Why is My Alyssum Dying? Reasons and Preventions

Alyssum is a low-growing, flowering plant that is typically used as a border plant in garden beds. They have tiny pink or white flowers that bring life to the garden. So if your Alyssum is dying, you would be looking for reasons to save the plant.

Reasons for Alyssum Dying include Cold or frost, Poor drainage, Inadequate care, Excessive shade, Diseases, Incompatible soil, and Pests.

Tread carefully while caring for your alyssum as not all these issues can be solved in time! 

There is no one reason but many reasons why your alyssum could be dying! Some of them are ones from which you cannot save the plant. So, the next best option is to prevent the whole situation.  

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Common Reasons for Alyssum dying

Let us look at possible reasons why your Alyssum might be dying with ways to solve.

1) Alyssum Dying due to Cold or Frost 

Very cold to freezing temperatures can cause a decrease in plant enzyme activity, disrupting the plant’s nutrient intake. Which leads to stunting or worse, death!

Water that freezes inside the plant’s cells will expand from within and cause the plant to wilt and die.

Additionally, wet weather may lead to fungal diseases, like root rot and crown rot. Too much rain followed by cold weather can leave an excess of moisture sitting in the crown and around the roots.

Without the sun to evaporate the moisture, the plant cannot rid itself of the excess water. The roots therefore rot, and so does the crown, as it holds water too.

How to Prevent Cold or Frost in Alyssum?

Most Alyssum plants are nursery-grown. They are acclimated to the greenhouse being warm and humid.

Therefore they are unable to adapt to cold or freezing temperatures. If you don’t have pleasantly sunny conditions for most of the year, you may want to choose to grow a different plant.

Otherwise, if the only cold weather occurs in winter, you can grow your alyssum in a pot and bring it indoors. 

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2) Poor Drainage / Overwatering

Coastal flowers like alyssum thrive in porous well-draining soil, which is more stone/gravel than soil. Ultimately, it is best to grow them in organic well-draining soils. 

Alyssum plants that are container grown need a well-draining medium and the pot must have drainage holes at the bottom.

Using boggy or clay-rich soils will result in your alyssum dying, especially if watering habits are not in-line with the watering routine in place! 

How to Prevent Overwatering in Alyssum?

With this plant, you can’t really make the mistake of killing them with excessive water. Alyssum has very lax soil requirements and grows in a range of soils as long as they are well-draining. 

Also, you only have to provide more watering in the hot summer months. Otherwise during regular weather, an inch of water a week is adequate to quench their thirst. Don’t make your alyssum go too long without water as this causes them to die! 

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3) Inadequate Care Before Establishment

You’ll find your newly bought alyssum dying and not growing if you do not give it adequate care initially post your purchase. In the first few weeks that the plant has been planted and repotted, careful watering is of great importance. 

If they are not watered regularly they will die as a result of shock and not becoming established fast enough. Remember small plants have even smaller and more delicate root systems and this calls for more care and attention. 

How to Prevent It?

Definitely keep a close eye on the plant. If you are watering it but it is still not establishing itself, more watering may be necessary. You can either water it a little bit every day or you can provide a large amount of water at a time. Do as your alyssum deems fit!

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4) Alyssum Dying Due to Too much shade

Complete shade is inadequate for a plant like Alyssum. Just because they don’t do their best in full sun for the whole day doesn’t mean they love the shade.

In fact, too much sun or too little shade can kill it! But, the excessive sun is not the only reason why alyssum in shade dies.

If you plant them under a tree or in the shade of a large building, alyssum may be susceptible to stem rot or leaf blight. When they are grown on very wet land, they are prone to Botrytis blight. 

How to Prevent It?

Partial sun containing a moderate time in the sun and the rest in partial shade will be most acceptable. This way, the plant gets more than enough photosynthetic time while it is sheltered for the rest of the time. 

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5) Too Much Sun

These plants are not sun-loving plants. They could be receiving more sun than they can handle which may be a reason why they are dying! 

Alyssum plants need 6-8 hours of sunlight but in hot climates, fewer hours of intense sun will do. Giving them a lot more than this can result in excessive loss of water from the plant and wilting. 

Although more sun can result in more flowering, the positives don’t outweigh the negatives. 

