The familiar, daisy-like appearance of Asters makes them a popular choice for UK gardens. Find out more about these lovely plants and find some suggestions for varieties you can grow at home.

What is the scientific/botanical name for Asters?

The scientific and botanical names for this lovely flower include Aster, Callistephus, Eurybia, Kalimeris, Symphyotrichum.

However, you may find the following names more recognisable: Michaelmas daisy, aster, China aster, and New England aster.

They get the name ‘Michaelmas daisy’ because they are often seen blooming around the time of the feast of the archangel Michael, at the end of September. There is even an old rhyme which features this explanation.

It goes: ‘The Michaelmas daisy, among dead weeds, Blooms for St Michael’s valorous deeds. And seems the last of flowers that stood, Till the feast of St Simon and St Jude.’

Where are asters native to?

Plants of the Aster genus are most commonly native to Europe and Asia, however, there are a couple of varieties native to North America.

The name ‘Aster’ has origins in ancient Greek! ‘Asteri’ translates roughly to ‘star’, and so the flower got its name thanks to its starlike appearance.

There is even a Greek myth surrounding the origin of Asters, the flower being the product of the goddess Asterea’s tears.

Wild asters growing on a coastal rock

What do asters look like?

Asters share a striking resemblance to daisies but in a fantastic variety of colours. The flowers emerge from a clump of sea-green leaves on dainty stems.

What colours do asters come in?

The blooms can come in pink, lilac, purple, red, blue, or classic white.

Asters growing in a variety of colours

Where do asters like to grow?

Asters prefer slightly moist soil, so anything that can retain moisture well. They enjoy full sun but can grow well in dappled or partial shade too.

Where do asters dislike to grow?

Well-drained soil is best avoided, as if the soil dries too much the Aster will struggle. There is also a chance waterlogged soil could be problematic. Also, Asters prefer not to be in too much deep shade.

How do you grow asters successfully?

Know which Aster you are growing. Recently, many varieties have been reclassified under a different genus name, and these have different growing requirements. For example, Tripolium varieties have more succulent leaves, so require less frequent watering.

Most aster varieties flower from mid-summer to mid-autumn, with many varieties first flowering in late September. They will continually bloom until mid-autumn, which can be promoted by deadheading faded flowers.

Asters growing in the sun

Generally, Asters are easy to grow and low maintenance. They are hardy and don’t require too much watering (unless in containers).

The only common problem you will find is powdery mildew.

Asters can live for many years, provided you lift and divide them in three to five-year intervals.

You will know it’s time when the centre of your flowers are dying and the stems won’t support the flowerheads well by flopping.

Are asters good for pollinators?

Yes, Asters are great for pollinators. They provide a late-year supply of pollen, as they flower in late September.

How to choose the right asters for your garden?

There is a variety of Aster for many different purposes and locations in the garden. There are some taller varieties which are perfect for some colour at the back of your borders.

Shorter varieties are ideal for growing in containers, and those that are hardier for changing weather conditions. Clump forming is also great, as they will fill your container with a lovely colour.

There are even varieties of Aster that will perform wonderfully in a rock garden. Thanks to their origin in mountainous areas of Europe and Asia, they grow well in these conditions.

Even if you want to grow Asters to use as cut flowers, either for your own displays or as gifts, there are plenty of ideal varieties. Aim to grow Asters with long, upright stems, which will grow well for cut flowers.

Asters growing in a container
Asters growing in a rock garden

How big will my asters get?

This completely depends on the variety that you choose. The average variation in height is anything from 40cm (16 inches) to 1.2 metres (4 feet) in height. Spread is a little more consistent, sitting at roughly 45cm (1.5 feet).

How to plant asters?

First, you want to plant your Asters in early spring, between March and early May, depending on the hardiness. Try to make sure any risk of frost has passed. This will give them plenty of time during the growing season to establish before flowering in autumn.

You can also grow Asters from bare-root, which you will want to plant as soon as possible after they are delivered.

To plant your Asters in the garden, start by digging in some peat-free garden compost or well-rotted organic matter into your soil. This will improve your soil structure and fertility.

If you’re growing in containers, first choose a container at least 20-23cm (8-9 inches) in diameter, to give your Aster plenty of room. Use peat-free, multipurpose compost, and then position your container somewhere warm and sunny.

How to care for asters?

In the ground, water your Asters well after planting. Make sure the soil around the roots is constantly slightly moist, but not waterlogged. The amount of water your Aster gets can impact how tall it grows. If growing in containers, water more regularly. If the weather is particularly hot, it is likely that you will need to water them daily.

Overall, Asters don’t require feeding too regularly. However, mulching any garden borders every spring should be more than enough to keep them fertile. Use well-rotted organic matter, or peat-free garden compost to mulch.

Many varieties are very hardy in the UK, so don’t require too much attention to overwinter. However, your Asters getting too wet in the winter is more likely to cause problems. Lifting and dividing your Asters every three to five years is advantageous and is best done in early spring.

How do I keep my asters looking good?

