How to grow
Dahlias are native to the sub-tropical highlands of Central America. As warm season plants, they can grow almost anywhere in Australia, but in the tropics they are better suited to highland areas than the coast.
They need sun, but how much depends on where you live. Where summers are warm but not relentlessly hot, they will take full sun. In hotter areas, morning sun with afternoon shade will make them last longer and look better.
Dahlias can only grow fast and produce many flowers in good soil. Enrich your soil with cow manure, compost or both, and fork a generous layer through the soil. After a few months the soil will be breaming with fertility and earthworms.
After planting tubers, keep soil barely moist until growth appears, then increase watering as plants grow, always ensuring soil is lightly and evenly moist. Check for moisture at depth by poking a finger knuckle-depth into the soil – if it feels moist, there’s no need to water just yet. Flower dahlias in pots will need more frequent watering during the summer – at least 3 times a week.
Decorating your home with dahlias is simple, but extremely beautiful as single stems in dainty decorative jars. Don’t worry about any uneven jar height because the stems cut to equal length will make up for that. Dahlia stems are sturdy and strong, and they last about 4-6 days.