Dahlia tubers ...urgent help needed

[Jeannine]

The lovely lottie man opposite me has had to give up due to very poor health.He has sent me his Dahlia tubers, there are several extremely large clumps,they have been in the greenhouse over the winter.I have no idea what to do with them. I used to love his show of wonderful dahlias so he used to cut bunches for me.

Can someone please tell me what I do with them as I feel they should be in the ground,I was only sent them a few days ago.

I know diddly about dahlias,absolutely nothing.

XX Jeannine

[Jeannine]

[glow777]

definately shouldny be in the ground as they are not frost hardy.

The old bloke next to me puts his in pots (not much bigger than the root) in his greenhouse and waits for them to sprout - then plants out after last frost

[Columbus]

Hi Jean, Hi all  :)

Because I have difficulty over-wintering tubers I left them in the ground this year and they have survived and are now coming through. I stored some new ones in leaf mould in wooden boxes in the greenhouse and they also grew so I planted them out and they are also fine. I have tried to protect plants individually with bell-type cloches (pop bottles and similar) but they are detirmined to grow.

I would plant the tubers into large tubs if you can in a protected space and wait till they start to sprout but don`t leave them sitting about to dry out or rot.

Col

[froglets]

Another us for those black buckets we all collect!

Get the tubers into compost & sit in a sheltered spot.  Make sure the pots can't get sodden if it rains, and speak to them nicely.  Should do the job.

[Jeannine]

These are far too big for black buckets, the clumps are huge, probably 20 inches accross,no kidding. They would have to go in the ground but when, how deep, etc and how do I look after them please. XX Jeannine

[Slug_killer]

For looking after tubers,  have a look at :-


http://www.allotments4all.co.uk/joomla/component/option,com_smf/Itemid,91/topic,28501.0
http://www.allotments4all.co.uk/joomla/component/option,com_smf/Itemid,91/topic,28522.0


As for propagation from tubers/dividing a clump :-

Large tuber clumps can be divided either in the autumn or the spring. When dividing, each piece needs to have an eye. The eyes are located near the old stem of the clump. Eyes are easier to locate in the spring, but large clumps take up more over wintering space and are more likely to rot. All cuts should be dusted with yellow sulphur to prevent rotting.

The best flowers come from one or two year old tubers. Exhibitors use basal cuttings and chuck the tuber.

I would certainly recommend dividing up a 20" clump. The best bits will be around the edge. The middle is probably just pith and dead tuber, as this was the original plant.
I try not to cut tubers, but use my hands and brute force as this means they break at the natural weekest point. However I usually have a bread knife handy.



As for looking after them ... the following is part of a Fact Sheet I wrote for a local garden centre ... Are you sitting comfortably ?




7. Cultivation

Planting

Most Dahlias are planted as tubers from late spring to early summer, once all chance of frost has gone. The exact time depends on when the plant is needed to flower; it takes between 70 and 140 days from planting to flowering, depending on variety. For exhibitors, the timing of planting to co-ordinate with show schedules is a fine art. For the gardener, spreading the planting over a period of several weeks will lengthen the flowering period.

Tubers should be planted about 10cm (3-4 inches) deep, and 30-60cm (12-24 inches) apart, depending on expected size. If dahlias are planted too close together, they will compete for sun and water, resulting in disappointing flowers.

Seeds can also be sown, from February onwards. Germination is straight forward, a propagator on a sunny windowsill is adequate. Young plants should be hardened-off and planted out in early summer.


Care during the growing period

Once growth is under way, a handful of a balanced fertiliser and a good watering is all the dahlia needs for strong growth.

As the dahlia is a tall herbaceous plant, it has trouble supporting itself, especially in wind; thus it is always advisable to stake plants.

As mentioned above, the dahlia is a thirsty plant and needs 25mm (1 inch) of water a week. This should be applied as directly to the roots as possible. Watering the leaves in hot weather just causes scorching.


Stopping, Flowering and Feeding

Once the plant has grown to the required height, it should be ‘stopped’, ie the growing tip should be removed. This will reduce the natural apical dominance and encourage the plant to produce side shoots from the buds in the leaf axils. More shoots means more flowers. The exhibitor can also use this to control the flowering times. A flower head that is less than 20cm (8inches) across (ie a ‘medium’ classification or less), it takes 8 weeks from stopping to flowering, longer for larger blooms. At this stage, a high potash feed should be applied.

