How to Plant & Grow


Asters are a whimsical cottage garden and woodland favourite. These pretty daisy-shaped blooms provide a quintessentially British garden vibe that simply cannot be beaten, especially when grown in flower beds or through grass.

Need to know how to plant asters? Let’s dive in! 

What We've Included

When to Plant  |  How to Plant  |  Where to Plant  |  Do you need to Stake Asters  |  After Care  |  Common Issues & How to Solve Them  |  When will they flower?  

When to Plant Asters

Asters are best planted in spring and autumn. Specifically, you should aim to have asters in the ground from March to June for summer varieties, or from September for autumn varieties. This will give them time to establish. 

How to Plant

Planting Loose Roots 
Loose roots to beginners might sound intimidating but are fairly straight forward. Loose roots are dormant plants that have been grown, left to die back, then dug up to be sold without soil around the roots. Here’s how to do plant them from mid-spring.  
- Soak roots in a bucket of water for 1-2 hours before planting.  
- Dig a hole in the border that’s big enough to house the root system. If planting in pots, fill a large pot halfway with potting soil and then pop the roots in with the crown pointing upwards and the root system pointing to the floor.  
-  Plant in groups for a fuller display, usually in groups of 3, somewhere that gets plenty of sunlight.  
- Ensure the crown is just below the soil unless the plant has some leaves, in which case leave them exposed with the rest of the root system under the soil.  
- Water well once planted.  
Planting Modules 
Our modules are incredibly easy to grow and maintain. Whether you’re planting them directly in mid-spring or growing them inside until the threat of frost has passed, modules are a breeze from the moment they arrive. Here’s how to plant them.   
- Dig a hole in the border that’s big enough to house the entire module. If planting in pots, fill a large pot halfway with potting soil and then make several holes that can hold the modules. Do this until the top of the soil from the module is just below the top of the pot.  
- Fill around the modules with soil and firm down gently.  
- Water well and you’re done!  
How to Sow Aster Seeds 
Aster seeds are a more affordable way of growing your favourite varieties. Sow seeds into trays and keep under cover about 3-4 weeks before the final frost. Ensure they’re kept somewhere warm to encourage germination. They can also be sown directly outdoors from mid-spring, once the threat of frost has passed. Prepare a flower bed and sow roughly 1cm deep somewhere sunny. Thin seedlings apart by 45cm when they’re large enough to handle. Once the threat of frost has passed, you can then move indoor-grown seedlings outside. 

Where to Plant

Asters love dappled shade and moist soil. Slightly moist soil that doesn’t dry up will help keep powdery mildew at bay. Perfect for under trees or bushes. They can also be grown in containers if the soil is kept moist. (But not waterlogged). 

Do You Need to Stake Asters?

Some asters can grow quite tall and may need staking to avoid them breaking. You can use a bamboo cane or stake, tying the stem to them to avoid unnecessary damage.

After Care

When to water 
Water well after planting and ensure their soil stays moist, but not soggy. Especially in dry spells, like in summer. Water deeply when you do, rather than a little shower regularly.  
Do You Need to Deadhead Asters? 
 Once asters have finished flowering, many will self-seed. This means that they will drop their seeds, allowing them to germinate and grow again the following year. If you don’t want them to do this, then cut the stems down to the base, just above the soil’s surface.  
However, deadheading asters isn’t necessary to keep a tidy display. Plus, their seed heads provide food for birds and other insects. 

Common Issues & How to Solve Them

Although asters can hold their own, they can sometimes produce powdery mildew. This happens often when they’re kept in dry soil that isn’t often watered. Simply keep their soil moist to mitigate the risk of developing powdery mildew. 

When will Asters Flower?

This will depend on the variety you’ve bought. Some asters flower in summer, whereas others will flower in autumn. Double check the product description when buying to know when they’ll flower.