Asters are vibrant flowers that bring color to your garden from late summer to mid-fall. However, they can have some problems, such as browning and drooping. Why does this happen, and what can you do to fix it?
Your asters may be drooping for a few reasons. They might be underwatered, overwatered, or need to be divided. These issues can result in browning and drooping of the flowers, leaves, and stems. Fixes include watering more, watering less, changing the soil, or dividing and replanting.
This article will explore the top three reasons your asters may be drooping, plus offer fixes for each problem. I will also include information about other common problems asters suffer.
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1. They Have Been Overwatered
Watering issues are the number one reason your asters are drooping. Asters are drought resistant, so they don’t need a lot of water and can go quite a while between waterings. As such, overwatering is the most common problem for asters, as it can lead to root rot.
Root rot is a bacterial infection of the roots due to excess moisture. When a plant sits in wet soil for too long, the roots begin to rot away, preventing the plant from taking up water and nutrients (source).
Root rot symptoms include:
- Drooping leaves and flowers.
- Yellowing and browning.
- A foul smell near the base of the plant.
- Rotting of the stem just above the soil line.
For more information see our guide What Are The Signs Of Overwatering Plants?
How To Fix
Identifying root rot as the cause of drooping is tricky, as the proof can often only be found when the plant is uprooted. However, if you suspect your asters have been overwatered, it’s best to treat them as though they do have root rot.
There are a few things you can do:
- Stop watering and wait for the soil to dry out.
- Aerate the soil around your asters to encourage it to dry out faster. You can do this by poking it with a stick or tilling it with your hands.
- Mix inorganic materials into the soil to improve water drainage.
Inorganic soil additives include:
- Volcanic rock
If you try all the items on the list above and your asters don’t improve within a week or so, your last ditch effort to save them is to uproot the plants and treat the root rot directly.
Follow these steps:
- Gently uproot the plant. Do your best not to damage any healthy roots that remain, as the plant will need these to recover.
- Wash the roots with clean water. As you do, note any roots that look brown, black, mushy, and/or smell foul. Healthy roots will be firm and pale.
- Remove the infected roots. Be thorough about this! Any root rot left behind may spread and re-infect the remaining healthy roots.
- Dispose of the soil the plant was growing in. It is also infected with root rot and will reinfect the plant (or any other plant you put in it).
- Optional: Dip the roots in hydrogen peroxide for 1-2 minutes to kill off any remaining root rot residue. Alternatively, you can water the replanted aster with a 1:1 solution of hydrogen peroxide and water.
- Repot or replant the aster in a fresh, fast-draining soil mix. Combine regular potting soil with the inorganic material of your choice. Use a 3:1 ratio for best results (3 parts soil to one part inorganic material).
2. They Have Been Underwatered
As with overwatering, underwatering also causes drooping. Though asters are relatively tolerant to drought, underwatering can occur, especially if:
- You tend to forget to water.
- You go on a summer vacation and don’t arrange for a gardener.
- You live in a location with a particularly hot, dry climate.
- The soil is sandy or otherwise very fast-draining (i.e., it contains too much inorganic material).
When underwatering occurs, it frequently results in the following:
- Browning of leaves and stems
- Leaves dropping off the plant
- Wilting/drooping of flowers
How To Fix
First of all, if you’ve underwatered your asters, don’t overcorrect! If you give them too much water to compensate for the drought, you may end up with the opposite problem (i.e., root rot).
To treat drought, you can do a few things:
- Water normally.
- If there is a heat wave, give your asters an extra inch or a few centimeters of water each week.
- Mix some water-retaining materials into the soil.
Changing the soil composition can help you to avoid underwatering in the long term, especially if you live in a hot, dry climate or you tend to forget to water. Aim for a ratio of 1:4 (one part moisture-retaining additive to 4 parts soil).
Moisture-retaining materials to add:
- Coco choir
- Peat moss
3. They Need To Be Divided
While watering issues are more common, an aster that has grown a lot and needs to be divided may also exhibit drooping. However, this drooping will look a little different.
The following are symptoms your aster needs to be divided:
- There is little foliage near the bottom of the plant.
- Drooping takes a circular pattern with the stems falling outward, away from the middle.
- The middle of the plant looks dead.
Luckily, this is a sign of a mature aster that has essentially reproduced until the new growth has begun to strangle the old growth at the center.
How To Fix
Divide your asters! These plants are perennials and need to be divided every 2 to 3 years. Division should happen at the beginning of the growing season, in early spring (or whenever the weather starts to warm significantly in your area).
Follow these steps to divide asters:
- Gently dig up the plant. Be careful not to harm the roots too much, as too much root damage will shock the plant and cause it to have a longer, slower recovery.
- Optional: Rinse the excess dirt away from the roots, so it’s easier to see them.
- Using a (sanitized) sharp knife or shears, cut through the center of the root ball. Do your best to ensure that there are about equal plant stalks and root volume on each side of the cut.
- Repot or replant each half of the aster. Use fresh soil, and ensure the mixture is appropriately fast-draining or water-retaining per your needs and the directions above.
Drooping asters can be caused by root rot, incorrect watering, and the need for division. Fortunately, the solutions are relatively easy and straightforward. You can bring your asters back to their beautiful, healthy state by removing rotten roots, following the correct watering schedule, and dividing them every few years.
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