Dahlias are remarkably easy plants to grow once you get to know them. One of the best things about them is that they love life. When they are growing in the summer heat, these plants are very strong. This vigour for life makes it particularly easy to multiply your plant numbers by taking cuttings.
When you take a cutting, you take a piece of a plant and grow it into a new plant. With dahlias, cuttings are taken from young new shoots that are grown on in damp compost. It won’t take long for the cutting to grow roots from the nodules where the leaves grow and the small pieces of tuber that come with it. Usually, it only takes a few days.
You can take cuttings from new shoots all summer, but the fastest way for the cutting to root is to take it directly from the plant’s tuber, which is its large underground root that stores energy. In spring, little buds will appear on the top of the tubers where shoots grow from.
Scrape back a little soil or compost to get to the top of the tuber if you want to take cuttings from a plant. Or if you’re planting the tuber in spring, leave the top slightly proud of the soil. You’ll soon see the buds burst into action and grow into new young shoots. You can take a cutting when there are more than one shoot with at least three sets of leaves and a length of 6 to 8 cm.
Dahlias are beautiful summer-blooming tubers that produce showy flowers in many colors. Their versatility and long blooming period make them a favorite for cut flowers. Taking dahlia cuttings is an easy, inexpensive way to propagate more plants from a few tubers. With just a little effort, you can increase your dahlia collection dramatically.
When to Take Dahlia Cuttings
The best time to take dahlia cuttings is in early spring before planting the tubers in the garden. This allows the cuttings time to develop good root systems so they will grow vigorously once planted.
Begin by purchasing a few tubers of choice varieties from a reputable supplier In early March, pot up the tubers in soil and place them on bottom heat of 70-75°F. After 10-14 days, shoots will begin to emerge from the tuber necks. Allow the shoots to grow to about 1-2 inches long with 2-3 sets of leaves before taking cuttings
How to Prepare for Taking Cuttings
Before you begin taking cuttings ensure you have the necessary supplies
- Sharp, clean shears or knife
- Rooting hormone powder or liquid concentrate
- Sterile potting mix
- Cell packs or small pots
- Clear plastic dome or bag
- Bottom heat setup (heating pad, heat mat, etc.)
Moisten the potting mix so it is damp but not soggy. Fill cell packs or small pots with the mix. Use a pencil to poke holes for the cuttings. Prepare the rooting hormone as directed on the package.
Step-by-Step Guide to Taking Dahlia Cuttings
Follow these simple steps for taking dahlia cuttings:
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Use sharp, sterile pruners or a knife to cut a shoot just below the base where it attaches to the tuber neck. Remove all but the top two sets of leaves.
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Dip the cut end of the shoot in rooting hormone powder or liquid. Tap off any excess.
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Insert the cutting into the pre-poked hole in the potting mix. Firm the mix gently around the stem.
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Repeat with remaining shoots, spacing cuttings 1-2 inches apart.
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Label each variety.
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Water thoroughly to settle the mix.
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Cover the potted cuttings with a plastic dome or bag to increase humidity.
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Place on bottom heat between 70-75°F.
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Remove the covering daily to provide fresh air circulation.
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Keep the cutting mix evenly moist but not soggy.
Rooting the Cuttings
Within 2-3 weeks, the cuttings will begin forming roots. Gently tug on cuttings to check for resistance, indicating root formation.
Once well-rooted, cuttings can be repotted individually or kept in cell packs for planting out once nighttime temperatures are consistently above 50°F.
Gradually introduce the rooted cuttings to sunlight and outdoor conditions over 7-10 days to harden off.
Caring for Rooted Dahlia Cuttings
The care for rooted dahlia cuttings is the same as for tubers:
- Plant in full sun
- Space 12-18 inches apart
- Provide average garden moisture and well-draining soil
- Stake tall varieties
- Pinch out growing tips to encourage bushiness
- Deadhead spent flowers
- Fertilize monthly with balanced fertilizer
- Lift tubers after first frost
Tips for Successful Dahlia Cuttings
Follow these tips to ensure your dahlia cuttings root quickly:
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Take cuttings first thing in the morning when shoots are most hydrated and turgid.
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Make a clean cut with sharp pruners just below the tuber neck.
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Keep varieties clearly labeled to avoid mixups.
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Use warm (70-80°F) bottom heat for fastest root production.
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Keep cuttings humid but not soggy until rooted.
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Once rooted, harden off cuttings gradually before planting outdoors.
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Pinch out growing tips once planted to produce bushier plants.
With proper care, cuttings will provide flowering plants identical to the parent tuber by midsummer. Taking dahlia cuttings is a simple, inexpensive way to expand your dahlia collection.
Frequently Asked Questions
Here are answers to some common questions about taking dahlia cuttings:
How many cuttings can I take from each tuber?
Take 3-5 cuttings per tuber maximum. Removing too many shoots weakens the tuber.
How long do cuttings take to root?
Cuttings take 2-3 weeks to develop roots when kept consistently warm and humid.
Should I use rooting hormone on dahlia cuttings?
While not required, rooting hormone speeds up the process and results in a higher success rate.
Can I root cuttings in just water?
Rooting in potting soil is more reliable. Water alone often results in rotting.
When should I plant out my rooted cuttings?
Plant out cuttings once night temperatures are reliably above 50°F and all danger of frost has passed.
Will cuttings bloom the first year?
Yes! Rooted cuttings will bloom identically to the parent tuber by midsummer.
Taking dahlia cuttings is an easy way to expand your dahlia collection. In just a few weeks, you can produce many new plants from a few tubers. With proper care, the cuttings will provide beautiful blooms the very first year.
Find the growing points at the top of the dahlia tuber and wait for it to grow 3 x sets of leaves
The cut bit of tuber on the main plant will dry and heal within a couple of days