How to propagate dahlias?

Rooting Dahlia Cuttings: How To Take Cuttings From Dahlia Plants

Dahlia tubers are expensive and some of the more exotic varieties can take a substantial bite out of your budget. The good news is, you can get a real bang for your buck by taking dahlia stem cuttings in late winter. Taking cuttings from dahlias can net you five to 10 plants from a single tuber. Let’s learn more about growing dahlia cuttings so you can enjoy even more beautiful dahlia plants each year.

Propagating Dahlias by Taking Stem Cuttings

Want to try your hand at rooting dahlia cuttings? Just follow these simple steps.

Bring your tubers out of winter storage in late January or early February. For growing dahlia cuttings, choose the firmest, healthiest tubers.

Place the tubers in a plastic bag and put the bag, with the top open, in a warm room for a couple of weeks. Note: This step isn’t absolutely necessary, but allowing the tubers to warm in this manner will speed sprouting.

Fill a plastic planting tray to within an inch of the top with damp potting mix or a mixture of half peat moss and half sand. For best results, use a tray with a depth of approximately 6 inches. Be sure the tray has several drainage holes. (If you’re only planting a few tubers, you can use plastic pots instead of a tray – one pot per tuber.)

Plant the tubers in rows about 4 to 6 inches apart, with each stem 1 to 2 inches above the surface of the soil. Write the name of each dahlia on a plastic label and insert it next to the tuber. You can also write the name directly on the tuber before planting, using a regular pencil.

Place the tubers in a warm, sunny room, but avoid direct sunlight. You can also place the tubers under fluorescent lights. Allow about 9 inches between the top of the tubers and the light.

Keep the planting medium slightly moist. Watch for eyes to appear, which generally takes about seven to ten days. However, some may sprout sooner, while others may take a month or more.

When the shoots have three to four sets of leaves, they are ready to take cuttings. Use a sharp, sterile craft knife or razor blade to slice off a shoot with a narrow sliver of tuber about the width of a dime. Cut above the lowest node or joint to leave a bud on the tuber.

Place the cutting on a clean cutting board and use the sharp knife to remove the lower leaves. Leave the top two leaves intact. Dip the bottom of the cutting in liquid or powdered rooting hormone.

Place each dahlia cutting in a 3-inch pot filled with a mixture of half potting mix and half sand. Place the pots in a warm room or on a warm propagation mat. You can also place them on top of a refrigerator or other warm appliance. Water as needed to keep the planting medium moist, but not soggy.

Watch for the cuttings to root in two to three weeks. At this point, you can allow them to develop a bit more, or you can plant them outdoors if weather permits.

New shoots will form from the remaining bud on the original parent tuber. After about a month, you can take more cuttings from the tuber. Continue taking cuttings until you have all you need, or when the cuttings are weak or too thin.

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Propagate Dahlias from Cuttings, a great way to get more for free. Fill in a large bed with Dahlias and keep to your budget or give away to friends.

I love Dahlias, and in this post I show you how to propagate dahlias from cuttings! It is quick and easy.

Dahlias are a new favorite in my garden. I had avoided them in the past because I felt they were too much work. I did not relish the idea of having to dig them up each Fall and pack them away for the winter.

But that has changed completely and now that I am a dahlia convert I want MORE. More colors, varieties and sizes. They perform so well in the late summer garden and the more you cut for bouquets the more they pump out new blooms.

So how do you get more of what you love?

Propagate Dahlias from cuttings!

A step by step video available at the end of this post

It is well known that you can divide dahlias in the Fall and store the tubers (bulbs) for next season but you can also propagate your Dahlias in Spring.

Want a downloadable PDF of this step by step info..

Plant Dahlia tubers in containers

Start with plump, healthy tubers. In my examples I used a planting box I built (). And lower down you will see I also used a plant tray. The soil need not be deep but you will need to have it in a bright and protected area where it is warm.

March is a good time to get Dahlias started like this so your cutting starts are a good size when it is time to plant your dahlias out in the garden.

Dahlia tubers can be awkward as they remind of me of an octopus but you can simply place them on top of the soil and sprinkle more on top. You want the upper part of the tuber to be above the soil line. You will see why later.

Below is the planting tray. You may note that some of the tubers were already sprouting, this is the way they came out of the bag. Good thing I got them planted when I did, they were anxious to get growing.

I gave them a few weeks to grow sprouts and some leaves.

How to Take the Dahlia Cuttings

These two are perfect for cuttings. In fact anything about 3 inches or so are good.

