When it comes to gardening, there always seems to be something new to learn. Even experienced gardeners may not know what to do with dahlia bulbs after they have flowered. If you’re wondering the same thing, don’t worry – you’re not alone!
Although dahlias are not particularly high maintenance, learning what to do with dahlia bulbs after flowering will ensure that they return to brighten up your garden year after year.
What are Dahlia Bulbs?
Structurally, dahlia bulbs are short stems with fleshy leaf bases known as scales. These scales do not generally support leaf growth, but they function as a storage organ for food.
This storage organ is what provides energy through dormancy in the winter months and enables the dahlia to grow and flower in the springtime.
The centre of the bulb is an unexpanded flowering shoot from which new stems and leaves emerge and the basal plate is formed by a reduced stem from where the roots will grow.
What to do with Dahlia Bulbs after Flowering?
As we mentioned previously, dahlias are low maintenance and with the right care, they will continue to come back year after year.
Leaving dahlia bulbs in the ground is likely to be the easiest option and you do not require any kind of technical skill to be able to do this although there are a couple of minor things that you will need to think about.
Step 1 – Remove Stem and Dead Head
As soon as the flower has faded and died, you will want to remove the stem and the faded bloom. This is to conserve the plant’s energy stores as the next stage in the plants’ life cycle would be trying to create seeds.
Step 2 – Leave the Foliage in Place
When removing the stem, be careful to leave the foliage in place until it dies back on its own.
The leaves will continue to absorb energy from the sun and through photosynthesis, the sun’s energy is converted into vital sugars that are stored in the bulb for the following season.
Step 3 – Leave Alone
Once all the foliage has died back and the bulb has once again become dormant, there is nothing left for you to do.
There is no need to water the area or tend to it at all until you fertilise in the early spring.
I did tell you that dahlias were low maintenance!
How to Lift and Divide Dahlia Bulbs?
Every 3 to 4 years, dahlia bulbs will self-propagate into clusters that can be separated to form new bulbs.
Steps 1 & 2
Steps 1 & 2 are the same as above. You will want to ensure that you remove the stem and deadhead the flower but continue letting the foliage continue to grow and absorb sunlight, therefore, refuelling the bulb’s energy stores.
Step 3 – Lift Your Bulbs
Once the foliage has all but died back, you can lift your bulbs. Dig an area around the bulbs being careful not to scratch or scar them as this open wound can leave your bulb susceptible to disease and rot.
Step 3 – Clean Your Bulbs
Once your bulbs have been lifted, they will require a clean. It is best to do this with a soft brush. Gently shake off any excess soil and then using a soft brush, give the bulb a gentle clean.
Step 4 – Divide Your Bulbs
Once you have lifted your bulbs and brushed them off, you will see where the new bulbs have formed, and you will be able to just gently break these apart with your fingers.
Important: It is best to replant all of your bulbs old and new immediately in the places you wish them to grow next year.
How to Store Dahlia Bulbs?
If you need to store your dahlia bulbs for any reason, your bulbs will usually keep for a while with no problems. We recommend using a cardboard box for storage as this will let the bulbs breathe as using plastics can cause the bulbs to sweat and rot.
First, put a layer of newspaper in the bottom of the cardboard box and then add your first layer of bulbs being careful to ensure they are not touching one another. Cover with some newspaper and repeat.
You will want to keep your box of bulbs in a cool, dark place such as the garage or basement or somewhere that is not too damp.
Dahlia bulbs are extremely low maintenance and do not really take much in the way of looking after them. As long as you let the leaves continue to grow after the flower has gone, they will still be able to store enough energy to flower the next spring.
Many people will just mow over the leaves once the flower has gone but this is not a good idea as you will end up with stunted dahlias the next spring and that is if they even grow at all.
If you need to lift and store your dahlia bulbs, it is not too difficult either providing you follow the steps that we have laid out for you, you will have beautiful dahlias year after year.
Garden Doctor Tips
“Replant stored bulbs in early spring once the ground has thawed!”
“Do not forget to leave the foliage in the ground until it dies back on its own. The bulb needs the foliage for photosynthesis!”
“Over time, dahlia clusters will expand. Lift and separate bulbs every 3 years and plant a few elsewhere to establish new clusters!”
“If storing bulbs for winter, check on them every 4 weeks to ensure that none of them have rot and gone mushy, if any have, throw them away immediately!”
Frequently Asked Questions
How many years do dahlia bulbs last?
Dahlia bulbs do not really like to be out of the ground but those that are in storage and cared for properly will last around 12 months before they require planting.
Do you have to dig up dahlia bulbs every year?
No, dahlias do not need to be lifted every year. Dahlias will do fine being in the ground through the winter although it is a good idea to lift bulbs every 3 or 4 years to separate the bulb clusters.
Can dahlia bulbs be left in pots?
Yes, dahlia bulbs can be left in pots as long as they are planted deep enough and are protected from heavy frost.
Hi, I’m Trev and I’ve been growing things since I can remember. When I was younger, I grew up on a farm, so I have always been around plants and animals. After studying horticulture at university, I decided to start my own nursery which I have run now for 25 years. In my spare time, I run this website – which is a resource for people who want to learn more about their gardens.