How to Split Dahlia Tubers.

If you’re lucky you live in an area where you don’t have to dig up your Dahlia tubers.  For the rest of us we must dig, divide and conquer.  How to split  Dahlia tubers to keep ’em growing.  (even if you live in an area where you don’t have to dig them up you *should* still split your tubers)

Try as I might, despite all of my efforts, I could not kill my dahlia tubers over the winter. I stored them improperly, ignored them and silently cursed them.  I’d have given them the evil eye if I believed in that sort of thing but I don’t, so I stuck with a garden variety exorcism.

No luck.

At the beginning of April I opened up my plastic bags of Dahlia tubers expecting to find a wrinkled mass of nothing and found perfectly fine tubers.

I bought and planted these tubers (a LOT of them) for the first time last summer.  You can see the mountain of Dahlias 10 or so tubers produced in this post.  In the fall, because I live in a cold climate, I dug them up and stored the mammoth things.  After one summer in the garden the tubers went from the size of a cute little baby finger to something you could revolve an entire a horror movie around.

I dumped out all the tubers and started looking around the house for containers big enough to plant these Stephen King characters in.  It took a while for me to realize that this just couldn’t be how it was done. No one I know who grows Dahlias ever mentioned the need keep 10 or 20 igloo sized pots around for planting the tubers in, in the spring.  I must have to DO something with these tubers before planting them again.

Sure enough – I had to split the tubers.  And so I did.  Some quick research online led me to understand how and when to spit the tubers so now I’ll tell you what I learned.

Clearly I’m not an expert.  But the gist of it just involves cutting each finger off and making sure there is at least 1 eye on each of them.  If you want a more finessed explanation you’ll have to do your own Googling.

How to Split Dahlia Tubers

 

 

STEPS

1. Remove the stringy, withered tubers that will never amount to anything.

 

See? That’s not going to do anything for you.

 

2. Once you get all the extraneous stuff trimmed away you can better see what you’re working with.

3.  Dahlias sprout from eyes on the very top of the tuber necks.  So start cutting off each tuber, making sure to include enough of the neck that you get some eyes.

4.  If there are any tubers growing off of other tubers, cut those off and throw them away.  Those piggy back tubers will never produce Dahlias.  The big main one will, just not its parasitic twin.

If you’re lucky, your Dahlia will have already started to sprout which makes spotting the eyes easy.  They’ll have a stem coming out of them.  Or they’ll be swollen enough that you can spot them like in the photo below.

For any tubers that didn’t have an obvious eye, I just cut them, taking plenty of neck and hoped for the best.

I told you I wasn’t some sort of Dahlia expert, right?  Like, we’ve established that haven’t we?  ‘Cause I don’t want you to think I’m posing as some sort of Dahlia expert.  Really I’m just a girl with a pair of clippers.

 

Once you’ve decimated the horror show of tubers,  you’ll have several individual, viable tubers for planting this year – all out of that one tuber from last year.  This compounds year after year until eventually you  have enough Dahlias to start your own free love hippie compound.

Dahlias can seem overwhelming because they do need a bit of work what with having to dig them up, hex them, and replant them every season. They demand attention, you can’t just plant them and forget them.  Don’t let their bossiness stop you from growing them though.  Divide … and conquer your Dahlias.

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26 Comments

  1. Tina says:

    I have a friend whom I have found to be the Dahlia King of Oregon. I am always amazed at how many acres he gets of these massive flowers! This year I bought a few, I plan on challenging y’all in a couple of years!

  2. Paula says:

    You are right – that size wouldn’t do anything for me.

  3. Jenny W says:

    I think I need you to draw an arrow pointing to the eye, cause both ends look the same to me :/

  4. danni says:

    I had been eyeballing dahlia tubers at the local mega hardware store but managed to control myself until that last post about them. Now we will see just how bad/good it gets. ….
    I’m a sucker for overachievers. Which omg now that I think of it the damn luffa vine was last year! Oh what have I done!?!?
    (Karen, if my mom were alive she would not be letting me hang with you! Bad influence!)
    (Pffft, like that would deter me!)

    • Karen says:

      That’s me! Terrible influence. 😉 My luffa plants are HUGE, ready and waiting to be transplanted in the next few weeks. Maybe I’ll plant them near the dahlias and watch them fight over territory all summer. ~ karen!

  5. Kathryn says:

    I’m picking up a bag of Dahlia tubers from a friend who has too many at lunch today. Now I see what I’ve signed up for.

  6. Ev Wilcox says:

    NO NO NO NO NO! I am struggling enough with all the daffodils that need separating. You guys just go on, have fun, blah blah blah, etc.! thanks anyway Karen!

  7. Susan Claire says:

    I bought dahlia tubers one year, planted them, waited in vain for beautiful flowers, and then realized that I had just supplied the gophers with some very expensive appetizers.

  8. Marilyn says:

    I just bought two at a garage sale ! Hoping for the best..

