How to prune Aster Novae-Angliae (New England aster)

Why prune Aster Novae-Angliae?

Aster Novae-Angliae (New England aster) is a classic autumn bloomer with full, fragrant flowers in deep purple, pink and white. The plant naturally grows very upright and strong, but quickly becomes too tall (100+ cm) and falls over in rain or wind. Left unpruned, you get a sparse, floppy plant with flowers too high to see.

With targeted pruning in May and June, you build a compact, sturdy plant with full blooms lower in the plant. The plant stays upright and looks really attractive.

Natural growth pattern

Aster Novae-Angliae grows as an unbranched upright stem in spring. From May side shoots appear. Without intervention, the plant grows to 120-150 cm and flowers only at the top. The bottom is bare and uninteresting.

So: pruning is not wrong - it is the only thing that makes this plant look good.

Step 1: First pruning (May)

Early May, when your plant is roughly 20-25 cm tall. This is the time for the first cut.

Cut off the top of the plant, roughly 5-10 cm from the apex. This sounds harsh, but it works: you massively stimulate the plant to branch. Instead of one central stem you get four to six strong side shoots growing from the same height.

Practical tip: May, sharp secateurs, just cut the top off. The plant now looks topped - that is correct. Do not worry - it regrows fast.

Within two weeks you already see small side shoots growing from every bud below your cut. Within a month your plant is much fuller and denser.

Step 2: Second pruning (June)

In June, when the plant has grown another 20-25 cm. This is the time for the second pruning.

Look at your plant. You now probably have four-six strong side shoots. Cut each of these side shoots back again to roughly 5-10 cm from the apex. This is the second "layer" of pruning.

Once again the plant looks diminished, but it is healthy. Each cut shoot will now form two to three new side shoots. Your plant becomes exponentially fuller.

Step 3: Prevent collapse (July-August)

After two pruning sessions, your plant is now compact (40-50 cm) and very full. After July you need not do much more.

Check in August whether the plant still grows upright. If certain stems get heavy or bend outward, thin them lightly. But usually two prunings are enough.

Step 4: Let grow and flower (September-October)

From September onward, your Aster Novae-Angliae blooms abundantly. The plant is now at roughly 60-80 cm height when mature - much shorter than unpruned specimens, but fuller and stronger.

Let the flowers grow now. You need not cut anything more. Enjoy!

Step 5: Autumn care (October-November)

As October wanes and frost arrives, your plant dies back. Cut everything back to 10-15 cm above ground. This looks drastic, but it is correct for perennials.

Your plant overwinters below ground. In March new stems grow from this base.

Timing summary

• May: First pruning - cut top off at 5-10 cm
• June: Second pruning - cut side shoots to 5-10 cm
• July-August: Prevent collapse - only if very heavy
• September-October: Enjoy blooms - do not prune
• October-November: Autumn cutback - cut all to 10-15 cm

Compact growth results

This pruning system results in a plant reaching roughly 60-80 cm instead of 120-150 cm. The plant is also more than twice as full with flowers. The bottom is neatly covered, not bare.

You also get more cut flowers - because each shoot grows and flowers independently, you harvest many loose flower clusters instead of one single stem from the top.

Frequently asked questions

Can I prune only once?

You can. But your plant becomes taller and more prone to falling over. Two prunings (May and June) is really ideal for Aster Novae-Angliae.

What if I cut too hard?

Aster Novae-Angliae tolerates hard pruning well. You can be bold. Your plant recovers fast.

Do I need extra feeding for all this pruning?

A standard spring dose of compost in March is enough. Asters are not heavy feeders. Normal garden soil is fine.

Can I keep pruning the plant short to stay low?

You can. But Aster Novae-Angliae is born to grow big. You get better results with two targeted cuts than constant short pruning.

Does the plant flower less after pruning?

No - actually more! More stems equals more flowers. Your plant blooms much richer thanks to the pruning.

Step-by-step

Step 1: Prune in May when plant is 20-25 cm

May, when your Aster Novae-Angliae is roughly 20-25 cm tall. Cut the top off at 5-10 cm.

Step 2: Prune again in June

June, when the plant has grown another 20-25 cm. Cut each of the four-six side shoots to 5-10 cm.

Step 3: Wait for full plant

Within two weeks after the June cut you will see your plant fill out massively. You now have a full, compact plant.

Step 4: Check in July-August

Check regularly whether the plant stays upright. Only cut if certain stems become too heavy.

Step 5: Let flower in September-October

No more pruning. Let your plant make flowers and enjoy.

Step 6: Cut back in October-November

When frost arrives, cut everything back to 10-15 cm above ground.

Aster novae-angliae varieties

Aster "Alma Potschke": Bright pink flowers, strong grower. Responds very well to pruning. Reaches 80 cm after pruning.

Aster "Purple Dome": Deep purple, more compact by nature. Reaches 60 cm after pruning. Less pruning needed.

Aster "Andenken an Alma Potschke": Bright red, many flowers. Strong branching growth. Ideal for pruning.

Discover your own garden design

At [gardenworld.app](https://gardenworld.app) you can upload your front yard and see how your Aster Novae-Angliae display fits - with realistic height and full form. Plan your autumn palette before you plant.