How to Prevent It?

Giving your alyssum partial shade is the best option to keep it alive and happy! The excessively hot sun can scorch the plants. Watering generously during such times would be great for the plants and so would provide them with shade. 

Alternatively, planting them in pots would provide the ability to move the plants out of the sun’s path. 

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6) Diseases and Small Pests

Like most plants, alyssum also comes with quite an assortment of possible diseases it may face. 

– Clubroot

Plant symptoms include yellowing of leaves and the plant may wilt. Upon removal from the earth, the plant’s roots are swollen and show distortion. Clubroot is at its worst in poorly drained soil, with acid to neutral soils. 

Soil contamination occurs through a number of factors such as diseased plants, manure, soil on shoes, equipment, or crop refuse. The pathogen can remain in the soil for 10 years or more.

– Downy mildew

This mildew presents itself as a whitish-gray patch, initially on the underside of the leaf, but then covers both sides of the leaf. 

Downy mildew is caused by the fungus Oomycetes. This organism becomes a problem during the cool, humid weather attacking the plant above ground.

The down-like tufts at the underside of the leaf are actually spores that are easily dislodged by water or wind.

– Fasciation

Fasciation is when the tip of the plant becomes genetically mutated. It can affect the plant visually, changing the appearance of leaves, fruit, or even flowers. Instead of expecting one flower, there could be many. 

This condition also affects the quality of the flowers, they could be misshapen and flattened in a way that is visually unappealing. Sometimes the stems become flat and give the appearance of fusion.

Many times you may notice the shoots are flat and the flowers are not so shapely. These are sure signs of fasciation in alyssum plants.

– Aphids

These pestering insects need no introduction, everyone knows them. Hoards of tiny green insects on stems or nodes indicate a severe aphid infestation on your alyssum plants. They have natural predators but you may have 

– Cyclamen Mite

The mites settle on and under leaves and petals and suck sap from the plant. The only obvious sign will be curling on leaves since these insects are only visible under magnification.

Even then they appear as oval-shaped spiders. 

How to Prevent It?

The best way to prevent diseases in alyssum is to buy quality plants/seeds, inspect them regularly, and adopt hygienic practices.

Also, providing quality soil, fertilizer, and water will result in a healthy plant and will not further compromise the plant.

In the case of aphids, you should try to hose the aphids away initially to reduce numbers and make it easier to treat. Apply Neem oil or insecticidal soap on infected or disease-prone areas of the plant.

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7) Soil Characteristics are Incompatible

The quality of soil you use to grow alyssum matters most because the plant will remain with this soil, So, really bad soil could be the reason for your alyssum dying! 

Soil characteristics include more than just soil fertility and drainage capacity. It involves pH and general quality. Remember, alyssum can even end up sprouting out between two rocks if it wants to. 

How to Prevent It?

It cannot be stressed enough that alyssum needs well-draining soil. While fertility is not much of a concern, soil pH must be neutral to acidic. 

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8) Damage Due to Larger Animals

We’ve already covered insect pests but what about larger pests? No one really considers them, but they can be a problem occasionally. Most alyssum plants aren’t toxic to dogs and cats and so you could find them destroying your plants.

And although deer don’t necessarily eat alyssum, they could become damaged if trampled through by these big animals. If the damage is major, your alyssum could end up dying and not recovering. 

How to Prevent It?

If you notice a larger pest damaging your plants, plant them in a pot and bring them indoors. Or else, you could fence them off and put them somewhere where they can’t be reached. 

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Most common reasons for alyssum dying are:

  1. Cold or frost 
  2. Poor drainage
  3. Inadequate care
  4. Too much shade
  5. Excessive shade
  6. Diseases and small pests
  7. Incompatible soil
  8. Animals

It’s definitely a good idea to observe your alyssum plants regularly, provide the right environment and care, and prevent them from dying in the first place!

What are the most prominent Alyssum problems when growing?

Botrytis/leaf blight and stem or root rot are the biggest alyssum problems you will encounter when growing these plants.

Both conditions occur when you grow alyssum in too much shade and they do not have enough sunlight to dry the soil. Also, it may occur if plants are too close to each other and there is poor ventilation.