Kenora Clyde, Formby Kaitlyn, HH Big Pink, HH Letitia, our new best 2022 WL seedling, all have tendency to sprout oversized cuttings. Some varieties go the other way and go from normal sized sprouts to very small but numerous sprouts. Rooting 1.5 to 2 inch skinny cuttings works well enough but the plants will be a week or more behind to catch up in size. I am going to increase my liquid fertilizer amounts and kick start them after they are rooted. Wait a second: where are all of the rooted cuttings going to grow bigger as the large green house is still a refrigerator and I need to clean out my 8x12 small greenhouse that is heated. Another task for the day: clean out small greenhouse.
Chilson's Pride was the most successful cut flower of all time. Picture by Karen Bull, We are taking cuttings of our version of a "look alike". I took one really nice picture of our seedling. God only knows where that picture is. At least I have about 6 cuttings of it but showing you a picture of the rooted cutting is not going to impress anybody.
Taking Dahlia Cuttings
That is an interesting idea, Ted...a look like for Chilson's Pride. What does your seedling do that Chilson's doesn't? I have to admit I went to some length to kill Chilson's Pride because it was trying to take over my garden and my life. When one plant puts out over 100 flowers at a picking before long no one will buy them. Actually, I do like pink and your seedling is very pretty. And hopefully it does not fimbriate when the weather turns warm....
Our Chilson's Look alike is seedling of HH Mothers Day and I am hoping it too is a 7 footer with wooden stalks and stiff stems like Mother's Day. Light pink sounds easy to breed but they are not all that easy. I consider the picture of Chilsons Pride by Karen Bull above to be the best one I have seen but it is not really representative of how it looks in most gardens as the color fades a bit and the ends of the florets get obnoxious splits.
I've been reading the cubits files on cuttings, and it's noted that leaf cuttings require starting with a dahlia plant that is 12 to 18 inches tall. I'm wondering why the plant needs to be this tall and why, for example, one couldn't take two leaf cuttings by splitting these two pictured.
Oh! Is it because the axillary bud is a crucial part of the rooting process, and they haven't formed yet on this sized sprout?
I just got done taking 21 cuttings from a coleus plant. It had lots of branches and each branch contributed several cuttings. Dahlias seldom have as many branches and the plant in your picture would only yield thee cutting:s two leaf cuttings and a tip cutting. Since you grew it this big , bigger yet would be better.
Teddahlia Ah ok! I just took the one tuber-sprout cutting from this one to have a back-up pot tuber this year, but now I see why it makes more sense to wait for 12-18 inches for leaf cuttings! Higher yield, assuming one is proficient in taking leaf cuttings. I’ll wait to try them for the first time until I have a large enough sprout from a variety I have more of to experiment with. Thank you so much!
I have reached the time when I no longer take cuttings from numerous varieties and move those pot tubers out of our work area. Lots of others are still producing and some late arrivals have not yielded the first cutting. Rooting has been normal this year with about 25 out of 36 having roots after 12 days. Usually at least one shrivels up and dies and the others that do not yet have roots are moved to the root cutting "hospital" where they will get more time to root. There are always some of those overly thick cuttings that never root and I let them try for over month before tossing them. Reasons for not rooting:
Operator error: plant not inserted into pot properly(snugly), plant had broken stem from overly vigorous removal, placing plant on the end of the flat where sometimes there is some condensation, cutting is from a very expensive tuber and you are unlucky, not all leaf cuttings root.
Not operator error: unknown(bad luck), black leg, rotten stems and the poor storing varieties have many more rooting issues.
Some flats have 100% success each year, where all are rooted and none rotted. One came close this year.
Only two cuttings of this one so far and that is disappointing.
Teddahlia Since you’re rooting in pots, what is the easiest/gentlest way to confirm whether a cutting has rooted? I’m thinking a little cutting could last quite a while looking perky, without roots as long as they’re receiving enough water via the cut-end and humidity is high enough. Also, who’s this beauty pictured, what a babe!
My 2.5x2.125x2.5 inch pots have 4 weep holes at the corners . Rooted cuttings will have white roots coming out of the weep holes. If the plant looks rooted, you can water it(helps when taking it out of the pot) and pop it out and most of the time you can see the white roots. If you still do not see roots, you remove the soil from the cutting and look at it and most times it has .25 inch long roots that will root just fine. Finally, no roots at all and you may have a dud. I only go through this process if I have exceptional curiosity. Patience may well be a virtue.
Teddahlia Oh ok this is great, I used 3.5x4” pots so I’ll just assume they’re doing their thing if they look good after 14 days in the bag and find out what happens. By nature I’m, unfortunately, exceptionally curious but I’ll try to practice patience and just trust the process. Since you’re starting yours in 2.5x2.125x2.5 inch pots, do you just up-pot when you begin to see roots coming out of the weep holes?
The magic in rooting in these small pots is that they are never transplanted to another pot and they just go into the ground when they are large enough plants. . With most all the other rooting procedures there is at least one move to another pot. They do get a bit root bound and grow bit tall but it has worked rather well for us over the last 20 years or so. If a cutting is being saved as pot tuber it is transplanted to a 4, or 5 or 6 or 7 inch pot. Mostly 4 inch pots for pot tubers. Halls of Heddon in the UK grow their pot tubers in 3 inch pots and I tried them without success. I have a couple hundred 3 inch pots I will never use that I need to give away. Halls of Heddon grow their pot tubers in the green house with automated watering and fertilizer and probably shade cloth when required. My outdoor growing area does not work with 3 inch pots although HH Black Beauty made some nice little pot tubers. 
Teddahlia Oh wow, how beautifully simple to skip the up potting step! What is it about the small-sized pots that cause them to grow taller? Or is this happening when/because they’re all crammed so close together in a tray together? Do the tubers eventually break out of the pot during the grow season, underground?
Is it common for cuttings that have been rooted and moved to a 4" pot to have the bottom leaves dry up? If not, what should be done to prevent this?
"...bottom leaves dry up." Bottom leaves are the oldest on the plant and often die. Many show gardeners always remove them. I do not, too much work and it causes the plants to grow taller and our plants are tall enough. At a trial garden they removed the bottom leaves from one of our entries and then again. and maybe third time.(fungus?) The plants were 11 feet tall and could not be judged as the flowers were too high on the plants.
I have a question about fertilizing cuttings. @Teddahlia has mentioned using a diluted mix of Jack's 20/20/20, which I found at my local place. Is this for the cuttings after they have roots? I seem to recall you suggested also giving it to the tubers that are providing the cuttings. Is that correct? I wonder if I was too stingy with water on those tubers.
Mine seem kind of slow--it's taking me a lot longer than I'd read to get sprouts and roots and growth. Though now they do seem to be picking up speed. Oddly, it's the most stubborn plant from last season that is giving me the best material. Orange Globe was fussy in storage, except for one beautiful tuber that I've been babying in hopes that I can try this one again. The blooms were gorgeous, but she was slow and short. It was practically impossible to purchase this year, so I really want to succeed with the cuttings.
Thanks in advance!