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Home » Growing Guide » Dahlias Growing & Planting Guide

Dahlias Growing & Planting Guide

Dahlia Orange - Garden Express Australia

No summer floral display is complete without striking, sculptural dahlias. With a dazzling range of forms, colours and sizes to choose from, there’s something for every garden. Borders (both tall and low), mixed beds and pots can all be coloured in with these vibrant beauties, which also make wonderful cut flowers.

The good news for fans of these impressive flowers is that they’re not too difficult to grow. Now is the time to get started, with spring to early summer being ideal for getting dahlia tubers in the ground. Depending on what variety you choose, you’ll see flowering from summer through autumn, and in some cases (such as with tree dahlias) even into early winter.

The Season Ahead

So, what do you need to know to make the most of the upcoming dahlia season? Half the battle is choosing what type of dahlias to plant. Along with bloom type, be sure to pay attention to the weather resistance and eventual growth size of the different varieties with respect to your available space.

For example, cactus dahlias are less likely to be weighed down by rain (so they don’t need as much staking as other types), while Delbard varieties are hardy and drought tolerant.

Once you’ve got your tubers, get ready to enjoy them for years to come. Here’s what you need to know about their life cycle.

Ball Dahlia - Garden Express Australia

Ball Dahlia


In Australia, October to November is a good timeframe to plant, especially if you want to see blooms around Christmas and new year.

Choose a position with full sun to light shade, protected from strong winds as much as possible. Use a well-drained soil enriched with plenty of well-rotted organic matter.

Plant tubers 10cm deep, with the growing tip facing up, and water in well. Mass plantings look great – plant at a density of around 60cm apart.

Tall varieties will need staking, and you can do this at planting time to minimise damage to the tubers.


Except in very dry conditions, water only lightly until the plants have grown to around 15cm high. An excess of water can cause the tubers to rot before they’ve had an opportunity to grow.

As the plants grow, they may need staking to stop them from toppling over, especially in wind or after rain (many of the flowerheads trap water, which weighs them down).

Cut flowers last up to a week in a vase, making dahlias a popular addition to arrangements. Cutting/picking flowers for this purpose, or deadheading if you prefer to leave them on the plant, will encourage further flowering.

Flowering usually winds up towards the end of April or in early May. Once this has happened, you can tidy them up by trimming to about half their height. When the leaves change colour, cut them off at ground level for their dormant phase.

Dahlia Lemon Snow Pkdahlsn - Garden Express Australia

Dahlia Lemon Snow


While dahlias are often happy to be left undisturbed for years, we recommend lifting and separating every second winter. This is especially necessary if your soil gets wet over winter, as this can cause the tubers to rot – for this reason, it’s best to start with well-drained soil.

When lifting, you’ll need to make sure they don’t dry out entirely. Covering them with dirt or sawdust will storing will help avoid this.

When dividing tubers, make sure each division has some of the old stem attached, as this is where the new growth will emerge from.

When spring rolls around again, the tubers are ready to be replanted, and the cycle begins again.

Dahlia Varieties

Garden Express has a huge selection of dahlia varieties in stock. See our range here, and get ready for dahlia heaven!


Top Picks For 2019

Dahlia Kenora Wildfire 14 - Garden Express Australia

Dahlia Kenora Wildfire

Dahlia Little Angel Pkdahlan 1 - Garden Express Australia

Dahlia Little Angel

Dahlia Edinburgh 14 - Garden Express Australia

Dahlia Edinburgh








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