Immortelle are hardy plants with a high resistance to pests and diseases. Nevertheless, despite good care, these occasionally occur.
Straw flowers, also called helichrysum, are not only very robust, but also easy to care for. With the right care of the helichrysum, you will enjoy the plants not only during the flowering period, but also long afterwards. Finally, straw flowers can be dried and thus used for dried bouquets. Provided that no pests have tampered with it or spread diseases. Because then the decorative flowers can be badly damaged. However, small changes in how you treat the plants are usually enough to breathe new life into them.
Prevention is the be-all and end-all
By taking a few preventive measures, you can prevent your everlasting flowers from being attacked by diseases and pests. For example, always choose a warm and sunny location where hardy specimens can develop. Straw flowers are quite undemanding, but do not like cold and wet conditions. Therefore, keep the plants only moderately moist. Pour small amounts of water onto the surrounding soil, morning and evening, not onto leaves or flowers. The water must not be ice cold. If the helichrysum is in a bucket, you must ensure that the water can drain away freely.
However, these measures do not offer 100% protection. Some of the most common pests and diseases that occasionally afflict helichrysum include downy mildew, Verticillium wilt and aphids.
These diseases and pests can occur
» Downy mildew
Downy mildew is a common plant disease that invades immortelle and then forms a white fungus mat on the underside of the leaves. At the same time, yellow to brownish spots appear on the upper side of the leaves.
Combat:
If you recognize this damage on your straw flowers, remove all affected leaves immediately. As a rule, you do not have to combat downy mildew with chemical pesticides.
Good home remedies for onePlant broths made from stinging nettles (instructions for this here) or field horsetail (instructions for this here) protect against renewed infestation. In addition, it makes sense to thin out dense straw flowers. Downy mildew thrives in humid conditions. With a large distance between the individual plants, the leaves dry off much faster, which then doesn't give powdery mildew a chance.
» Verticillium Wilt
Withered and limp leaves in immortelle are often due to a lack of light, water or nutrients. If you can rule out these causes, your straw flowers may be suffering from the dangerous Verticillium wilt. If the leaves suddenly and seemingly without cause become limp and sallow, this is a warning sign.
Combat:
Remove all affected leaves and observe the plant for a few days. If the wilt occurs again on other leaves, it is best to remove the helichrysum and the surrounding soil. Verticillium wilt is a highly contagious fungal disease. You should accept the loss of a single flower to protect the other plants in your garden. Important: Never compost the infested helichrysum, but dispose of the plant in the household waste. Otherwise you risk the fungus getting back into the garden next year.
» Aphids
Even aphids infest immortelle. Check your plants regularly for aphids. The sooner you spot the pests, the easier it is to fight them.
Combat:
If you only see a few aphids, simply remove them with a dry cloth. In the case of a stronger infestation, it is advisable to spray the plants with a soft soap and alcohol solution. Simply mix 500 milliliters of water with a tablespoon of spirit and a tablespoon of soft soap and spray the plant with it until dripping wet. Don't forget the undersides of the leaves. Repeat the process once a week until the pests have run away.