London (change)

Dahlia and cosmos pot display


Dahlias come in a fascinating variety of shapes and sizes, and the pom-pom types, with their rows of incurved petals, resemble old-fashioned bathing caps. Dahlia 'Franz Kafka' lends itself - ironically, given its name - to a relaxed cottage-garden style, floating like balloons above the feathery foliage of Cosmos 'Sensation' and its delicate, pink petals.

Use a large container for this display, as this combination of plants reaches 1m in height. Prevent the planting scheme from looking too top heavy with a skirt of cerinthe. Its silvery blue leaves lift the dusky pink and purple flowers beautifully.

Plant it: sow in early spring, pot on in April, plant out in June
At its best: summer
Takes just: an hour

How to do it:

Adding cardboard to the container


If you're using a metal container, line the sides with cardboard to prevent it from heating up and drying out the compost.

Adding compost


Half-fill with multi-purpose compost and add gravel for drainage.

Planting up the pot


Plant up the centre of the container with dahlias and cosmos, and the front and sides with cerinthe.

Watering the plants


Backfill with compost, and firm gently to remove air pockets. Water well and place in a sunny location.

Discuss this pot & container

Talkback: Dahlia and cosmos pot display
Your comment will appear after a quick registration step

Guernsey Donkey2 04/03/2016 at 19:37

Do you have holes in this galvanized metal bath - if not how do you prevent it from becoming water logged?

Logan 05/03/2016 at 10:27

Yes you do need holes the plants won't like it unless you're growing bog plants

Verdun 05/03/2016 at 13:02

 Cosmos and dahlias together in a pot?? 

A vigorous dahlia will simply swamp the cosmos.  A dwarf vsriety will be swamped by tall cosmos.  Not a partnership for me