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How To Keep Your Asters From Getting Leggy

How To Keep Your Asters From Getting Leggy

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Willie Moore
Latest posts by Willie Moore (see all)

Asters are beautiful purple flowers that can look gorgeous in any landscape. However, if you don’t know how to care for them properly, it’s easy for them to become leggy. They can look wild if you let them go for too long, so you’ll want to know what to do.

You can keep your asters from getting leggy by deadheading the flowers, pinching new growth in late spring, and pruning the flowers often. You’ll want to cut back all the stems when the season ends. If you do all this, you’ll have fuller aster plants.

This article will cover what you must do to your asters and when to prevent them from getting leggy. It usually means they just need more care and attention if this happens. Luckily, it’s pretty easy to keep your asters looking their best.

1. Deadhead the Flowers

You must “deadhead” or remove dying flowers from your aster plant. Doing so allows your aster to spend more energy on producing new blooms and leaves, helping it to look fuller. It also stops the plant from releasing seeds, so your garden doesn’t become overrun.

You can deadhead asters anytime during their growing season, so if you see a wilting flower, you should cut it off. However, where you trim the stem can encourage the plant’s growth. You should cut back ¼ inch (6.35 mm) above new growth to encourage the plant to focus energy in that area.

After deadheading or pruning your asters, you’ll want to offer them fertilizer. The plant will put those nutrients towards growing more flowers.

2. Pinch Off New Growth in Late Spring

Next, you’ll want to start pinching back new growth in the late spring. Doing so can slow down growth, reducing how leggy the stems get. You only need to pinch about an inch (25.4 mm) back from the new growth to make the plant fuller and grow new buds.

Pinching asters forces them to grow more across the ground and less straight up. That way, your plant isn’t as leggy and won’t need staking to stay upright.

(PAA) How Do You Keep Asters From Flopping?

The best way to keep your asters from flopping over is to pinch back new growth. This plant has a habit of growing too tall, so controlling how much it grows can drastically improve its appearance. 

It’s also possible that your asters need you to change how often you water them. Both over and underwatering this plant can cause the stems to fall over. Making sure that they have well-draining soil and enough water can help you rule that out as the issue.

Generally, you won’t need to stake your asters until they reach four feet (1.2 m) tall or higher. Pinching them back is the best option to avoid using stakes unless you like the look of tall aster flowers.

3. Prune the Flowers

Pruning asters encourages them to produce more flowers, making the plant look much fuller. This pruning strategy makes any perennial grow more, so it’s suitable for asters. It also can make the plant look much less leggy.

Pruning should be an ongoing process during the growing season. You should start when the aster starts producing flowers and stop at the end of the season. The more often you prune, the less leggy the plant will be.

Here’s how to prune your asters:

  1. Get a nice sharp set of pruning shears.
  2. Sanitize the shears using isopropyl alcohol.
  3. Make sure the plant is dry before you start.
  4. Cut away dead stems and leaves.
  5. Remove overgrown limbs and shape the plant how you want.
  6. Repeat as the season goes on.

You don’t need to remove much of the plant to help reduce legginess and encourage it to grow more flowers. So, you’ll want to be careful not to cut off too much of your plant. 

If you don’t have pruning shears, I recommend trying the VIVOSUN 6.5 Inch Gardening Scissors (link to Amazon). They’re sharp, make precise cuts, and have a secure safety lock. They’re great for deadheading and pruning back asters without damaging the plant.

Here is an excellent video from James Landscaping’s YouTube channel demonstrating the proper trimming process:

How to Trim Asters by James Landscaping, Inc.

4. Cut Back Stems at End of the Season

It’s also a good idea to cut back the aster’s stems at the end of the season. You want to cut them slightly above the earth, so only the stems remain.

This process encourages the plant to grow back the following season. It also stops the plant from dropping seeds, making it easier to keep it from overgrowing. Cutting the stems down also prevents diseases and pests from spreading into the flowers the next growing season.

Overall, cutting back the asters is a great way to prepare your plant for the coming winter.

(PAA) When Should I Cut Back Asters?

You should cut back asters in late fall after they’ve finished producing blooms. You can wait a week or two after it flowers for the last time to ensure it’s done for the season. They should return next year if they were in the ground several weeks before it freezes.

Asters usually bloom during the late summer and fall, so waiting until the late fall to cut them back is more than enough time. Not cutting them back can cause them to multiply drastically next year, allowing them to take over your garden.

5. Have a Fertilizing Routine

Lastly, you must have a fertilizing routine with your asters. Offer them more nutrients after pruning or deadheading them. The plant will make more beautiful blooms and appear fuller.

Most asters must be fed fertilizer twice a month, starting in the spring, right before they bloom. Giving them too much fertilizer can reduce their blooming period, so you should stop feeding them in the late summer.

Having a fertilizing routine is essential for keeping your asters full and blooming. Without one, they can start to look very leggy.


In summary, you can keep your asters from getting leggy by deadheading, pruning, and pinching them. Doing so keeps them lower to the ground so they don’t fall over due to weight. It also helps if you give them fertilizer a few times each month during their growing period.

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