How to plant dahlias

How to plant dahlia tubers

• Dahlias will grow in most soil types but are best planted in fertile, well-drained soil.
•  Plant them outside from the end of April after the chance of frost has gone. 
• Ensure they are in a spot that receives full sun and plant around 15cm deep adding well-rotted organic matter.
• Keep your dahlias well watered during the summer months and feed every couple of weeks with high potash feed as the flowers appear.

What Month to plant dahlia tubers?

You can plant them straight in the ground in April. Many people grow them from March in greenhouses. This allows the tubers to start early and flower sooner in summer. 

• Put them in a pot just big enough for the tuber
• Use good compost that drains well
• Place in plenty of light but protected from frost.
• Remove from the pot and plant straight into the ground once the threat of frosts has passed. 

Give your dahlias a good start

Provide protection from slugs for your young plants to stop them feasting on the tender, fresh shoots.  

It is also a good idea to ward off earwigs which are fond of young plants. Simply fill small pots with straw and put on them on top of canes near your dahlias. The earwigs will shelter in the pots during the day and you can clear these little fellows out in the late afternoon.

Pinching new growth from dahlias

When the dahlias are around 30 cm high, pinch out the growing tips to encourage the plants to branch out and produce more flowers. Also remove any stems that look weak.  For stronger stems and longer flowering, pinch out the buds that develop in the base (axel) of the stem.  Larger dahlias will need staking. 

Always remove the flowers as soon as they show signs of fading in order to promote more flower production.

Explore different types of dahlias

There are so many shapes and colours to explore, there's something to suit every garden. It doesn't matter what type of dahlia you are planting, the tubers require the same treatment. 

• Anemone Dahlias
• Bishop Dahlias
• Cactus Dahlias
• Collarette Dahlias
• Decorative Dahlias
• Single dahlias
• Gallery Dahlias
• Happy Single Dahlias
• Karma Dahlias
• Pompon and Ball Dahlias
• Star Dahlias

Flowering until the first frosts

Overwinter dahlias

• In winter allow the first hard frost to turn the dahlias black. 
• Cut them down to around 15cm then carefully lift them from the ground. 
• Gently shake off any excess soil and turn upside down on paper to allow the water to seep from the tubers. After a few weeks they will be completely dry. 
• At this point, shake loose any remaining  soil and dust with yellow sulphur to protect them from mould and mildew. 
• Store in a frost free place in a container filled with dry to moist peat or sand for winter.