  9. Sabina says:

    My mom always had the green thumb for dahlia’s, I’m embarrassed to say I’m intimidated by the whole digging up and storing task. They’re just so beautiful though. I’m wondering how they’d do in a big planter and then rolled into the garage in the winter…

  10. Elizabeth says:

    Well this is timely. I just pulled out my probably-not-stored-correctly-tubers out of the cupboard just this morning. I was surprised to see an inch long green growth coming out of one of them.

    This is my first over winter storage and my first replanting. Crossing my fingers.

    Now off to find out what to do with my grapevines and hoping I am not too late do have done something by now.

  11. Sharon says:

    I’m a fan of dahlias, except the staking, digging, and storing part. I never got the knack of staking them attractively. They always seemed to sprawl. How do you stake them? I left mine in the ground thinking they would die, but despite some very cold winter days, they are coming up and begging to be taken care of.

    • Karen says:

      Hi, Sharon
      We use tomato cages to stake our dahlias in Oregon. :o)
      blessings on your day!

    • Karen says:

      Because these were for cutting and not in a “pretty garden” I didn’t stake them at all, lol. I just let them do their thing which is risky because they break easily. They did fine though. My guess is one of those rings that normally go around Peonies would be a good thing to use for Dahlias. ~ karen!

  12. Emily says:

    Where did you store the tubers during the winter? I don’t have a garage so the basement would be my only option.

  13. Julie says:

    If dividing your tubers seems too complicated, you can just dig a hole and plant the whole big withered thing! It works fine for a few years! Then you can just hack the clump in two…no need to make it too complicated! Of course if you want to have an acre of dahlias, you would probably need to carefully divide the tubers!

  14. Christine says:

    Hi Karen,
    Do you plant your dahlias in a lot of sun? Also do you put anything special in the planting hole?
    I grew dahlias last year. We live in Minnesota so I dug them up last fall and, of course, the tubers rotted out and became moldy over the winter. So I ordered some more this year and they just arrived.
    I did not get a lot of flowers on them last year so I’m wondering what is your secret!

    • Karen says:

      Hi Christine. Yes, full sun. I never do anything special with any vegetables or flowers other than laying compost onto the soil before planting. 1-2″. Don’t dig your tubers up until the leaves have gone brown and dead looking. Also cut them! The more you cut the more they grow. For bigger blooms you can pinch them. Dahlias grow with 3 shoots per stem. Two side flowers and one centre flower (which will always be the largest). Pinch off the two side shoots for a big flower and to encourage more flowering. ~ karen!

    • PK says:

      Christine,dry them in a bowl or box of peat moss to take away moisture and prevent rotting.Many tubers are actually sold this way.

  15. ~Renae says:

    Dahlias are the zucchini of the flower world, so much bang for the buck! I do find them to be a little terrifying though…the earwigs love to hide in them. God, I hate earwigs.

  16. Anne says:

    I love dahlias. I’ve got some that I’ve had for years and a few others that I couldn’t resist at plant sales or someone’s given me. I put mine in boxes, no covers, and put them in our not-very-big pump house. If we get a cold spell in the winter, we put a light bulb in there and it seems to be just enough to get them through. I plant almost every little bit that looks like it might grow, lots I start in pots, and those that I end up not having room for, go on the side of the road for anyone who wants them.

  17. PK says:

    I started with ten tubers.I now have plants with 50 tubers every year.I am at the point where I should dig every fall but I don’t dig them all up.I cut them back and dig and separate different ones each year. I replant the same day.I dry some over the winter but normally just plant and throw grass mulch on top.I’m on West Coast of Canada. Snow is very rare here and ground stays warm enough.Most of the tubers i dry,I give away.I could not begin to find places to plant them all them.many of mine are (were) 8 ft. until my wife murdered them.Beautiful flowers but they do need work.Water from the bottom as the Flowers don’t like water. It is now August and I’ve watered my large plants about 5 times since June. You can’t kill them

    • Karen says:

      I killed some! This summer, up at my cutting garden I water automatically and what was great for the vegetables ended up being WAY too much water for the dahlias and a lot of them rotted. :/ Luckily the ones I planted at home grew huge so I’ll still have a billion tubers for storage. ~ karen!

  18. katie says:

    dug mine up this year cant make head nor tail of them. but i know a little now from the posts.
    is it ok to plant in large planter because i would have to keep moving it to get enough sun i live in ireland no way would we get 8 hours of sunshine every day, we are lucky to get that in a year (joke). great to get all the tips

    • Karen says:

      Hi Katie! I’ve never done it but I don’t see any reason why you couldn’t grow the dahlia in a pot! Just make sure it’s large enough. That tiny little tuber turns into a great big tuber by the end of the season. And make sure the soil has plenty of compost and/or fertilizer so it has enough to feed on through the season. Then replenish the nutrients every year. ~ karen!

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