I take a sharp knife and I cut into the tuber, just below where the sprout is erupting from it. I take a small part of the tuber, just a touch along with the sprout.

Some claim you get better results if you have a tiny bit of the mother tuber along with the cutting but I have yet to test that theory. Next I lay the cutting onto my surface and cut away the lower leaves. My knife if pointing to where the leaves were.

I dip the end into my rooting medium, I put some in this little glass. I make sure that the stem is coated up past where the leaves were removed.

Pot Up your Dahlia cuttings

Fill 4 inch pots with moistened potting soil. Use a pencil or dowel to poke a hole down into the potting soil along the edges of the pot, poking the hole wide enough and deep enough that the rooting hormone won’t get rubbed off while slipping it into the soil.

Planting the cuttings along the sides of the pot supposedly helps the roots to break, or run more horizontally instead of straight down

Put about 3 cuttings to a pot and firm them in. They should root in a 2 to 3 weeks. Keep them watered but not soggy. Some put them in an environment to create humidity but I did not bother. See this post for ways I do that..Propagating Geraniums

Pot your Dahlia cuttings up to larger Pots

Once they are growing well move them to their own pots. I do use a bit of bottom heat in my greenhouse as it still gets quite cold at night in there but if you do this in a sunny window of your home you should not need bottom heat. If you scroll back up to the photo of the black planting tray you will note it is sitting on rope lights, that is my cheapo bottom heat. These are not the LED ones, those do not put out heat but the regular ones do put out a gentle heat which works well for me.

The one sprout got chewed on by mice. Who knew they liked the tender growth of Dahlias.

Enjoy your new Dahlias

Even if you take a few cuttings from each tuber it will still grow more and bloom just fine this summer. Just plant it as you normally would once the soil in your garden is warm enough. Dahlias like warm soil, about 60 degrees or so.

So this summer I plan on plenty of Dahlias blooming all around my garden. I will be sure and share how this all comes out in a future post!

And that, my friends, is how you propagate Dahlias from Cuttings.

Happy Gardening!

Video: Propagate Dahlias from Cuttings

More Plant Propagation Posts

Propagate Lavender from Cuttings
Propagate Clematis by Layering
Propagate Lilacs from Cuttings

Taking dahlia cuttings

This is our little dahlia nursey and what you’ll see is I haven’t planted these where the tuber is completely submerged in compost. They’re actually poking out a little bit above and that’s for a good reason because it means that when we are propagating from them to make more, we can actually see the tubers. That’s ideal to enable us to take a successful dahlia cutting as it’s a good idea if you can take a little slither of the tuber at the same time – it won’t affect the parent plant. It means that the actual cutting is more likely to root.

If you take a look at the ‘Sam Hopkins’ tuber we have here, we only want three or five shoots to come from one tuber, otherwise they get too jam packed and too congested when you want better air circulation.

I can easily take one or two shoots off without affecting the beauty of the mother plant. With a sharp knife cut away a tiny part of the tuber with the shoot. Using my finger to make the hole for the little cutting, pop them into a pot with some grit mixed in with the compost, to keep the structure of the compost open.

The amazing thing is that the cuttings will get to the same size of the mother plant in one year. They’ll then form tubers to allow storing for the winter.

You’ll notice that I’m putting the cuttings on the outside of the pot and that’s because it will speed up the process slightly with the roots hitting the side of the pot and breaking, causing lateral budding.

Now I’m going to label them and water well over the top (it’s best to keep them watered morning and night) to make sure they don’t dry out because at this stage they are vulnerable to flopping.

Sarah

How to take Dahlia cuttings – more blooms for free

Are you a Dahlia debutante growing Dahlias for the first time this year? Have you grown them before but never tried taking cuttings? Have you got a plant with lots of bushy growth?

If so you could double, triple or even quadruple the number of flowers by taking cuttings.

Each cutting will grow into a strong plant, flowering this season. Each of these, if overwintered correctly, will produce further stems the following spring, for yet more cuttings. The Dahlia really is a gardener’s thrifty plant of choice.

Dahlias root well from cuttings and even beginner gardeners should give it a go. The very first cuttings I ever made were from Dahlias and I admit to being mystified at the magic of propagation but delighted when it worked.

You can read the step by step guide below for full information including how long the cutting will take to root and the optional use of hormone rooting powder.

You can also watch this short video clip that I posted on Youtube. It shows you just how easy it is. Cuttings take just minutes and this approach has always worked for me.

If you want to know more about growing Dahlias please take a look at my Dahlias for debutantes article which gives information on varieties to try, how to grow and how to look after them over the winter.