As the plant starts to produce flower buds, the exhibitor will remove all wing buds (side buds), just leaving the main crown bud. At the same time the lower third of leaves should be removed. This reduces overall water usage and allows the shoot to concentrate on a single, and much larger, flower head.
The gardener may wish to leave all wing buds on to increase the number of flower heads, but they will be reduced in size.

Dead heading

As the season progresses, flower heads will come and go. Removing the old ones has the same effect disbudding, in that it reduces apical dominance Hence more shoots will be produced and therefore more flower heads
This will continue right into November, when the day length shortens to less than 10 hours and sun strength and temperatures drop.


Lifting and Storing Tubers

Lifting tubers should be done about 2 weeks after a killing frost, the plants will turn brown if frosted hard enough. Tubers dug too early are still "green" and will not store. Cut the stalk off to about 6", gently lift tubers with a spade or fork carefully so as not to break the necks. Wash dirt from the roots and allow to air dry. Tubers with large stems should be hung upside down to prevent water collecting at the plant base, and rotting the tuber.

Once dry, tubers should be trimmed, any root less than the thickness of a pencil should be removed.

Tubers should be stored in crates or cardboard boxes. Containers lined with 10-12 sheets of newspaper are best. Never store in sealed plastic bags or plastic containers. Tubers should be packed in a storage medium such as slightly dampened peat, sand, or straw.

Store in a cool, dry area (temp. of 40-50 F, 70% humidity). Too warm they will wrinkle/shrivel and too cold they will freeze/rot. Tubers should be checked once a month throughout the winter months.



Hope that helps.

[Jeannine]

Wow, that is super info. I will print that off. I am scared about the dividing bit though. The man that has these loved his dahlias and I feel very honoured to be given these  so I must try my best. I will have a look later today to see if I can see it's eyes. Really nervous though. Thank you XX Jeannine

[Common_Clay]

Hi Jeannine,

                     Good luck with your dahlias, I've somehow managed to acquire around 40 tubers over the years and have been getting them in the ground in the last few weeks. The tubers should be planted 6 weeks BEFORE the last frost. That comes from Dobies. They can start flowering from June, so need to go in. They also flowered last year until October-November!
  Can we have some pics once they're in bloom, please?

   :)

[Jeannine]

Could I jsdu dig a big hole nad put them in as they are for this year I am really scared about breaking them up

[Common_Clay]

I'm no expert but I'd say so, if you don't mind digging graves!  ;) :)

[Jeannine]

Ok. one more qwuestion please, how deep. For eg how much soil should be over the top of the clump XX Jeannine

[Slug_killer]

Planting

The bulk of the tuber should be 3" to 4" deep, just leaving the tip of last years stem just poking through the soil/compost. Yes you can plant a whole clump, but its not the best thing to do.
I would recommend splitting at least one of your 'several' tubers either with a knife, or by hand. Go on - be brave - I've been doing it for years, if you don't try you'll never know how simple and easy it is.

If you don't divide, and a large clump rots next winter, where will you be then - take out an insurance policy and divide now.



Propagation by division.

Are there any shoots starting to show yet?

If not, plant as above in a temporary tub and water well. If possible provide some bottom heat, otherwise place in the warmest, sunniest place you can find. (Shouldn't be too difficult at the moment). BUT make sure it doesn't dry out, and you MUST avoid frosts and slugs.  (The forcast says possible dawn frost next weekend (May 6/7/8).

Within a week to 10 days, there should be little shoots forming around last years stems - you might have to dig around to find them.

Once sprouting, it is far easier to assess how to divide a large tuber. Divide the tuber up so that there is at least one shoot in each division. In your case, as your a little unsure, I suggest dividing up so that there are 3 or 4 shoots per division. These can be "chicken legs", ie one fat tuberous root with a small piece of last years shoot on and a few new shoots, or, a whole clump/collection of tuberous roots.

For extra protection, although not really necessarily on healthy roots, dust any ropt/cuts with Yellow or Green Sulphur.
Also cut away any sections that are squishy as these are rotting and the rot WILL spread.
Don't be worried if a few bits drop off - they always do - especially when using a knife. And don't worry if you damage any young shoots, as they'll probably sprout again from the same spot - but best to be carfull not to damage too many.


Be brave and good luck.

[Slug_killer]

If your still unsure about dividing clumps, go to any shows nearby and seek out the old blokes cowering in the corner. Chances are that they've grown dahlias.

But the planting season is nearly over, so don't delay, or you'll have a disappointing display.



Oh, don't know if you already know, but dahlias make ideal slug food, keep them at bay !