There are two easy ways to propagate kohlerias.  Kohlerias are very fast, vigorous, growers, producing lots of new growth both above and below soil level.  This means there's always lots of material with which to start new plants.  What follows are the two most common means of propagation.

 PROPAGATION BY TIP CUTTINGS

Seen at left is a large, overgrown kohleria in a 4" pot.  This one was grown on a crowded windowsill leaning up against the window.  We could "stake" it, but it's already taller than we would like. 

Instead, we'll start over, making a "new" plant with cuttings from this one.

Step #1:  Creating the cuttings.

Each of the long stems shown in the photo above can produce a number of cuttings.  Shown at right is one of the stems, with the parts separated.

At top is the cutting which we'll use to start a new plant.  The flowers and buds have been removed, as well as the lowest pair of leaves.  Once rooted, new roots will develop from the leaf "nodes" where the lower leaves were removed.  Removing the flowers and buds encourages faster the tip to root and grow faster (i.e. produce roots and leaves, not blooms)--don't worry it will bloom soon enough once rooted.

We'll discard the lower portion of the stem but, if you desired, you could cut this into sections, and root each of them.  For each section, keep one pair of leaves at top, and remove the pair of leaves below.  Though each section won't have a growing tip, it will soon produce one (or more) from that point once rooted.

Step #2:  Rooting the cuttings.

Since we want to have a "full" plant in a short time, we're going to root 3 large tips into one 4" pot, which we've filled with our regular potting mix and moistened well (damp but not soggy).

Kohlerias are relatively soft-tissued and will root very easily, with or without rooting hormones or gels (as shown here).  Make a narrow, deep hole (with a pencil or tweezers), insert the cutting, and firm the soil around it.

Step #3:  The finished product.

Shown at right is our "new" plant!  Three large tips have been rooted into one 4" pot.  The pot has been labeled with the proper name.  To encourage quick rooting, the entire pot and plant can then be placed inside a clear, plastic bag and put in a bright (not hot) location.  Tips should be well rooted in 4-6 weeks, at which time the bag can be removed and the plant placed where you intend to grow it permanently.

PROPAGATION BY RHIZOMES

Nature has given kohlerias (and other rhizomatous plants) an "insurance policy" against severe conditions (or your neglect).  If conditions are so harsh that the plant can't survive, it will go dormant, with all the growth above the soil appearing to die.  The rhizomes beneath the soil (shown at left) however, may survive, waiting for good conditions to return, at which time they will send up new growth. 

Step #1:  Collecting rhizomes.

On older plants, there can be quite a number of rhizomes--they will look like hairy worms with scales. 

Each of these scales, in fact is capable of producing a new plant--if you want more plants, you can break each of the rhizomes into smaller pieces.

Step #2:  Storing the rhizomes.

You could choose to just leave the rhizomes in the pot, and wait for new growth to appear. We prefer to simply store the rhizomes.  Fill a clear, plastic baggie with some moist (not wet) soil and add rhizomes (and a label with the proper name of the plant), seal the bag, and place in a bright (but not hot) location. 

Step #3:  The "sprouting" rhizomes.

When the rhizomes are ready, they'll sprout and begin to produce new growth.  This may happen soon, or it may take many months for growth to appear, though kohlerias are usually pretty quick.  The best time to remove plantlets (with attached rhizome) for potting is when they are still short and thick-stemmed.  The bag on right is well past that time.

Step #4:  Separating plantlets

Gently separate each individual plantlet, keeping the rhizome attached, if possible.  This plantlet has been in the bag a bit too long, and has gotten long and leggy--we'll need to "roll" it.

Step #5:  "Rolling up" the rhizome and plantlet.

Since the plant attached to this rhizome has gotten too long and leggy, we need to "roll up" the plantlet before potting it.  Do this in the same way as you would a larger plant, except here we roll the stem around itself and it's rhizome (it will make a much smaller "ball").  Had the plantlet been removed from the bag earlier, it would have been much shorter and may not have needed rolling up.  If you have a hard time keeping the ball "wound", you can do what we've done here--using rubber band to keep it together.

Step #6:  Potting the plantlet.

Fill a small pot (2 1/2") with moist soil and make a small hole in the center.  Drop the plantlet into the hole and gently firm soil around it, then lightly water.  Label the pot with its name.  The "finished product" is at right.

Other rhizomatous gesneriads.

These same procedures can be used for most any of the rhizomatous gesneriads, such as Smithiantha, Eucodonia, xSmithicudonia, Achimines, Diastema, Niphaea, to name a few.  All are fast, vigorous, growers that may go dormant if subjected to extreme conditions or neglect.  All will readily produce rhizomes (whether or not they go dormant) and can be propagated, groomed, and repotted in the same manner as Kohleria. 

Like to have some of these plants in your collection?  We grow many different genus of gesneriads, many of which are rhizomatous, and often have them available though this web-site--keep an eye on the "specials pages".  If you'd like to learn even more about rhizomatous gesneriads, consider joining the American Gloxinia and Gesneriad Society.