Growing Dahlias: Trimming and Staking
This Post May Contain Affiliate Links. Please Read Our Disclosure Policy
This is an exciting day! I’m here with an update on my adventure in growing dahlias! Today I’m going to show you how my 27 tubers are doing and let you know what’s next for the dahlias I’m growing.
Growing Dahlias: Trimming and Staking
As I mentioned in my first post in this series, I’m a novice at growing dahlias. This is my first official year growing dahlias in my backyard garden. (Last year I put a few tubers in pots, but I’m not sure that counts.)
I planted 27 tubers (details on the varieties can be found here) this year, and I’m happy to report that all of them have sprouted!
To be more precise, 25 sprouted, and I needed to plant 2 additional tubers. So technically speaking, 27 of the 29 tubers I planted are growing. Not too shabby for a newbie dahlia gardener!
Here’s a peek at how my garden looks right now:
Not bad, right? As you can see, there is some variance in the height and growth of the plants. That’s because different varieties of tubers have different germination times. I noticed that the varieties I planted needed from 2 to 5 weeks to germinate.
Once everything is growing, it’s time to do a couple of things. The first is staking; the second is trimming or pinching.
Growing Dahlias: Staking
Dahlias grow tall and have large blooms. Thus, they need support as they grow. I decided to use cedar stakes and garden twine (both from Lowes) to support my dahlias.
It’s important not to damage your tubers when adding the stakes. The best way is to insert the stakes in the soil before planting your tubers.
Since I didn’t do this, I had to wait to put in my stakes until after all of my tubers had started to bloom. That way I knew exactly where each tuber was planted.
For my 27 dahlia plants, I used 18 cedar stakes. I then took garden twine and created a grid between all of the stakes. To avoid damaging the plants, a soft rope or garden twine is best. (This twine is similar to mine.)
As you can see in the photos, I created two rows (or levels) of twine. This will offer twice the support as my dahlias grow.
Although I think my grid will be sufficient, I might create extra support by running garden twine diagonally between the stakes. Again, I’m new to all of this, so if you have suggestions, please let me know.
Other Staking methods:
From my research (and my limited personal experience), I’ve learned there are other staking methods to consider.
- Cage/Trellis – Last year, I planted my tubers in large terra cotta pots. For support, I added a cage to each pot. (I found mine at Lowes, but these are similar.) The cages provided excellent support.
- Grid System – You can also purchase a grid system like this one to support your blooms.
- Single Stake – Another option is to put a stake next to each dahlia once it gets large enough. You can use garden twine to attach the plant to the stake.
I hope these additional ideas are helpful.
Okay, now that your dahlias have been properly staked, it’s time to talk about trimming.
Growing Dahlias: Trimming
It doesn’t matter who I consult or what I read, everyone recommends trimming or pinching dahlias in the early stages of their growth.
It seems counterproductive to cut the top off the plant, but doing so encourages branching, which will give you a fuller plant and more flowers! That’s the goal, of course!
And don’t worry. At this point in the dahlias’ life cycle, they are sprouting and growing rapidly, so they will recover quickly.
When to Trim Dahlias?
You want to trim off the top of the dahlia when the plant is about 16 to 18 inches tall. There should be at least four sets of leaves by then. Pinch or cut the center growing tip right above the fourth set of leaves.
It’s that simple. Again, this will help you create a stronger plant with more blooms. It can keep the plant from becoming top-heavy. Win-win!
And that’s it! All that’s left is for the plants to grow and bloom.
Growing Dahlias: More to Come!
If you’re wondering about fertilizing and pest control, I will discuss that in my next growing dahlias post. I’m still testing different methods and products. I promise to share what I learn.
Once I have a few blooms, I’ll also offer information on cutting, deadheading, and such. But I can tell you now that the more blooms you cut, the more the plants will grow. Which is another reason to love dahlias!
In case you have any questions, please let me know in the comments below!
I hope you find this series of posts helpful should you decide to also grow dahlias. For me, this adventure has been filled with much joy and learning. I can’t recommend it enough.
Here’s to LOTS of beautiful blooms!
Hello,
Love your post and photos! This is my first time growing dahlia in my raised bed. I think I should have pruned earlier, but too late now. It is late July and they are now about 2-3 feet in height. Can I still prune? How and where? Central stem and how low? I’m in Southern California. Climate is in the mid to high 70’s at the moment. Would love to keep them going into the Fall. What do you suggest. I have not fertilized either. Would love your input.
Thank you,
Stephanie
Thank you for sharing all of this! I am planning my (first) dahlia garden and am planning to do pretty much the same thing you have described. I wanted to ask, did this spacing work out ok? I W]was planning 12 in. spacing as well, but sometimes get nervous that that may be too close? Would love to hear how yours turned out!! Any tips or things learned for next year?
Thank you for these posts!
Thank you for all you share. I am for now living in an apartment in downtown San Diego. June gloom hanging around giving me about three hours of the sunshine a day. I am vicariously living through your blog!!!!
Your garden looks to be in a shady spot. How much sunshine is needed?
Beautiful garden.
Miss seeing you Michael. Love the garden and the red chair!
