List of Herbs You Can Root in Water -- with Instructions

Rosemary rooted over the winter in a sunny window.

Propagating herbs from cuttings is part of the fun of growing them in the first place, and many herbs are very easy to reproduce. Most articles on herb propagation recommend placing cuttings in an inert, loose growing medium like sand,  vermiculite, perlite, coconut coir or likely a combination of the three, and then letting the plants root over a period of weeks or months -- depending on the herb or plant variety involved.

This is usually the most reliable and sensible way to exactly reproduce a plant, because cuttings are clones, or mini-me duplicates.  Some of the plants sold in large garden centers every spring are produced this way rather than from seed. Using a gentle growing medium helps encourage strong roots, and some growers hedge their bets by dipping the cut stems in a rooting hormone to enhance root development.  You can use this classic method with a setup as simple as:

Classic Bag and Media Plant Propagation Method - What You'll Need

• Cuttings - Prefer new growth around 6 inches long. Cut stems on a slight diagonal and remove three quarters of the leaves from the lower portion of the cutting.  Cuttings may require scoring, depending on the variety.
• Potting mix - Prepared potting mix, plant starter or a mixture of the media above to a depth of three to four inches.
• A plastic freezer bag - Medium to large
• Enough water to keep the media moist -- replenished every week or so
• Rooting hormone (optional) - There are DIY options like willow water, pure honey and powdered cinnamon. If using hormone, roll the stems in the mixture before planting.

Directions

1. Add soil to the bag.
2. Prepare the stems.
3. Add the stems and firm the top of the soil gently. I usually add no more than three cuttings per bag.
4. Blow into the bag and seal it.
5. Open the bag once every few days for a few hours and water slightly if the soil looks dry.
6. Avoid jostling the bag as this will disturb the roots and may create fissures.
7. Check for rooting after a few weeks by tugging gently on the cutting. Some herbs like rosemary may take 8 weeks or more to root, so be patient.
8. Transplant new herbs to three inch pots when their roots are an inch or so long. You can often discern root development by inspecting the soil through the transparent plastic.

Herbs You can Root in Water

There are actually a number of ways to root cuttings successfully, including using hydroponic or aeroponic cloners.  A very simple method, which can be used on some but not all herbs, is to simply place the cuttings in a glass of water and wait for something good to happen. Consider this the minimalist approach. If you want to play with propagating cuttings, this is the easiest way to start.

A word of warning: This is not a popular option among experienced gardeners. It is widely believed roots grown this way are weak and the subsequent plants less robust.  I've had success growing plants in water, though, and it’s a lot of fun. The resulting transplants have been pretty successful for me, too. I've always made water rooting a three step project, though. More on this in a minute.

List of Herbs You Can Root in Water

 Here are some herbs that can be rooted in water:

• Basil
• Lavender
• Lemon balm
• Lemon verbena
• Marjoram
• Mint
• Oregano
• Pineapple sage
• Rosemary  
• Sage (common)
• Scented geranium
• Stevia
• Thyme

You may also have luck with:

Savory (summer and winter)
Bay laurel  (This one is a two step process. Soaking in water encourages bumps or nodes on the underwater portion of the stem that will then make a bay cutting easier to propagate in soil. If you've had bad luck cloning bay, give it a try.)

Prepped cuttings from left to right: oregano, rosemary, lavender

I've typically started herbs in water from spring to late summer with the idea of maintaining them indoors until fall or, more likely, the following spring. Although I started out using a sunny window, the volume of plants increased so much that I eventually invested in a fluorescent grow light setup, which works well. I concern myself less with the type of cutting (softwood or semi-hard) than I do with choosing a stem that hasn't flowered but is growing well. This shows me it is robust and can produce roots. If I'm trying to propagate a houseplant, say, I put it outdoors early in spring to try and give it some extra energy that will then enhance root development in cuttings harvested from that plant.

This works for me:

1. Choose 4 to 6 inch non-blooming stem cuttings on healthy plants that are not currently dormant (not yet actively in a growth phase).
2. Cut each stem on a slight diagonal with a sharp knife. (A sharp knife will help reduce damage to the stem. Avoid using scissors, which tend to crush stems. For plants, crushed, compressed or damaged stems are a little like trying to suck soda from a bent straw. You wouldn't wish that on any seedling in training. Oh, craft knives, razor blades and box cutters also work well.)
3. Remove leaves from about two thirds of the cutting.
4. Place the cutting in water in a small glass, cup or jar with the water topping out just below the lowest leaf on the stem. If possible, some of the leafy top of the seedling should peek over the top of the container. This isn't essential, but helps with airflow.
5. Prefer one cutting per cup as this will avoid the problem of tangled roots later . . . . Okay, so three stems at most.
6. Place the cup in a window that receives at least four hours of light, but no direct sunlight, a day.
7. Change the water in the cup EVERY day. This is the most important rule in the process.  Changing the water frequently helps control the growth of bacteria and algae. The cleaner the water, the more likely your cutting will root and thrive.
8. Once roots have developed on the cutting and grown to about a half-inch to an inch, transplant it to a three inch pot that contains a 50/50 mixture of potting soil and perlite or something similar. 
9. Maintain the pot indoors or in a greenhouse for at least a month before acclimating it to the outdoors.
10. The three steps above are: rooting, potting and transplanting. With seasonal limitations, this can sometimes end up being a long process -- but not always. Fast rooting herbs can sometimes take as little as two weeks, while slow rooting varieties like rosemary and lavender can take two months or more.

Notes

Rooting times vary from herb to herb. Even cultivars within an herb family will respond differently.

For the best results, start with a number of cuttings of the same plant variety -- just in case.

I don't cover the glass with a plastic bag (like a mini-greenhouse) because I think good air flow is important, but if the air in your home is dry, you may want to consider it. If you do use a top covering for your cuttings, make sure it doesn't actually touch the leaves. An inverted sandwich bag taped to the glass (dome like) works well for this.

If your goal is to transplant water rooted cuttings directly into the garden, alter the rooting setup somewhat: Place a layer of gravel on the bottom of the cup before you add the water and cutting(s). The gravel layer should be just below the base of the stem.  The cutting will root directly into the gravel (or coarse sand), which will help encourage branching roots and stronger root development overall. This can be useful for fast rooting plants like those in the mint family that can be rooted and planted over the course of a single season.

Rooting plants in water is fun and doesn't require any special equipment, accessories or supplies. All it takes is a sunny window, a vow to change the water daily and some patience.  Try both techniques and see which you prefer.



References

DeBaggio, Thomas.  "Water Works: Rooting Cuttings in Water." 1994. http://www.motherearthliving.com/gardening/water-works.aspx?PageId=1

Juniper Moon Farm. "Propagating Lavender." http://www.fiberfarm.com/2013/02/propagating-lavender

Plant Village. "Marjoram." https://www.plantvillage.com/en/topics/marjoram/infos/diseases_and_pests_description_uses_propagation

Photo 1 - Water Rooted Ficus Cutting
By Biusch (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons  https://upload.wikimedia.org/wikipedia/commons/3/3e/Ficus_cuttings_with_roots_in_a_bottle%2C_White_background.jpg https://commons.wikimedia.org/wiki/File%3AFicus_cuttings_with_roots_in_a_bottle%2C_White_background.jpg

Other photos by author