Step by step guide to taking Dahlia cuttings

Dahlia shoot, just cut from parent plant

  1. When stems reach 7 to 8 cm long, they should make good cuttings. Take a good look at the stems coming from your tuber and choose which stems to cut. You may need to push the compost aside so you can see where the stems emerge from the tubur. Stems that can be severed from the parent with a small amount of tuber intact are the first to try. This is because the growth hormones needed for good root development are concentrated in the tuber.
  2. Take a sharp knife. This can be a gardener’s knife but a kitchen knife will also do. Ideally the knife should be clean and some growers advocate sterilisation through a flame. Hold the chosen stem and push the knife into the tuber and under the stem to cut it away.
  3. If some of the light brown woody tuber comes with the stem, you have a perfect specimen. If not, don’t worry as the stem can still be used but you will need to cut the stem under a leaf node as shown in the first picture below. A leaf node is simple to spot as there is a swelling on the stem from which the leaves emerge. It should root anyway as there is also a concentration of growth hormones in the leaf node. If you want to you could dip the cut stem into some hormone rotting power or gel but this is not essential.
  4. Carefully tear or cut away any lower leaves on the stem and cut the top leaves in half to reduce the amount of surface area through which moisture can be loss.
  5. Fill a pot with compost. Place a pencil into the compost at the edge of the pot to make a hole and put the stem in, gently firming the soil around it. Three cuttings can usually be fitted around the edge of a 9cm pot.
  6. Water the cuttings. They usually root without covering but if you have a propagator (plastic tray with or without bottom heat and with a clear plastic lid) you could use this. You could also try putting clear a plastic bag over the pot, held in place with a rubber band. Both methods reduce the moisture loss from the cutting but have the potential for the cutting to rot if the atmosphere is overly damp – so do not overwater.
  7. Cuttings will take 2-4 weeks to develop roots. Resist the temptation to pull the stem to see if it has taken. You will know when it has worked as the stem will begin to grow new leaves. Alternatively, if you have some, use the see-through pots used by orchid growers, or even the plastic cups from children’s parties (with drainage holes punctured in the bottom) as you can see the roots growing without disturbance.

How-To: Taking Dahlia Cuttings To Build Your Stock

Vices. Everyone’s got them. I don’t smoke. I rarely have more than one drink at a time. I don’t shop for clothes or shoes unless I really need them. But I do consume more dark chocolate than is probably healthy. And I can’t stop myself from buying over-priced dahlia tubers each winter, even when I already have too many tubers stashed in my basement. I really love getting the new introductions each spring, the varieties no one else has yet. But paying eight or more bucks for a tuber is a pricey addiction.

I can justify the expense because I take that one pricey tuber from the supplier and turn it into six or seven plants. The art/science of taking cuttings is a magic trick any good horticulturist has up their sleeve to propagate coveted plant material. Taking dahlia cuttings couldn’t be easier once you know how to do it.

Cuttings are also a great way to increase your stash of a particular favorite variety. This season here at Love ‘n Fresh, we’re culling some of the varieties that aren’t top sellers and beefing up other varieties (like Taboo, Sherwood Peach, and Jason Matthews) that we love and want to have lots of this autumn for the beautiful boatload of weddings we’ve got coming up.

So here’s a handy step-by-step guide for how to take cuttings from dahlia tubers.

We order our new tubers almost exclusively from Swan Island. We pay a little extra to have them shipped to us in early March so we can get the cuttings going in the greenhouse and nicely rooted for planting come mid-May.

To begin, we line black bulb crates with paper and then fill them with moistened ProMix potting soil. Then we unpack the tubers from their shipping box and lay them out so we can see the names, which are stamped on the tubers. We’re very careful to stay organized by creating tags for each cultivar so we can keep cuttings from each cultivar together as we root them and then plant them together in the field so harvesting single-variety bunches is easy and efficient.

For new growers, here’s a little general tip you might not know. Write your plant tags with pencil. It will last much longer than pen, marker, or anything else. Trust me. It seems illogical, but it’s true.

After we’ve got a tag for each tuber/variety written up, we pop the tubers into the potting soil in the crates. Tubers should be placed vertically and the top of their necks should remain out of the soil (you’ll see why a little further down the post). Tubers get packed fairly tight in the crate since they aren’t going to be growing like that long-term. Twenty-five tubers can easily fit into one crate.

