Posts Tagged ‘Dahlias’

Putting the Dahlias to bed

The relatively warm weather through November and the start of December has meant that the Dahlias have kept going longer than might otherwise have been expected; the first frost was only experienced at the end of the first week of December, the Dahlias blackening under the touch of icy fingers.

Dahlia after the frost

Dahlia tubers will continue to grow until the first frost, after which the choice is either to lift or to mulch.  This year we will lift and store the Dahlias; though planted in a raised bed, this part of the garden can suffer severe flooding during the winter months so the risk in leaving them in the ground is not worth taking as they will likely rot.

Dahlias cut back and ready to be lifted

Use a fork to gently loosen the soil around the tuber and lift the clump, tapping off the soil.  Place the tubers upside down in a crate to allow the water to drain fully from the hollow stems, and leave in this position for about week.  Ensure that they are not left somewhere where rodents can get to them and that they are not left anywhere frosty.

Can you tell what it is? Tubers galore!

After a week place them a box or crate and cover in old compost, coir or vermiculite, keeping the crowns uncovered.  They must be dry but not left to dry out completely, so check the once every few weeks and give them a light watering if ncecessary.  Store them in the dark, again in a frost and rodent free place.

Having dried them, and before packing them away for the wtiner, you can divide the tubers or they can be left in a clumo to divide in the spring.

When done properly, digging and dividing will keep your dahlias returning year after year.  Dahlias left in the ground will create a massive tuber clump underground that will send up many weak, unproductive stalks that have small blooms. Eventually these won’t come back at all.

Dividing Dahlias
Tap and brush all the soil off the dahlia clump. When dividing dahlias, the first thing to do is to remove all broken tubers, remove the original ‘mother’ tuber and remove any tubers that are rotten. You can divide now or keep the cleaned-up clump in tact and divide in the spring. In the spring, the eyes are easier to see. It’s very important to get a piece of the swollen part that is attached to last years’ stem and from which the eyes will emerge.  If your tuber does not have an eye, it will not sprout. Choose only strong, firm tubers. Weak tubers that show signs of rot, shriveling or decay should be tossed and not used in the garden.

Cut surfaces should be allowed to dry thoroughly before they are planted in the garden or stored for the winter. Lay out to dry for 3-5 days in a place that will not freeze, then store for the winter.

In the Spring

Another advantage of lifting Dahlias is that they can be potted up in early spring and with a little heat and protection forced into producing new shoots that can be taken for cuttings.  These should root very quickly if cut off from the junction of the tuber when they are about 7cm (3in) long; do this every year and you’ll have a vast store of Dahlias to brighten your garden late into the year.

If using this approach, the cuttings should be ready to plant out in about July, whilst the parent plant should can go outside in mid-May, or once the risk of frost has passed.  If you choose not to take cuttings in this way then the overwintered tuber can be planted out in early April in good rich soil and at a depth of about 15cm (6in).

The result will hopefully be this:

Dahlia 'Rip City'

Start Sowing now for 2012

I can’t believe it is already that time of year but, yes, I have started to sow biennials for 2012. After making the mistake of leaving it too late last year and ending up with very poor shows of Wallflowers (Erysimum), this year I am on the ball; I did an early sowing of Erysimum cheiri ‘Fire King’ which I have now pricked out and planted on and they’re looking good little plants:

Erysimum cheiri 'Fire King' seedlings

My wife and I have also been busy sowing other seed, some for the garden, some for the cutting garden, and some to sell as plants. So far we have sown: Erysimum cheiri ‘Blood Red,’ ‘Vulcan,’ ‘Ivory Giant,’ and ‘Aurora,’ Dianthus barbatus nigrescens ‘Sooty’ (Sweet William), Dianthus Auricula Eyed Mix and Anchusa azurea ‘Dropmore.’ These are all biennials which will hopefully make it through the winter and be good plants come next spring; they’ll be planted out in late summer once they have reached a decent size and parts of the veg garden become clear.

We’re also growing a number of different Dahlia varieties, mainly in the cutting garden, and for which I have begun to construct a support frame:

Support frame for the Dahlias

The frame will be built up another couple of levels to ensure maxium support for the stems as the grow and for the flowers.  Whilst planting out the Dahlias a few cuttings were taken and they are so far holding up well.  Nothing fancy was done with them, they were cut, trimmed, popped into regular compost and finished off with potting grit in order to keep down weeds and retain mositure:

Dahlia cuttings

I will end this post with a picture of the stunning cerise flowers of Lychnis coronaria. This particular plant grew unexpectedly in the garden and I’m glad it did as the colour is magnificent!

Lychnis coronaria

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