Welcome to the fascinating world of rhododendron propagation, where the beauty of flower buds unfolds into lush, vibrant gardens.
In this comprehensive guide, we delve into the art and science of multiplying these stunning plants, ensuring that all gardeners can successfully cultivate new rhododendrons from their existing favorites.
Learn how to identify the best flower buds for propagation, understand the critical steps in the process, and discover the joy of watching new growth emerge from carefully selected cuttings.
Whether youre a seasoned gardener or new to gardening, this guide will equip you with the knowledge and skills needed to propagate these beautiful blooms.
To learn more about growing rhododendrons, check out my guide Rhododendron vs Azalea: How to Spot the Difference.
Rhododendrons are popular evergreen shrubs that produce colorful blooms in spring, Their showy flowers and attractive foliage make them a coveted addition to many gardens
While rhododendrons can be purchased from nurseries, an inexpensive way to propagate more of these plants is by taking cuttings from existing bushes. Rooting rhododendron cuttings allows you to replicate your favorite varieties for free.
Here is a complete, step-by-step guide to successfully starting rhododendrons from cuttings.
When to Take Rhododendron Cuttings
Timing is important when taking rhododendron cuttings. The best time to start cuttings is in mid to late summer when new growth has hardened off. Cuttings taken in July and August will have time to form roots before the plant goes dormant in winter.
Take cuttings in the morning when the plant is fully hydrated. Using pruners or scissors, select healthy shoots from mature rhododendron bushes that are at least 2-3 years old. Avoid taking cuttings from stressed or diseased plants.
Choosing the Right Rhododendron Cuttings
You’ll have the best luck rooting rhododendron cuttings that
- Are semi-hardwood – partly green stem with some woody tissue
- Are 3-6 inches from the tip of upright stems or side shoots
- Have 2-4 mature leaves at the top
- Are free of flower buds
- Are 4-6 inches long
Take 5-10 cuttings to improve your chances of getting a few viable plants.
Preparing the Cuttings
Follow these steps to prep your cuttings before planting:
- Use sharp, sterile pruners or scissors to detach cuttings just below a leaf node.
- Trim off any leaves on the lower half of the cutting, leaving just 2-4 leaves at the top.
- Remove any flower buds.
- Optional: Dip the bottom 1-2 inches of the cutting in rooting hormone powder to encourage root growth.
Planting and Caring for the Cuttings
To plant and care for rhododendron cuttings:
- Fill small pots with a moist potting mix like half potting soil, half peat or perlite.
- Poke 2-3 inch deep holes and insert one prepared cutting into each hole. Firm soil around stems.
- Water in the cuttings, then cover pots with plastic bags to create humidity. Mist often.
- Place in bright, indirect light. East or west-facing windows work well.
- Keep soil evenly moist but not soggy. Water when the top inch is dry.
- Remove bags after 6-8 weeks when you see new growth. Gradually acclimate to direct light.
- Fertilize every 2-3 weeks with diluted balanced fertilizer during spring and summer.
Root Development Timeline
With proper care, rhododendron cuttings will form roots in 2-4 months. Here’s what to expect:
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1-3 weeks: Cutting stays upright, leaves look healthy. Some leaf yellowing and drop is normal.
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3-6 weeks: Tiny new leaves or buds at the tip signal root growth.
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6-10 weeks: Noticeable new top growth. Gently tug cuttings to feel resistance from new roots.
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10-12 weeks: Cuttings should have an established root system and can be moved to full sun.
Troubleshooting Problems
Here are some common propagation problems and solutions:
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Leaves turning yellow: Normal the first few weeks as cuttings use reserves. Ensure new growth forms.
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Stems rotting: Increase air flow, cut back on watering. Remove any diseased cuttings promptly.
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No new top growth: Use rooting hormone next time. Check moisture and light are correct. Discard after 12 weeks.
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Roots but no top growth: Be patient! Growth can take up to 16 weeks. Ensure mix doesn’t dry out.
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Weak, spindly growth: Gradually introduce to brighter, filtered light.
Be patient, as rhododendron cuttings can take 3-4 months to fully root and establish. Following proper techniques will reward you with beautiful new plants.
Long-Term Care
Once your cuttings have successfully rooted, here are some tips for ongoing care:
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Overwinter new plants in a protected area before planting them outside the following spring.
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Transplant into the garden after the last frost, spacing 2-6 feet apart depending on mature size. Choose a site with good drainage and afternoon shade.
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Water whenever the top few inches of soil become dry. Maintain even moisture.
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Fertilize every 2-3 weeks during the growing season with rhododendron fertilizer or balanced 10-10-10 fertilizer. Stop feeding after mid-August.
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Prune only to shape plants and remove dead branches. Avoid heavy pruning.
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Monitor for common rhododendron pests like root weevils, vine weevils, and lace bugs.
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Some leaf drop is normal in fall and winter. Water 1-2 times per month during dry winters.
With proper care, rhododendron cuttings will reward your patience with beautiful, free additions to the garden. Follow this step-by-step guide for propagation success!
Best Time for Taking Cuttings
The timing of taking cuttings is critical for successful propagation.
- Rhododendron Cuttings in Spring: Spring is an ideal time to take softwood cuttings. Softwood cuttings are from new growth that is not yet mature. These cuttings tend to root quickly and easily but are also more delicate and require careful handling.
- Rhododendron Cuttings in Winter: In winter, you can take hardwood cuttings from rhododendrons. These are from mature, woody stems and are more resilient than softwood cuttings. However, hardwood cuttings usually take longer to root and might require a more controlled environment, like a greenhouse.
Can you root a rhododendron branch?
Yes, you can root a rhododendron branch using techniques like layering and air layering.
These methods are particularly effective for larger branches that are still attached to the parent plant.
In layering, a branch is encouraged to root by making contact with the soil, while air layering involves rooting a branch in the air using moist sphagnum moss and plastic wrap.
Propagating Rhododendron from Cuttings
FAQ
Can you root rhododendron cuttings in water?
You can also try growing cuttings in water, although gardeners have had mixed results getting rhododendrons to root in just tap water. Keep the leaves and about half of the cutting above water, and you might see them root in as little as a few weeks. Transplant the rooted cuttings into the garden.
Is it better to propagate cuttings in water or soil?
Some plants will root in water, but cuttings will develop a better root system when rooted in a soil-less potting mix.
How do you encourage the roots to grow from cuttings?
Auxin, a naturally occurring plant hormone, stimulates root formation. Several synthetic forms of auxin are sold as “rooting hormone.” Though some plants will root readily without treatment, application of rooting hormone to the base of the cutting will often improve your chance for success.
How do you propagate a rhododendron?
Sow on surface of soil, cover with a fine sprinkling of vermiculite and propagate at 20-25 degrees C (68-77 degrees F). Do not exclude light, as this helps germination. A clear dome or a heating mat can be used to achieve the proper temperature. Germination should take place in 7-21 days.
Can you cut a rhododendron?
If you have a particularly large or woody rhododendron, you may find it easier to cut it with your handy secateurs. John adds, ‘You need to be really careful not to clip off any new buds as these are what next year’s growth will flower on, and if you cut any off, you risk damaging the plant.’ attest) – especially if you have a small garden.
How do you plant a rhododendron?
Set the rhododendron into the hole with its roots at soil level. Dig a hole twice as wide as the root ball and as deep. Set the plant into the soil, positioning it so its roots are approximately at soil level. Planting the rhododendron below soil level can cause root rot.