Asters are prolific flowerers, but if you want to encourage more flowering, deadhead any faded flowerheads. This is particularly helpful if you are growing China asters (Callistephus chinensis).

There are some varieties of Asters which benefit from cutting back in late May or early June. The technique for this is called the ‘Chelsea chop’, so called because the date corresponds with the famed flower show.

If you are growing any particularly tall Aster varieties, it may become necessary to stake them. Try to find out if the variety you are growing is projected to grow to over 1 metre (3.3 feet). If it is, consider putting some support in before the middle of summer. Symphotrichum novi-belgii is a great subject for this and performs well as a result. To do this, cut back the clumps to between one-third and a half of its previous size. This means the plant is less leggy, is less likely to require staking and produces a higher volume of blooms.

Healthy looking asters

How do I propagate asters?

There are a couple of different methods for propagating Asters. Every three to five years when you divide them, you can propagate the clumps separately, producing more individual plants.

Otherwise, you can propagate via softwood cuttings between April and August. This process can over 2 years to produce flowering plants.

To propagate by cuttings, remove any non-flowering shoots, and the lower leaves of your cutting. Push into moist but gritty compost, and cover with a clear plastic bag. Make sure the compost is moist regularly.

Within six to eight weeks, you should see signs of growth from your cuttings. At this point, you can pot your cuttings into their own individual containers. Then, plant them out in spring. You should see flowers from them the following year.

What problems can Asters have?

The most found problem in Asters is powdery mildew. You can purchase mildew-resistant varieties, and you may find Symphotrichum novi-belgii Asters to be the most vulnerable. When watering, avoid spraying the leaves. Try to grow your Asters in moisture-retentive soil if you can and ensure the soil doesn’t dry out.

Within six to eight weeks, you should see signs of growth from your cuttings. At this point, you can pot your cuttings into their own individual containers. Then, plant them out in spring. You should see flowers from them the following year.

What varieties of asters should you look out for?

Here are some great Asters to grow at home for different parts of the garden:

Symphyotrichum-novae-angliae-James-Ritchie back of the border
Symphyotrichum novae-angliae 'James Ritchie'

Back of the border

A perfect Aster for the back of your garden borders is Symphyotrichum laeve ‘Calliope’. It reaches up to 1.5 metres (3.3 feet). This will make for a delicate and colourful feature to support your garden border in a lovely lilac shade.

For an even brighter Aster at the back of your border, Symphyotrichum novae-angliae ‘James Ritchie’ is a striking shade of hot pink with bright golden centres. This is sure to draw the viewer’s eye upward.

Callistephus chinensis Milady series front of the border
Callistephus chinensis Milady series

Front of the border

With their double flowerheads and shorter height, the Callistephus chinensis Milady Series are perfect Asters for the front of the border. Their bold colours guarantee they will stand out.

Symphyotrichum ericoides var. prostratum ‘Snow Flurry’ will provide a blanket of white blooms at the front of your borders. Their dark green foliage contrasted with bright white petals will stand out well against the rest of your border’s display.

Symphyotrichum ericoides golden spray
Symphyotrichum ericoides 'Golden Spray'

Containers

For a wonderful sprinkling of flowers in your containers, Symphyotrichum ericoides ‘Golden Spray’. These beautiful sunrays of blooms will brighten up your containers, and are fully hardy in the UK.

For a more colourful container option, Symphotrichum ‘Coombe Fishacre’ is another wonderful choice. It has lovely flushed-pink petals which converge on yellow or dark pink centres. Sure to attract attention to your pots and containers!

Aster amellus Veilchenkonigin
Aster amellus ‘Veilchenkönigin’

Cut flowers

A great compact Aster for cut flowers is Aster amellus ‘Veilchenkönigin’. With upright stems to 40cm, and deep-violet blooms to 5cm across, they will make for a wonderful cut flower display.

For a soft pink cut flower option, Symphyotrichum nov-belgii ‘Fellowship’ is a great choice. With blooms up to 6cm across, add these to your Autumn cut flower displays.

Kalimeris incisa 'blue star'
Kalimeris incisa 'Blue Star'

Rock gardens

To add some soft colour to your rock gardens, consider Aster tongolensis. With their lavender-blue flowers, they will stand out against the stone, and grow well in well-draining conditions like rock gardens.

For a hint of subtle blue colour, the Kalimeris incisa ‘Blue Star’ will deliver. Standing out against their dark green foliage, they will make quite the striking addition to your rockeries.

When should I buy asters?

You can buy asters in garden centres from mid-to-late spring, which you can plant out straight away once any risk of frost has passed. Otherwise, you can purchase them already flowering in late summer to early autumn. You will need to water them regularly to help them establish.

Which garden design styles do asters work best in?

Asters grow well in cottage, prairie, and mixed garden designs. Some varieties also grow well in rock gardens.

This September, grow some asters for some lovely autumn colour and interest in your garden borders and containers.

For some wonderful and colourful options to grow in September:

September top 10 feature image 2023

Or check out my Pinterest board for more ideas: