Dahlias are simply stunning flowers, but in order to grow them successfully in the UK, you do need to take special care of them. Most of this work usually comes once they have finished flowering, so let’s have a look at what to do with Dahlias once they have finished flowering.
What To Do With Dahlias After Flowering?
When your dahlia flowers begin to fade the first thing you should do is deadhead the spent blooms, this will encourage the production of more flowers.
When the winter frosts start to arrive and your Dahlias begin to blacken and die back then you need to think about protecting them over winter.
There are different schools of thought when it comes to dahlias and protecting them overwinter. The traditional way to protect Dahlias is to dig them up and store them overwinter.
However not everyone has space for this, or indeed the time, as a result leaving your Dahlias in the ground, with some protection, is a method that is gaining in popularity.
I will talk about both methods here and hopefully, help you find out which is the method most suited to you and your garden.
Deadheading Dahlias
As you should with pretty much all flowers, deadheading Dahlias is essential to getting the most out of these plants.
Deadhead spent blooms by removing the full stem with a pair of sharp secateurs or scissors. It can be tricky to tell the difference between a flower that has finished and a bud that hasn’t opened yet.
Buds that are going to flower tend to be nice and round, leave these well-alone, spent blooms tend to be more shrivelled and have uneven shapes.
Here is a Dahlia bud that has not opened yet, you can see that it is fairly round. I picked one that isn’t perfectly round just to show you how if you are not paying full attention you could easily deadhead buds which were about to open.
Spent blooms will be a lot more uneven than this and usually have bumps and ridges in them.
Lifting and Storing Dahlias
If you are going to dig your Dahlia tubers up and store them over winter then follow my quick guide below to ensure you give them the best chance possible.
To begin with, you will want to cut the foliage back almost to the base of the plant.
Once this is done gently lift them using a garden fork. You want to dig well away from the plant, to begin with, to make sure you don’t accidentally stick your fork through the tuber.
Remove any soil from the tuber by giving it a good shake and also a quick brush with your hands. I then like to leave the tubers in the sun for a few hours to dry out.
If the weather is poor then move them into a greenhouse or put them on a windowsill for a while to dry.
You then want to hang them upside down for a couple of weeks to make sure they are really dried out. Now, this obviously needs to be done in a frost-free place as the tubers are really vulnerable at this point.
If an early frost is forecast then you may want to consider bringing them inside.
After a couple of weeks of hanging, they will be ready for their winter hibernation. Wrap them in one or two sheets of newspaper before storing them over winter. You want a frost-free spot but one that also has decent ventilation.
A garage shed or greenhouse is usually a good idea. (depending on the weather greenhouses can get a little chilly so this really depends on your location and the weather that winter)
Leaving Dahlias In The Ground
If you have a smaller garden and no greenhouse or garage in which to store your Dahlias then it may be better for you to leave them in the ground.
This is also true for gardeners who want to enjoy Dahlias but just don’t have the time to dedicate to digging them all up and planting them all over again next year.
To start with you want to remove all vegetation from the plant right back to the base. Use some good secateurs for this as Dahlias can have tough almost woody stems.
You then want to apply a really thick mulch on top of your Dahlias, this is the secret to protecting them over winter. You want to use a bucket full of mulch for each dahlia and leave it piled up, one bucket high.
You can use compost, leaf mould, bark, anything really as a mulch just make sure it is really thick. This should help prevent the ground underneath from freezing which will, in turn, protect your dahlias.
Conclusion
When your Dahlias have flowered you should first deadhead the old flowers to encourage the production of new flowers.
Once the winter is starting to draw in and your dahlia begins to die off then you need to think about protecting it over winter. You can mulch the tuber heavily and leave it in the ground or lift it and store it overwinter before replanting it next spring.