What to Do When Your Dahlia Tubers Arrive
When your dahlia order arrives in spring, you might be surprised at how simple they look. Each one is a single tuber — a small, potato-like root with all the energy it needs to grow into a full-sized plant. Don’t be fooled by their humble appearance: given the right conditions, that little tuber will transform into a summer showstopper covered in blooms.
Check and sort
Open your parcel straight away. Tubers should feel firm and plump, with a visible “eye” or growth point near the crown. Don’t worry if there’s a little dryness — that’s normal. But if you see mould or rot, cut it away with a clean knife and dust the wound with cinnamon or garden sulphur to help it heal.
Store well
If the soil is still cold or frosty outside, don’t rush. Store tubers in a cool, dry spot with good air circulation — a cardboard box with wood shavings, newspaper, or sawdust works well. Avoid plastic bags, which trap moisture.
Start early
For an early jump, you can “wake up” your tuber in a pot indoors. Use a free-draining potting mix and keep it lightly watered in a nice warm spot until shoots appear. Once the weather has settled, transplant it into the garden.
Plant out
In the Yarra Valley, we don’t plant until mid-October, once frosts have passed and the soil has warmed. When you’re ready, dig a hole around 10–15 cm deep. Place the tuber on its side with the eye facing up. Cover lightly with soil, leaving space to backfill as shoots grow. This helps protect the young stems from slugs, snails, and sudden cold snaps.
Dahlias grow tall and heavy with flowers, so they require support as they increase in height. At Shortacre, we add our system when plants are about knee high. We set star pickets at the corners of the beds and stretch thin wire mesh (the insulation style) horizontally across. As the dahlias grow, the mesh holds them upright and prevents the canes from collapsing under the weight of the summer blooms. Whatever system you use, adding support before the plants get too tall makes all the difference.
The reward ahead
There’s something grounding about tucking a dahlia tuber into the earth each spring. By summer, that unassuming root will have transformed into a towering plant heavy with flowers — perfect for picking, arranging, and sharing.
For the longest vase life, pick dahlias when the blooms are three-quarters open — the petals should be fully coloured and starting to unfurl, but the centre not yet blown out. Always cut stems early in the morning or late in the evening, when plants are cool and hydrated.
To keep your patch flowering, it’s just as important to deadhead. Remove spent blooms all the way back to a leaf node or side shoot, rather than just snapping off the flower head. This signals to the plant to send up fresh stems, rewarding you with more flowers right through the season.
Don’t be surprised if the first flowers of the season look a little different to what you expected — they can be smaller, uneven, or not quite true to form as the plant gets going. By mid-season, the blooms will be at their best. Towards the end, the flowers still come thick and fast, but the centres can blow out more quickly in the heat. It’s all part of the natural rhythm of the dahlia season.
