In my last garden, I planted some Dianthus around the border of a large garden bed and they never failed to impress me with their colourful blooms throughout spring and summer.
While the varieties I grew were perennials and would continue to bloom year after year, there are also annual species that are ideal for hanging planters and pots. In fact, there are around 300 species of Dianthus and many more cultivars and hybrids.
For those who don’t know, Dianthus are closely related to carnations and their common name is ‘pinks’ because their frilly leaves look like they’ve been cut with pinking shears.
When to plant dianthus in Australia
You can grow Dianthus from purchased seedlings which are readily available in spring and beyond.
These can be planted in the garden from spring to autumn if you live in a temperate climate. However, in cooler areas, limit the planting time from spring to summer so that plants have plenty of time to get established.
It’s also easy to grow Dianthus from seed. You can start these in punnets or sow them straight into the garden. Wait until the soil has warmed up in spring.
Climate requirements for dianthus
Dianthus can successfully be grown in most climates around Australia including sub-tropical to cold.
They tolerate the cold well but are susceptible to fungal problems in areas with high humidity.
How to plant dianthus
Choose a sunny spot in the garden. Dianthus will tolerate part shade but will bloom better when grown in full sun. The soil should be free-draining with some organic matter added before planting.
Dianthus also prefers slightly alkaline soil. So, if your soil is on the acidic side, add a handful of Dolomite lime in order to raise the pH.
Planting dianthus seedlings
You can purchase seedlings in punnets at a garden centre or nursery but they are also often available in small pots. These plants look best when you mass-plant them along a border.
Space your plants around 30 cm apart and water well after planting. Apply some controlled-release fertiliser or use an application of liquid fertiliser mixed with water.
It’s not recommended to add mulch around these plants as this may encourage root rot.
Sowing dianthus seeds
Growing dianthus from seeds is just as easy as planting seedlings and relatively more economical. All you have to do is prepare the soil, add some compost, and a handful of lime if the pH is below 7.0.
Scatter the seed over the soil where you want the plants to grow and just cover lightly with soil. Water well after sowing but make sure that the soil can drain freely. It will usually take around 7 to 14 days for the seeds to germinate.
If you sow the seeds in spring, you won’t get any flowers in the first year. It’s better to sow in late summer so the plants have time to establish and flower the following spring.
You could also start your seeds indoors in late winter around 8 weeks before the last expected frost if you live in a colder climate.
How to care for dianthus
There’s really not much to caring for dianthus once they’ve become established in your garden. Unless you’re experiencing a prolonged dry spell, they should be able to survive just on rainwater.
You also don’t need to worry about applying regular fertiliser, especially if you’ve added this at the time of planting. I never added any additional fertiliser to my plants and they continued to flower year after year.
The only thing I would sometimes do is sprinkle them with some diluted liquid seaweed such as Seasol.
If you want to extend the blooming season for these gorgeous plants, then it’s important to deadhead the spent blooms regularly. This will promote new flowers to grow.
How to grow dianthus in pots
Growing dianthus in pots is just as easy as growing them in the ground. Choose a pot that has good drainage holes and use a premium potting mix.
You just need to ensure that you water the pots when the top few centimetres of soil is dry.
Dianthus problems, pests, and diseases
I never had any pest or disease problems with the Dianthus I grew in my last garden.
However, some gardeners may have a problem with slugs and snails when the plants are young. Scattering a few Multiguard snail and slug pellets around the plants will help.
Popular dianthus varieties in Australia
There are many different varieties of dianthus that can be grown in Australia. Some of the more popular ones include:
Dianthus barbatus (Sweet William)
You’ll love the pink and white clustered flower heads on this variety. It will survive a little better in slightly damp soils but the soil must still be free-draining.
Dianthus carthusianorum (Carthusian pink)
With flowers ranging from white to pink, this bushy variety will spice up your garden. The flowers have a lovely spicy scent that will fill the air on a warm summer’s day. This is one of the taller growing varieties and will reach a height of 60 cm.
Dianthus plumarius (Garden Pink)
The flowers on this variety are just gorgeous as the edges of the petals are heavily fringed. This gives them a delicate appearance. This is quite a compact plant and is ideal for filling a border around a larger garden bed.
FAQ
Is dianthus annual or perennial?
You can get both annual and perennial varieties of Dianthus in Australia.
Do you cut off the dead flowers on the dianthus?
Yes, this is important if you want to prolong the blooming season because it will encourage new flowers to grow.
How do you keep dianthus blooming all year?
Commonly, dianthus will bloom for quite a long time from spring right through autumn if you deadhead the spent blooms regularly and apply some organic liquid fertiliser high in potassium.
