In cooler parts of the country, like here in Ohio, fall ushers in a dramatic change of the landscape. The first frost brings an end to the life of tender plants, changes in the coloring of trees, shrubs and perennials and a life inside the hive for my bees.
For me, the first frost is a milestone for preparing for next spring. In the weeks leading to the first frost, I take stem cuttings of coleus, sweet potato vines, geraniums, and other herbaceous tender plants — commonly called annuals — to propagate them for planting next spring. This allows me to save money on plants and continue growing my favorite varieties year after year.
Why not try this project yourself? This is a great project for teaching the kiddos about Mother Nature. Indoor plants boost indoor air quality, and, care of them nurtures one’s soul. Though this process will work for many kinds of plants, coleus are among the easiest.
Follow the guidelines below and you’ll be blessed with plenty of these lovely ladies for your garden next spring. The bees and other pollinators will appreciate your efforts too. They flock to the pretty purple and pale blue spikes that sprout on coleus in late summer and early fall, typically a dearth (nectar and pollen deficit time) here in central Ohio.
Coleus and sweet potato vines propagated from stem cuttings last fall. They will serve as parent plants for next year’s plants. This practice also allows me to exchange plants with fellow gardeners. The bright green coleus on the right started as a stem cutting from my sister many years ago.
Gather Your Supplies
I like to do this process assembly-line style on a warm afternoon. You will need:
- Flower snips or sharp scissors
- Parent plant
- Potting mix
- Large mixing bowl or bucket
- Water
- Trowel
- Rooting hormone
- Insecticide (optional)
- 4″ pots or small containers with drainage holes in bottom
- Saucers or tray
- Mulch or pea gravel (optional)
Supplies you will need to take stem cuttings. I enjoy this process because it connects me to my heritage. My family tree includes farmers, generation-after-generation, and matriarchs who tended beautiful flower and vegetable gardens. The vintage mixing bowl on the right is from my great-grandmother.
Prepare Your Pots
First, prepare your pots or containers. Pour potting mix into a large mixing bowl or bucket. Add a small amount of water and mix with trowel. Continue adding water and stirring to create a damp, evenly moist mixture. Ensure there are no pockets of dry or boggy soil. The potting mix is much like a sponge at this point. It will repel water when dry and is nearly impossible to moisten unless done from the onset.
Add potting soil to the brim of each pot as it will compact later, as plants are watered.
Always looking for ways to re-purpose and re-use, I save plastic pots, like those above, from previous nursery purchases. I have amassed quite a collection over the years and reused them many times over. If you don’t have pots like these, use plastic cups or food containers, like yogurt cups, with several holes poked in the bottom for drainage.
Choose Parent Plants and Take Cuttings
Select healthy, well grown plants as parents from which to take stem cuttings. Ideal candidates have new growth, stout stems and few, if any flowers. Avoid blemished, diseased plants.
I try to beat the frost by at least two weeks because the closer to this date I am, the more difficult it is to find healthy, disease-free plants. They tend to go downhill quickly as the first frost date approaches.
With your flower snips, take a stem cutting about 6-7″ in length with 3-4 nodes of leaves. A node is the place along the stem where a new leaf attaches. If you have a choice, opt for stems with nodes that are closely spaced as this enables you to take a shorter stem cutting. This will create a stockier, less straggly stem cutting.
Cut off or carefully strip the bottom leaves from the nodes. Cut the bottom part of the stem again at a 45-degree angle (for maximum root growth opportunity). Make sure you are left with a cutting with 1-2 pairs of leaves at the top and 1-2 nodes without leaves at the bottom. If you take a stem cutting with a flower stalk or the beginning of one, snip this off. Do this so the coleus will direct energy towards the development of roots rather than flowers. Roots will develop from both the nodes and the stem end.
Dip stem in water and then in rooting hormone. Shake off excess rooting hormone as excess product may hinder root development.
Planting Your Stem Cuttings
Make a hole in the soil slightly larger than the stem with your scissors or a pencil. Place stem cutting in hole and push to the bottom so leaves are just above the soil line. Firm soil around stem with your fingers, then water. Place additional soil in depression and compact slightly.
To increase odds for success, plant multiple stems in a single pot. I usually do this with sweet potato vines and geraniums.
