Dahlia planting guide

Dahlias are gorgeous plants, available in a range of stunning colours and styles. Whether planted directly into a garden bed or placed in pots, these wonderfully eclectic flowers are a welcome addition to spaces large and small.

The great news is that dahlias don’t require a lot of care. They’re easy to grow, so even those that are new to gardening should be able to get them to thrive.

If you love the look of these flowers, you may be interested in learning how to grow dahlias in your garden. Read on for tips and tricks on growing dahlias in this dahlia planting guide.

Types of dahlias

Dahlias come in many different varieties, with fun and unique features that set them apart. 42 species of dahlia exist, with each one boasting a distinct look. These flowers also come in a wide range of sizes, some are as small as 5cm in diameter, while others can be up to 30cm in size.

With choices of small, spherical flowers, pointed petals, or open blooms that reach up to the sunlight, there are many options to decide between when planting dahlias in your garden. Dahlias are closely related to chrysanthemums, sunflowers, and daisies, so you may see elements of these flowers coming through in the plants.

Some common types of dahlias include:

Cactus dahlias

The narrow petals of these flowers give them an almost spiked look. Within this variety, there are many subtypes and colours to choose between, including multi-toned options, as well as miniature and giant options.

Waterlily dahlias

Named as they look remarkably like the waterlilies you may see floating in ponds, waterlily dahlias have many shallow petals that sit around the inner section of the flower. They come in lots of different colours from bright reds to pastel pinks and yellows.

Single dahlias

With a bit more of a “typical” flower look to them, single dahlias have petals arranged around the centre of the flower. Many subtypes exist within this variant, with some flowers having pointed petals while others have rounded ones.

Ball dahlias

Unique and eye-catching, ball dahlias have petals arranged in a spherical shape that often includes a spiral pattern. These flowers poke out on stems and come in many colours to brighten a garden area.

Pompom dahlias

This type of dahlia has a similar look to ball dahlias but is a little smaller. The spheres contain petals that have an inward curve, with lots of different colour options to choose from.

Where is the best place to plant a dahlia?

Dahlias love the sunshine, which makes them well-suited to the bright Aussie climate. When choosing a spot for planting your dahlias, try to pick somewhere that receives plenty of sunlight. Between 6-7 hours of sun a day is ideal. Also, make sure to plant them somewhere away from gusty winds that might blow the shrubs about as they dislike too much movement.

These plants also aren’t very fond of the cold. If you live in a spot that experiences frosts and cold weather, you’ll want to remove the tubers from the ground before the winter comes or Don’t worry, you can simply plant them back when it begins to warm up again in the spring. If the area you live in isn’t too chilly, you may instead like to cover the soil with mulch to protect them.

Plant your dahlias directly in the soil (if it’s well-draining) or in pots for moveable blooms that you can place around your garden or balcony.

How to grow dahlias

Growing dahlias is a relatively simple task, even for novice gardeners. They’re easy enough to care for and won’t require a lot of your time or energy to be happy and healthy.

Here are a few steps you can follow to begin your dahlia-growing journey.

Step 1: Choose the right time

When planting your dahlias, it’s important to choose the right time of year to get the best results. Try to plant these flowers in the springtime. September to November is the peak planting time for these plants. The tubers generally take around two months to flower after being planted, so take this into account and plan accordingly if you have an event you’d like them blooming for.

Step 2: Select the variety

With so wide varieties to choose between, it can be a little overwhelming trying to choose which ones to plant! If you simply can’t decide, pick a couple of different types to have a go at growing in your garden. Different types of dahlias can be placed together in large pots or in the ground for a fun and varied look.

Step 3: Acquire your tubers

While you can grow dahlias from seeds, it’s easier to grow them from tubers. Planting dahlia tubers allows you to know exactly what you’ll get from the plant, whereas planting these flowers from seed may lead to mixed results. You should be able to find the tubers for the types of dahlias you wish to plant in specialty stores online. Your local nursery may also stock a variety of dahlia tubers to choose from.

Step 4: Prepare the soil

Dahlias grow best in soil that’s well-drained and rich in nutrients. They like to be kept a little moist, without becoming waterlogged. When preparing the soil for planting dahlias, mix in plenty of organic matter to boost the nutrients for the plants – this could include manure, compost, or leaf matter.

Step 5: Plant your tubers

Once the soil is adequately prepared, it’s time to plant your dahlia tubers. To do this, dig a hole about 15cm deep and carefully place the tubers inside before covering them with soil. Make sure you leave plenty of space between tubers to allow them to spread out as they grow. About 30cm of spacing should be enough.

Step 6: Don’t be too quick to water!

While it may be a bit of a habit to water new plants as soon as you’ve covered them with soil, it’s generally best to hold out on doing this with dahlias if the soil you’ve planted them in is already a little moist. Adding too much water to the tubers can cause them to rot rather than grow. If the soil you’ve planted the dahlia tubers in is wet, plant them, then leave them alone until they reach around 10-15 cm tall. If it’s dry, give them a thorough watering straight after planting and then leave them until they reach this height. In both scenarios, you may like to give these plants very occasional water if you feel they need it, but be careful not to drench them.

Caring tips for dahlias

As mentioned above, caring for dahlias is a relatively simple task. These plants are quite resilient and don’t require a lot of fussing to stay healthy and bloom. However, you can do a few things to ensure your plants are getting everything they need.


Be careful not to overwater your dahlias, particularly when they’re first planted and the tubers are beginning to sprout. Once the plants have taken hold, you can begin to water them more regularly. Try to keep water off the leaves, where possible, instead choosing to water at the base of the plants. Watering these shrubs deeply one or two times a week should be sufficient to keep your dahlias happy. Alternatively, you might like to install irrigation to provide a consistent, deep watering system for these plants.


Add organic mulch to the base of the plant during warm summers to help protect the shrub from hot days. This could be straw, pine chips, or other suitable organic material. If you live in an area that experiences milder winters, you may also be able to get away with mulching the soil during the winter to keep the tubers protected from the cold, rather than digging them out to keep them safe.

Pruning and deadheading

Pruning your dahlias will encourage thicker growth and cause your plants to spread out and fill the space more. To do this, pinch off new tips as they begin to grow. Once flowers are blooming, cut them from the plant and more flowers should take their place. Remove dying flowers and regularly deadhead the bush by cutting the flower where it intersects with the nearest leaf. After a few months, you’ll likely notice the rate of flowering beginning to fade. When this happens, simply cut the shrub back to half its size and wait for the leaves to begin dropping or withering. At this point, cut the plants right back and either mulch the ground to protect the tubers below from the winter cold or remove them from the soil altogether.


Fertilising your dahlia plants will give them additional nutrients, helping them to grow well and produce lots of beautiful blooms. A general-purpose fertiliser should be applied around the plant and watered into the soil once they reach around 25-30cm tall. Fertiliser can also be applied regularly once flowers begin to bloom to extend their life.

We hope you’ve enjoyed reading through our dahlia planting guide and learning more about these wonderful flowers. Dahlias are relatively easy flowers to care for, and produce some amazing blooms to brighten up your garden during the late spring and summer months. With so many beautiful varieties to choose from, you’re sure to find one (or a few) perfect for your space!

For a more professional looking garden, don’t hesitate to call the experts at Jim’s mowing. Learn more about our comprehensive range of professional gardening services.

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