Once a crate is full of tubers (and their associated tags), we gently water the crates to settle the soil around the tubers and then place the crates on heat mats set at 70F. This winter, since it was so very cold, we were keeping the thermostat in the greenhouse pretty low. Dahlia tubers do not like to sprout if they feel a chill in the air so we covered the crates with humidity domes to keep the ambient temperature around the tubers a bit warmer. Worked like a charm.

Tubers usually start sprouting about ten days after going on the heat mat. It takes another week or so for the shoots to be large enough to take cuttings. Shoots should have two fully developed leaves and more on the way as well as a stem that’s at least an inch long before taking the cutting.

Now you can see why we leave the necks of the tubers sticking out above the soil level. To take cuttings, you need to be able to cut cleanly right at the base of the cutting where the fresh green growth meets the brown neck of the tuber. If the tuber was fully buried, it would be hard to take a clean cut without possibly damaging the delicate growing point that resides just inside the tuber’s neck. Once that growing point is damaged, the tuber will be far less productive so it’s important to be very careful to not cut into it. But you also don’t want to cut so that there’s still a piece of the green shoot left on the tuber. If you do that, you’ll get branching so that two shoots come out from the green stump, but they will be weaker and take longer to be a good cutting size than if you just make a clean cut in the first place so one strong shoot grew back in its place. Capisce?

Before taking cuttings, prepare a tray (we use 128s) of moist potting soil and make sure there’s enough room on your heating mat to accommodate that tray. Cuttings really need bottom heat to start rooting quickly or they will just turn into mush. You should also have some form of rooting hormone on hand to encourage rooting. We use Dip ‘n Grow because it’s relatively inexpensive and pretty fool-proof. Just add a bit of the concentrate to the included cup and then fill with water to the desired dilution line. Dahlia cuttings are dipped in a 20x dilution for about an eight second count.

Use a pencil to create little holes in the soil in each cell of the tray and place freshly dipped cuttings into these holes. It’s important to create the holes in the soil with a pencil first so that the rooting hormone on the cutting doesn’t get wiped off as the cutting slides into the soil.

Remember to label each cutting so you continue to keep your varities organized for efficient harvest once they’re set out in the field. It’s good to include the date you took the cutting so you can track how long you’ve been waiting for it to develop roots. Sometimes you have to just chuck a cutting if it’s been inactive for several weeks. But we generally only have a handful of cuttings (out of hundreds) that get tossed each spring.

Keep your cuttings on a heat mat until they’ve developed enough roots that when you gently tug on the leaves there is resistance. At that point, you can chose to either leave them in the same tray or pot them up into a larger container to grow on some more. We usually bump ours up to a 72 tray to grow on a bit before going out into the field.
While the cuttings are getting rooted, make sure to never let the tray dry out or else they will wilt so badly they’ll never rebound. It’s also a good idea to keep trays of fresh cuttings in a bit of shade if you can so they don’t transpire too much in hot sun. You can place a humidity dome over them if you want, but sometimes that does more harm than good. Humidity domes create a very hot and humid environment which can lead to rotting in dahlia cuttings unless you are monitoring them very closely. We just make sure to keep trays evenly moist on heat mats and that works really well for us.

Keep taking cuttings from the mother tubers until mid to late April. We usually take five to seven cuttings from each mother tuber. Any more than that and you risk depleting the mother tuber so much that it will not be productive when you plant it out in the field. Depending on conditions, cuttings are usually rooted and actively growing on their own in three weeks. How big you want them to be before planting them out in the field is up to you.
We fertilize both dahlia cuttings and dahlia plants in the field with weekly applications of a mild organic mix of fish emulsion, kelp, and compost tea. This application really helps combat disease and encourages the plants to put on healthy growth quickly.
By taking dahlia cuttings each spring, you can quickly multiply your stash in no time. Each cutting, if grown properly for a full season in the field, will produce several tubers that can be dug up in the fall. Play your cards right and from one expensive tuber in the spring, you can have 40-60 healthy tubers by the fall. Talk about magic!

January 25: Tonight, I pulled out my tubers from last season. I had a small collection of dahlias- a few that I bought from another flower farmer, some from a garden center, and one that I received from a friend as a gift. I kept my tubers (after cleaning and separating them in October) in a clear plastic tub with pine shavings (I don’t think it is wise to keep them in an airtight container, but I was pretty sure mice would get to them otherwise in our old farmhouse. I used the pine shavings to absorb any moisture that might cause mold- it worked pretty well. They were stored under an eve in a window-seat type storage area).

