Plant propagation

Rooting Coleus In Water

An easy way to propagate many plants is to root the stems in water. Since I’m particularly fond of Coleus, we’ll just use them to explain the technique.  They are  easy to grow and I love the wild color palette of the many varieties. You can expand your existing plant collection, or save your favorite varieties by taking cuttings and rooting them in water. This technique works for other plants too, but I’m addicted to Coleus!

This practice is especially helpful at the end of the outdoor growing season, and before the frost takes your plants. Your plants will be growing vigorously and your cuttings will be strong and healthy.

A few of the plants in my greenhouse.

Beware of “Hitchhikers”

You can bring the whole potted plant inside but beware of “hitchhikers”-slugs and bugs may have made a home in your potted specimen. Upon bringing it indoors, it would be best to isolate the plant in a sunroom or garage while you check for pests. Best practices should include: examining the whole plant, spraying the plant with a stream of water before bringing it in, or spraying with an insecticidal soap if insects are present. Mealy bugs seem to like coleus. Remember that some pests might be living in the soil, such as slugs or fungus gnats. 

Your best bet is to remove the plant from its container, clean the plant and pot, and then replant in fresh potting soil. This should eliminate travelers. If your plant still looks good, this is the method I would recommend. This holds true for any plant you are bringing indoors, including newly purchased houseplants. Alternatively, it’s not a bad idea to just scrape off the top inch of soil and replace it with new soil. This will take care of fungus gnats. You could also add a layer of much, as in small bark chips, colorful gravel, etc.

Summer Cuttings

If at the end of Summer your plant is declining in vigor and appearance, you might be better off taking a tip cutting or two. This is done by selecting the best-looking tip of the plant and cutting off a 4-6 inch piece of stem and inserting in water.  Roots will begin to grow at the node (where the leaves come out), so cut below the leaf node and remove the lower leaves. It’s a good idea to remove the largest upper leaves too, so as not to stress out your cutting by those leaves trying to photosynthesize.

A few tip cuttings.

If you take cuttings in summer when plants are more vigorous, cut above a node and new leaves will grow from the tip on the “mother plant”. This way you will not have a stem with no leaves. You can then trim your cutting as above.

If your coleus has begun to flower, that is an indication that the plant is going to seed and may become less attractive in appearance and vigor. Pinching or cutting off the flowering part will allow the plant to put energy into leaves. The flower’s job is to make seeds and this will signal the decline of that plant’s life, having finished its job. It’s a matter of taste whether to remove the flowers, but that’s what I do. Often flowers get pinched off with a thumbnail, and thus, Coleus is sometimes known as a “pinch plant”.

What to Do With Cuttings

Now that you have cuttings to place in water, just remove the lower leaves so that none are underwater causing the growth of bacteria. Change the water every few days and pot up the new cuttings when the roots are ½ to one-inch long. I’ve found plants with large root growth will not adapt as well to growing in soil. Keep the cuttings planted in moist soil until they adapt to life in the soil.

You can also keep your cuttings in water indefinitely, but your best-looking plants will be the new cuttings you have grown in soil.

Well-rooted cutting in winter.

In the dark Winter months, any additional lighting system will keep your collection looking good. If this is not possible, find the sunniest south window you can and remember to rotate the pots for even growth.

Another easy method I’ve found is to root  plants in an Aero Garden. Just set your tip cuttings in the holes, making sure a leafless stem is in the water. The upper leaves will hold the plant in the hole, and the light is on a timer, so everything is pretty much done for you. I have several Aero Gardens and you can often find used Aero Gardens online or ask a friend if they have one they aren’t using. Check the website if you need new lights.

Collection of cuttings in a vase.
Rooting globes from Gardener’s Supply.

Coleus is an easy plant to grow and they are great for kids to experiment with. Taking cuttings is easy, as is rooting them in water. Roots may appear in just a few days. You can use any bottle or jar for rooting and line them up on a bright, south-facing windowsill so you can have color all Winter.

Warning! Coleus growing is slightly addictive!

Take a look at Terra Nova Nursery website (www.terranovanurseries.com) to see some great plants. Check out pages 2 and 3 under the Products category. Don’t say I didn’t warn you about the addictive nature of this plant!

Patrick Ryan is an Alaska Master Gardener and the Education Specialist for the Alaska Botanical Garden. A retired elementary school teacher, Patrick is a member of the Anchorage Community Forest Council and sits on the board for Alaska Agriculture in the Classroom.

5 comments on “Rooting Coleus In Water

  1. Mary L Discuillo

    Can someone pls tell me how much light they need when outdoors. Can they tolerate hot south sun or what is best. Thanks.

    • Patrick Ryan

      I’ve found that a little shade is good, but adequate sun brings out the best leaf color. It seems to me Coleus used to be considered a shade plat, but after I saw them at the botanical garden in Nashville, in full sun and warm temps, I started acclimating mine to full sun. That’s generally 6 hours of sun.

  2. Thank you for the very helpful article. I plant 3 different coloured coleus – light green to dark burgundy, in one large pot in the spring where they receive afternoon sun and they are beautiful together all summer. By fall they are HUGE and last till the frost takes them (except the clippings I remove!).

  3. Margaret

    Thank you for the clear instructions. I am new to coleus and loved the brightness of my first-ever plant that just shone through the winter. I may welcome a new addiction with all the great colours and patterns.

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