Problems With Ageratum – How To Grow Healthy Ageratums

Problems With Ageratum – How To Grow Healthy Ageratums

By: Mary Ellen Ellis

There are many species of ageratum you can use in the garden. Generally used as annuals, these are also known as floss flowers for their wispy, delicate petals. Height of varieties vary, but most ageratum types grow in low mounds with abundant flowers. They are great in borders, beds, and window boxes and, yet, they do have their problems. Learn how to troubleshoot and manage these to grow healthy, beautiful ageratum flowers.

How to Grow Healthy Ageratums

Ageratum problems can be largely prevented if you grow these plants under the right conditions. They need full sun and will tolerate only very light shade.

The soil should drain very well but remain moist most of the time. The soil should also be fertile and amended with compost, if necessary.

Deadhead spent flowers for more blooms and to reduce disease risk.

Troubleshooting Problems with Ageratum

With the right conditions, this plant is relatively trouble free, but there are some ageratum plant issues that may plague your beds and borders. Know what to look for and how to prevent and manage these problems.

Fungal issues

Fungal diseases such as powdery mildew, gray mold, or Pythium may occur in and cause damage to your ageratum plants. Signs include white growth on leaves and flowers, and damping off of stems at the soil level. Plants may wilt and die.

The best way to manage fungal infections is to use drip irrigation. This prevents the splashing of water and fungal spores onto leaves and stems that overhead watering can cause. Good circulation between plants for air flow is also important and keep mulch from getting too close to the stems.

Insect damage

Ageratum may also suffer damage from insects. Thrips, aphids, and spider mites feed on the leaves. You’ll see silver gray spots at feeding sites or yellow spots on the undersides of leaves. If the infections are bad, the plant will wither and even die.

Aphid feeding may cause leaves to curl. Aphids can also be problematic because they produce honeydew. This can lead to sooty mold infections. To manage these problems, you can try appropriate fungicides or pesticides.

The best way to grow healthy ageratum plants is to provide the right conditions. Weakened plants are more likely to be infested by pests, while poor air circulation and too much water triggers fungal infections.

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How to Grow

How to Grow Salvia

  • Keep weeds under control during the salvia growing season. Weeds compete with plants for water, space and nutrients, so control them by either cultivating often or use a mulch to prevent their germination.
  • Mulches also help retain soil moisture and maintain even soil temperatures. For perennials, an organic mulch of aged bark or shredded leaves lends a natural look to the bed and will improve the soil as it breaks down in time. Always keep mulches off a plant’s stems to prevent possible rot.
  • Careful watering is essential in getting salvia perennials off to a good start. Water thoroughly at least once a week to help new roots grow down deeply. Soil should be damp at about 1 inch below the soil surface. You can check this by sticking your finger in the soil. Water early in the morning to give all leaves enough time to dry. One inch of rain or watering per week is recommended for most perennial plants. You can check to see if you need to add water by using a rain gauge.
  • Until plants become established, some protection from extreme winds and direct, hot sunlight may be necessary. Good air movement is also important.
  • After new growth appears, a light fertilizer may be applied. Keep granular fertilizers away from the plant crown and foliage to avoid burn injury. Use low rates of a slow release fertilizer, as higher rates may encourage root rots.
  • “Deadhead”, remove spent flower heads to encourage continuous flowering and prevent seed development.
  • Remove and discard foliage after a hard frost in fall.
  • In colder regions, apply another layer of mulch (1-2 inches) after the ground freezes in fall. Evergreen boughs (from Christmas trees) provide additional protection. Remove this mulch in the spring.

Troubleshooting Common Problems for Succulents

There are many issues succulents usually run into that might concern you. This article will tackle the most common problems and you'll be well equipped the next time your dear plants are suffering.


  • Upper leaves getting wilted, wrinkled, and crispy dry: Underwatered
  • Older leaves turning yellow, transparent and soggy: Overwatered
  • Brown calloused patches on the leaves: Sunburn
  • Stretches or become leggy with elongated growth: Inadequate light
  • Collapsed, mushy, grey-yellow leaves: Frost
  • Leaves turning red/brown/black, soggy, slimy, with bad odor: Rot
  • Irregular new growth: Pest issue



It’s easy to save an underwatered succulent. Water it thoroughly until the soil is soaked and then let it drain completely. Always use a porous and well-draining soil mix so that it doesn’t hold water for an extended amount of time and lead to root rot. The wrinkled leaves should perk up very quickly just after one or two watering cycles.


Try cutting back on your watering schedule and only water when the soil is completely dry to the touch. If you’re watering your succulents every week and notice signs of overwatering, that means your succulents are not liking it and you should switch to a two-week watering cycle. Also make sure your succulent soil mix is well-drained enough for it to dry out quickly after waterings.

It’s hard to save an overwatered succulent, but there is a chance you can still help it survive by cutting off the top part of the plant and removing any soggy yellow leaves or stems. Allow the cutting to dry out for a few days until the wounds are calloused over and propagate it in new soil. Refrain from watering right after you plant the cutting. Give it a couple days to dry out and get settled in the new soil and you may see new growth appearing in no time.


There’s little you can do when the leaves are sunburned and have turned brown. Simply remove the damaged leaves and adjust the amount of sun exposure your succulent receives. Most succulents prefer full indirect sun, so you can let your plants enjoy the sunlight through a thin curtain or a glass window to block away some harmful UV rays.

Inadequate light

You need to provide more sun exposure for your succulents. But make sure to gradually introduce them to the increased amount of sunlight so they don’t get “shocked” and burned easily. Adjusting from full shade to partial sun and then finally full sun over the course of a few weeks would be your best bet. Remember to rotate the planters every week for even sun exposure and prevent lopsided growth.


Some cold hardy species like Sempervivum can tolerate frost and enjoy cool temperatures from 30 to 40°F, while other tropical species like Euphorbia and Lithops prefer temperatures of at least 50-60°F. Bring your succulents indoors or cover them with frost cloth when the temperature drops below what your plants can tolerate. Prune dead tissue in the spring.


Rot usually starts from the root up, thus when you notice any obvious changes on the plant, there is probably no way to save it. But here are something you can do:

  • Cut off all the rotten parts if the plant has just started to rot in a small specific region. Then let the uninfected part of the plant continue to grow.
  • If possible, cut the stem well above the rotten part and propagate it. Sometimes it might be possible to re-root and grow into a new healthy plant.
  • Avoid planting the body of your succulents so close to the soil to prevent the leaves from picking up some moisture from the soil, leading to rotting leaves.
  • Improve ventilation, do not overwater and avoid leaving your succulents in a cold damp condition. Make sure your soil is porous, well drained and doesn’t hold water for an extended amount of time.

Pest Issue

Inspect your plant carefully to identify any pest issue. Insects are typically not a big problem with succulents. But if there is a pest problem listed in this care guide , follow the instructions there to ameliorate the situation. Most of the time you can treat your infected succulents with a insecticidal soap or mild insecticide.