If desired, top soil with a thin layer of pea gravel or mulch. This more evenly disperses water as plants are watered and helps to retain moisture.
Spritz stem cuttings lightly with insecticide if desired to kill potential pests. Though I don’t always do this with coleus, I almost always do with sweet potato vine, which is susceptible to insects no matter how or when I take cuttings.
Some people also cover stem cuttings with plastic bags to retain moisture while roots are established. I have had much success without covering them, so do not do this. If you do cover them, make sure the bag is placed loosely over the plant, but not tied, and remove it should condensation form on the inside. Replace the plastic bag a few hours later, when moisture buildup is gone.
As well, some people start plants in smaller pots and transfer them to larger pots when they begin to root. I prefer to use larger pots from the start as there is less chance for them to die during transplant. My coleus are grown in these 4″ pots just until mid-May, when they will be moved outside permanently. To overcome rooting failure, I may plant multiple plants in each pot or start with more pots.
The stem cutting on the left is the best of the bunch here. Notice the nodes are closely spaced, the stem is stout and the leaves are fairly small. For this cutting, I will strip leaves off the bottom three nodes and cut the stem to leave the bottom two nodes, then dip in rooting hormone and plant.
After Care
After planting, set pots in a cool location with dappled or indirect light for several days. Then bring them to a more spot with bright, indirect sun and steady, cool temperatures. Don’t expose them to full sunlight until new leaves begin to appear. Typically new leaves will begin to grow in about 2-3 weeks.
I usually place stem cuttings in my garage for several days. Here, they are out of the heat and sun, but get some indirect light from a few windows. Then I move them to windowsills on the east and west sides of my house, where they will remain until spring.
Don’t be too concerned if some plants wilt initially. You may notice they wilt during the heat of the day, then recover at night. When they become hardened to the heat, they will no longer wilt. Wilting is more common with smaller, softer stems. As well, I have noticed some varieties of coleus are more likely to wilt than others.
Water when soil becomes dry, making sure area around stems remains most. But, be careful to not over-water. More indoor plants are killed by over-watering than under-watering. As plants become established it is better to water less frequently, but more deeply. Remove dead leaves and plants that die. As well, clip flower blooms.
Stem cuttings in their new homes shortly after planting. Notice the leaves on some of the pink coleus at the bottom have wilted slightly. This is common with this variety. They will eventually overcome wilting when they begin to root. Coleus varieties include Trusty Rusty (top red), Coleosaurus (middle green with red veins) and Kong Rose (bottom pink centers).
Next Spring
Before planting your coleus in their permanent homes in the spring, they will need to become acclimated, or “hardened,” to outdoor weather. Gradually transition them from indoors to outdoors by increasing their time outside.
Start with just a few hours outside in a shady spot. Then increase the amount of time and exposure to sun gradually over the course of 7-10 days.
Often, I will move plants still in their winter pots to their summer location for several days before transplanting. This allows me to move them should they need intervention.
A note to northern gardeners: don’t jump the gun to get a start on spring and summer. I used to plant as soon as possible but now wait a bit longer. I deal with fewer cut worms and unexpected frost by paying head to the last average frost date (right around Mother’s Day here). I also put “collars” made from plastic cups or milk cartons around plants the first several days after planting to prevent cut worm damage.
Coleus and begonias in the process of being hardened to outdoor weather in early spring.
Additional Notes
This is a relatively easy process to accomplish with coleus, geraniums and begonia. It is a little more challenging with sweet potato vines, but can be done.
Experiment and learn. You are bound to have some failures the first few times, but don’t give up. Just take a few more stem cuttings than you need. I usually take about twice as many cuttings as I need for the spring. In that way, if I get extras, I have plants for friends or can be generous with my pots.
You can also propagate stem cuttings by placing them in a glass of water, then transplanting to a pot with potting soil after they sprout roots. Coleus and sweet potato vines are extremely easy to root this way. In fact, sweet potato vines will get roots within days.
However, I find it challenging to transition stem cuttings from water to soil, so now plant in soil from the start. It may take a little longer for roots to take hold. But I obtain a higher rate of success with this method.
For additional information on propagating other kinds of plants, read this article from the North Carolina Extension Service. For another take on taking stem cuttings from soft plants, read this article from the Missouri Botanical Garden, an excellent source for information on plants of all kinds.
