Growing zinnias from stem cuttings is an easy propagation method to get new plants. The cuttings can be rooted in water and will be ready for planting in just a few weeks.
Also see 7 Best Tips For Growing Zinnias to learn about best growing conditions, pinching, deadheading, and seed saving.
Propagating Zinnia Cuttings
Zinnias are loved by so many gardeners because these sun-loving annuals produce gorgeous flowers with a long bloom cycle, grow more prolifically with pinching, and root readily from cuttings.
You can grow zinnias from seed or use the instructions below to start new plants from stem cuttings.
- What Is a Stem Cutting?
- How to Grow Zinnia Cuttings
- Planting Rooted Zinnia Cuttings
- Resources | Recommended Books
What Is a Stem Cutting?
Before we get started propagating, it’s good to understand what a stem cutting is so you know exactly which part of the plant can grow roots.
A stem cutting is a piece of stem specifically chosen to root and grow into a new plant. When we propagate this way it is “vegetative” not “sexual” reproduction because we’re simply taking an existing piece of the plant (a “clone”) and growing it separately. No flowering or pollination is required.
On zinnias, the plant has one or more stems. When the plants are young you may notice the stems are slightly hairy. That’s normal.
You’ll also notice the leaves, which grow opposite one another, are “sessile” meaning they attach directly to the stems without their own stalks or peduncles.
On zinnias, it’s this area of the stem where the leaves grow that is capable of also growing roots.
How to Take Zinnia Cuttings
When Should I Take Zinnia Cuttings?
While you can do it any time, it’s the younger cuttings that tend to do better. And you want to allow enough time for the cutting to grow, bud, and flower before the cold weather sets in.
Many gardeners take cuttings for rooting when pinching back their zinnias.
To take cuttings, it’s ideal to wait until your plant has at least 8 to 12-inches of stem with several sets of leaves but is not yet budding or flowering.
This method is similar to the one used to take softwood cuttings from plants like coleus, geraniums (Pelargoniums), and viburnum.
Select a stem with several sets of leaves.
The end of the stem is the “tip” and the place you will make your cut is the “base”.
In this example we’ll choose a stem with three sets of leaves.
Cut the base of the stem from the plant by making your cut just below the lowest leaf set, making a diagonal cut if you can.
Gently remove the lowest leaves, closest to the base.
Place the base of the stem in warm water so the lower two inches are submerged. There should not be any leaves in the water.
Keep in a warm, sheltered location (75°F | 24°C), out of direct sun.
Change the water every day or two.
Roots should appear within 5 to 10 days.
This next image shows the roots after the cutting has been sitting in water for two weeks. You’ll notice a new little leaf also formed at the node. You may also get a few roots further up the stem.
Planting Zinnia Cuttings
Planting Depth: Ensure the top of the roots are approximately a half-inch below the soil surface.
You can plant your rooted cuttings either directly in your garden or into containers.
Keep in mind that zinnias sometimes react to big changes, so give them time to transition, if, for example, the new location is much sunnier than it was when you rooted the cuttings.
You can do this by introducing them the new location for periods of time over the next week or so before planting.
Planting In the Ground
Plant your rooted cuttings directly in a full sun location with good, fertile soil.
Keep watered to ensure the roots get established.
Planting in Containers
You can also grow the cuttings in containers ongoing or for transplanting into the ground later.
Keep in mind that zinnias are sometimes fussy about change, so minimize replanting if you can.
Can I Grow Zinnias Indoors?
Zinnias are not great indoor growers. You may be able to keep them happy by a really sunny window for the summer, but most gardeners say they do so much better outdoors that they would rather grow them there.
You can, however, get short-term blooms indoors.
I took this cutting (below) from a zinnia stem that was just starting to form a bud. I put the cutting in water by a sunny window and two weeks later I got this pint-size flower. It’s about 1/3 the size of an outdoor bloom from the same plant.
It would look very sweet to have a bunch of jars of these tiny blooms lined up on a windowsill.
Once you try it, it becomes routine to root zinnias and get lots of new plants growing around the garden.
As things bloom, remember to mark your best flowers with a ribbon and leave them for seed saving. This shows how to harvest zinnia seeds.
~Melissa the Empress of Dirt ♛