I have been growing dailies for 20 years. After cleaning and drying the tubers for
Several weeks, I store them in brown paper paper bags in a cool place in my basement.
This year I planted 40 in different flower beds. I started with 1 plant and they have
Multiplied over the years. Each year I share with family and friends.
My favourites are fuchia coloured which get about 4 feet tall and flower
Robustly. After 18 years my pink dinnerplate dahlias did not survive. They
Are all staked with bamboo poles. My red, white and yellow grow about
2 feet or so.
My garden contains many varieties of flowering bushes and perennials which
Gives colour all season. Each one blooming for a period of a month. Nothing
Beats the dahlias which bloom from early July until frost gets them approximately
The 15 Oct.
Living in Canada where the spring can be very cold, I start my tubers at the end
Of April in pots in my garage. I plant them in the flower beds 1st week of June.
The extra work is well worth the results. Beautiful cut flowers to give as gifts
And fill your home.
Black aphids can be a problem on the newest shoots and flower buds. I just remove them with my fingers. A bit messy but very effective and quick. Earwigs can also damage flowers. The old fashioned method of control is to place upended flower pots on stakes at the same height as the flowers. Stuff the pots with straw. Every day inspect the pots and squash the earwigs. Both suggestions are environmentally friendly and satisfying!!
What a great discussion. I am growing dahlias in a raised bed too so all of these tips are quite helpful.
Hi, I’m in the U.K. and for the first time ever I have planted 5 dahlia tubers in a large wooden trough. They started to grow beautifully but something has totally destroyed one and is now munching it’s way through the rest…. I cannot see any slugs or snails but how can I deter them &/or protect my plants, please?
Very enjoyable and great suggestions. I have several tubers that I had stored in brown paper bags in the mud room. 1 dahlia is in its 2nd year called Daria in Love which each bloom is different. They are completely maroon, some with a few pink petals with the maroon and some maroon on the edge and pink petals in the center. Would love to share pictures.
Hi liked the information you , sir am from India and I have planted dahlias in pot since the last since there are no blooms at all although the plant is tall and green .
Do they really like full sun? Mine droop a lot on hot days even though watered. Thank you
From what I’ve read they require at least 8 hours of direct sunlight. They are native to Mexico and Central America, so I assume they would love the heat and sun.
xo Michael
Yes, full sun. And they will droop a bit on hot days, keep them watered, from underneath the leaves. Water the stem area by the soil, not overhead. And keep them staked and supported, enjoy
I’m growing dahlias for the first time this year so this just popped up in my google news feed. I’m growing 10 varieties, 8 of which have sprouted already! I’m glad to read about trimming them back because quite frankly, I didn’t read much beyond how to plant them, heh. So thanks for this.
Some what new, I got a few tubers from a friend 3 years ago so started growing Dahlias. I do pinch/ deadhead flowers but never trimmed at 16″.. I use 6ft.Bamboo stakes from HD. Get them in ground solidly when they’re about foot tall
Planted tubers on mothers
day and its Fathers day now and got my first flower of season and alot of big buds.
Ready to burst.
In late fall I pulled and washed and air dryer them for a few weeks and stored in old coffee can ( plastic) in cool basement and some made it but alot got that white mold and turned soft & got mold so order a few new tubers. I got 1 or 2 much larger plants so I’m thinking I didn’t pull them out, i must have missed and because of the mild winter in mid Atlantic states they survived and didn’t get frozen.
I guess that is the tricky part is storing them over in the winter. That would be most helpful info.
Enjoy the great show when they are all blooming.
I stored mine in a large plastic tub and put sponge inside to keep tubers warm (haha) same as fuschias and kept in greenhouse. All survived ready for new season.
Its the end of June and dahlias are well beyond four leaves . Am I able to still trim as you suggested?
I believe so! It may take a little longer to bloom, but you should get more blooms. Feel free to do more research though. I’m just learning myself.
xo Michael
Yes,go ahead you’ll be fine! I’ve got over 100 tuber sets, and have been growing (and loving) dahlias for many years. Enjoy
I need to know what to do with dahlia bugs,there is something eating my dalias right of the top .thanks.
Depends on what the bugs are.. there are no bugs dedicated to dahlias. I’ve found japanese beetles, earwigs, slugs and various caterpillars on mine thought the season. Not often tho. Slugs are usually the culprits. Slug bait and picking off beetles into soapy water it’s about all I do. And keeping an eye on them to pick off any others.
So exciting! Thanks for this info, it’s very helpful! Quick question! What is your garden arch made of? And where can I get my hands on some?!
Thank you!! It’s hog wire from Tractor Supply. I zip-tied it to t-posts which were also from Tractor Supply.
xo Michael
I’m growing several dahlias this year as well! I have discovered a wonderful UK gardener (Zoe )with a great Instagram account that’s very educational! Her husband, Neal, has designed a great “frame” for growing dahlias and any other tall flower varieties. Could be a great project for next year 🙂
https://swancottageflowers.co.uk/2019/01/25/our-flower-growing-frames/
I hope you get to spend lots of relaxing hours in your garden. What a lovely, peaceful place!