From my initial collection, I have 22 tubers that I *think* may take (yes– it is a small collection!). I prepped two 1020 trays with some older potting soil and some new, richer compost/seed starting mix from Johnny’s Selected Seeds. Each tray has a slotted liner- more for letting moisture out if I need to, than for bottom watering. I plan to water them from the top and only now and again so they don’t dry out. I put about half of my tubers in one tray, with their “eyes” sticking out of the soil. My tubers are grouped by quality– the ones I think have a good chance of sending up shoots… and the ones that might not. I’m hoping this decision will also curb the spread of disease from the weaker-looking tubers to the stronger ones.

I put clear plastic domes over them before I left tonight- it can get really dry here with the warm air from the heater circulating around the plants. I’ll probably take the domes off during the day. According to Dave’s article, I should be able to take cuttings from these tubers each month from February until I plant them out after the last frost.

January 30: Just five days later I noticed some growth at a tuber eye that hadn’t been there on the 25th. In that time, I had tried to make sure that the soil in the tray was not soaking wet, but that some moisture was visible (loose soil on the top dries up, but I can see that the tubers are getting some water below because the rest of the soil looks and feels damp.)

February 5: I checked on my tubers this morning. In the first days of this trial I saw a little growth more growth at the same tuber eye. A few of the other tubers have also begun to show tiny sprouts.

As so many of you have purchased our Dahlia Tubers I thought it would be fun to follow on from ‘Dahlia Planting Instructions‘ with ‘How to take Dahlia Cuttings’

Cuttings

It’s a really great way to multiply your stock when you’re first starting out and only have a few plants and want to increase your stock rapidly and make identical plants.

You’ll need pots 9cm are ideal, bottom trays, potting compost, vermiculite or horticultural grit, clear plastic sandwich bags and a wooden skewer or a propagation until with a domed lid, and plant labels.

  1. Moisten compost mix until it is thoroughly damp, but not dripping wet.
  2. Fill the pots to the top with soil, tapping firmly against the table as you go, so the soil settles and there are no trapped pockets of air.
  3. Get your label ready, you forget very quickly so write them first!
  4. Only take cuttings from healthy plants with no pest or disease damage.
  5. Any cutting must be solid, Dahlia stems are hollow and these will not root. If you cut with a very sharp knife, I use a scalpel and try and get a tiny part of the tuber, I find this really helps to make a successful cutting strike. The area below the leaves has the highest concentration of hormones which will assist strong rooting. It is important to keep the cutting hydrated, many people use a plastic sandwich bag to seal in the moisture, however I find a bucket of water is much easier. If you do take a cutting from a friends garden and use the sandwich bag technique then as soon as you return home drop your cuttings into water for a good soak for a couple of hours.
  6. Reduce the cutting to 5-6cm (2in) tall and remove all but the top pair of leaves.
  7. Always use a dibber or a pencil to make a hole in the compost for your cutting. The cutting must come into contact with the compost for it to root so don’t make it deeper than a couple of centimetres.
  8. Hormone rooting powder can help with successful rooting, dust a small amount on the cutting, for hygiene reasons never dunk cuttings in the container.
  9. Place your cuttings in the pot keeping the leaves above the soil surface.
  10. Water the cutting and place the pot of in a propagator or cover with a clear polythene bag secured with a rubber band. Use a skewer to stop your bag collapsing onto your cuttings
  11. Place cuttings in a constantly warm (not hot) environment, about 65 degrees. The house is ideal and in the spring a heat mat or heated propagator really helps! Watch out you don’t cook your cuttings in a hot greenhouse!
  12. Check cuttings daily and water from underneath when the soil appears dry. The pot will feel light.
  13. Leave your cuttings for 3-4 weeks.
  14. When you see white roots to emerge from the base of the pot, the cutting has taken, don’t be tempted to disturb the cuttings until you see this, I’ve killed off many a cutting by impatience!
  15. As plants grow, they need to be fed and liquid seaweed is ideal for young plants. Do follow the instructions on the product label, always double checking as strength does differ between manufacturers. See my previous post on Feeding and Plant Teas

If you would like to learn more about taking cuttings and other types of propagation we have special practical ‘hands on’ workshops

I’d love to meet you and show you all my tips and tricks first hand

Zoe x

Swan Cottage Flowers provides the finest quality cut flowers for Weddings and Events all over Bedfordshire, Buckinghamshire, Hertfordshire, Northampton, Oxfordshire and London.

We are close to many of the top Wedding Venues such as Stowe House, Waddesdon Manor and Woburn Abbey.

or call Zoe 07702 919 640 for a chat x

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