor Gardening by Kate Jerome (Pantheon Books, 1995), Euphorbia trigona often becomes top-heavy, which sounds like what is happening to yours. They do tolerate pruning well and may branch out from the place where you prune. Do be very cautious in handling this plant, and be sure to wear gloves: it has a toxic sap that can cause skin irritation. Generally when cuttings are taken, they are from the tips, where the new growth is occuring, but you can also try several cut pieces of stem. Ordinarily not every cutting is able to form roots, but according to The Complete Houseplant Book by Peter McHoy (Smithmark, 1995), you can increase your chances of success by letting the cut ends of the stem dry out in the air before putting them into potting soil.
My indoor Dracaena is getting too tall. I’d like to prune it, and maybe use the cuttings to start new plants. How do I do this?
You should be able to do both tasks. The Complete Houseplant Survival Manual by Barbara Pleasant (Storey, 2005) says “when plants become too tall, cut off the cane at any height. New leaf clusters will grow from just below where the cane was cut. You can cut sections into 6-inch pieces and root them like stem cuttings.”
You might also find this discussion from University of British Columbia Botanical Garden’s online forum useful.
Here is more information, from University of Florida, which describes how pruning will result in two or more branches forming where the pruning cut was made: “Cut one or two of the stems to a point where new foliage is needed.”
What is the purpose of the chemical in store-brand rooting hormone? I’d rather not use anything with chemicals when I’m propagating plants. Are there alternatives?
The chemical in rooting hormone (usually Indole-3-Butyric acid) acts as a growth stimulator. In commercial rooting hormone formulations, it may be combined with fungicide to prevent the development of fungus/fungal diseases during the rooting process, as is the case with a common brand, Rootone, which contains Thiram (a fungicide). The Environmental Protection Agency has more information about Indole-3-Butyric acid.
If you would rather not use synthetic rooting hormone, you can skip this stage altogether, or you can try making willow water to encourage rooting instead. Oregon State University (now archived) explains how to make a rooting tonic using willow.
Can you tell me how to grow Hibiscus from cuttings?
According to the American Horticultural Society, most hibiscus root easily from cuttings. They suggest the following in Plant Propagation (1999, p. 131 and pp. 100-101):
“…cuttings should usually be 1.5 to 2 inches long, with two or three pairs of leaves retained at the top…remove the soft tip from each cutting, because it is vulnerable to both rotting and scorch…remove the lowest pair of leaves to make it easier to insert the cutting into the medium…make a hole in the medium with a pencil…[for]…minimal resistance…the cuttings will benefit from a warm, protected environment…when the cuttings root, knock them out of the container and gently pull them apart. Pot singly…”
The AHS suggests using rooting hormone and they also point out that due to timing, you may get ‘greenwood’ (slightly hardened) rather than ‘softwood’ cuttings; they are treated the same way.
North Dakota State University Extension has propagation directions including from cuttings.
I also looked at Houzz (formerly GardenWeb), a gardening forum where experienced gardeners share their knowledge. Here is another link from this site which suggests layering, a process by which you bend a branch down to soil (usually in a pot), anchor it, and wait for it to take root.
Here is additional information about layering hibiscus, from Hibiscus World.
A list of the best books, articles and websites on plant propagation.
Make new plants by taking softwood cuttings. Cuttings Through the Year, a booklet published by the Arboretum Foundation(available for sale at the Washington Park Arboretum gift shop) suggests which plants to propagate month by month and how to do it. A few September plants include:
Rock Rose, Salal, Lavender, Holly, Penstemon, evergreen azaleas, Sweet box, Salvia, California Lilac and many others.
For a tutorial on taking softwood cuttings go online to a Fine Gardening article complete with clear color photos: www.finegardening.com/propagate-your-shrubs-softwood-cuttings