All my dahlias have done pretty well, though all have been mildewed since Sept. The one I have enjoyed most is Waltzing Matilda. Not hugely prolific but so gorg. I gave away Creme de Cognac earlier in the summer.
Mexican Star (single) has probably give most blooms. I have three pots of them, all about five ft tall. They start flowering earliest - in May/June. The newly opened blooms smell slightly of cocoa. I will be giving them away. A high percentage (maybe 10%) of the blooms are twisted and mutated. You can kind of see the uneveness of the bloom below - most are like that. The blooms are quite small, for the huge space that the plants take and all the greenery. Just not enough bang.
My Bishop of Llanduff and Mexican Star had more or less finished, it seemed so I have taken the foliage down. They might sprout a bit again before the frosts. When the frosts come, I will cover them. Aruna and Matilda still seem happy to keep going, but they started later.
Your Waltzing Matilda looks amazing @Fire. My two potted dahlias are still flowering, probably enjoying the warm and sunny weather so far.
I will keep Nicholas to grow again next year — love the large lotus-shaped flowers, they appear lit from within. The foliage is darkish green and bushy, which sets off the blooms well.
Will be giving away Embassy (ordered Cornel online but was mistakenly sent the tuber for this one instead). While the flowers are nice, I’m not a fan of their magenta pink hue and they’re not as large or as ball-shaped as I had wanted with Cornel. Leaf/stem growth is a bit spindly and mildew prone, but maybe I got a not-too-robust specimen.
It's my first year growing Dahlias so sorry if this is a daft question. Should I be dividing these tubers? They were newly bought and planted this year and I have just dug them up as they had finished flowering and were getting a bit ropey. Some have really filled out and reading online suggests they can get too big which impacts in the flowering. Not sure whether to leave these another year or two or divide them now.
@Emptyheadtime You can split them if you want, to make more plants, but you don't have to.
I would store them in dry earth (in or a box or a bag or similar) in a cool, dry, dark, frost free place. Watch them closely next spring. You will see them put on growing shoots around April/May time and that is the time to split them. You will see various growth eyes or growth point around the tuber - sometimes underneath. If you wait a while, the shooting points will be easier to spot. As long as the section you create (cut) has one green shoot or sprig it should be fine to pot up. Be careful in splitting as the shoots can snap off quite easily. Don't water it as it may rot off. Wait for some green top growth before watering.  Below are not my pics.
I personally found that when I split tubers, that the plants were noticably smaller with less flowers that year (grown in pots). But I see dahlia farmers swear it makes no difference to the floriferousness of the plant. If keen, I guess you try splitting one or two plants and see what happens for you.
There are loads of different ways of spitting tubers. Above is just the way I have used and it works for me.
I thought I had lost some to the drought this summer, they are currently re sprouting and look like lovely lush early summer growth. I worry that this crazy warm dry weather here in Paris has got them confused. Spring bulbs arrête all starting to pop up as well.
I cut back some of my Bish of Llanduff dahlias back at the end of Sept and they have resprouted beautifully - fresh, unmarked growth, building the tuber.
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I will keep Nicholas to grow again next year — love the large lotus-shaped flowers, they appear lit from within. The foliage is darkish green and bushy, which sets off the blooms well.
They were newly bought and planted this year and I have just dug them up as they had finished flowering and were getting a bit ropey. Some have really filled out and reading online suggests they can get too big which impacts in the flowering. Not sure whether to leave these another year or two or divide them now.