Gerbera daisies, with the scientific name Gerbera jamesonii, belong to the Asteraceae family and are native to regions of South America, Africa and Asia. These plants are also called African daisies and Transvaal daisies, and their flowers feature double-lipped ray florets in orange, white, yellow, pink or red. Most of these tender perennials bloom all year round, but like most plants also suffer from conditions that cause yellowing leaves.
Gerbera Daisy Leaves Turning Yellow: What Are The Reasons?
Lack of nutrients in the soil
The leaves of gerbera daisy plants tend to turn yellow if they lack nutrients such as nitrogen and magnesium. To fix this, feed your gerbera daisies with an organic fertilizer that has a high nitrogen content, at least twice yearly. Ideally, you should fertilize in the spring and fall.
Magnesium deficiency also causes leaves to turn yellow around the edges, leaving arrow-shaped green centers. Apply Epsom solution to your gerbera daisies once a week: this is about an ounce of Epsom salt mixed with five gallons of water.
Iron is essential for the production of chlorophyll, the green pigment in leaves, and if iron is lacking due to incorrect soil pH, this could also lead to yellowing leaves. In this case, the veins of the leaves will remain green. To fix the problem, spray the foliage with chelated iron and opt for a more acidic fertilizer, such as a 20-10-20.
Overwatering
Gerbera daisy leaves may turn yellow due to overwatering, or too much water in the soil. Too much water could result in root rot, and nutrients will not be absorbed from the soil. This can weaken the plants and result in leaves turning yellow, brown or red.
Make sure your planters have drainage holes so that excess water can easily flow out. If the daisies are planted in the ground, see to it that you have a well-draining soil mix to ensure there is no trapped moisture in the soil.
Fungal diseases and other infections
Another reason gerbera daisy leaves may turn yellow is fungal infections like powdery mildew. This disease usually thrives in areas where plants are overcrowded. To fix the problem, use a fungicide on the foliage. Plant your plants in sunnier spots and prune those in overcrowded areas to increase air circulation and reduce relative humidity.
Root fungus could also infect the plants, resulting in root decay and wilting, yellow leaves. To diagnose this, you will have to dig up the entire plant and examine its roots. Root fungus indicates overwatering or poor drainage.
Aside from fungal diseases, viral infections could also affect your gerbera daisies. You will know it is a viral infection if you notice mottled leaves with yellow spots, dead flecks, and line or ring spot patterns.
Other diseases that could infect your gerbera daisies include the following:
- Rhizoctonia crown rot – This disease is characterized by brown lesions on the stem, and infected plants will wilt and die as the infection becomes severe.
- Pythium root rot – The plants will wilt and die as the roots rot.
- Alternaria leaf spot – This disease is characterized by brown specks on the florets and the leaves.
- Bacterial leaf spot – This disease is characterized by small spots that become irregular and dark brown to black.
Gerbera Daisy: Care Tips
Be sure to use the right soil or potting mix.
Gerbera daisies thrive in average to rich soils and medium moisture conditions. The soil should be well-draining to avoid stem or root rot. Ideally, you should plant the daisies in containers or raised planting beds, especially if the soil is not well-draining. Enrich the soil with organic matter to aid healthy growth.
Gerbera daisies prefer soil pH levels of 6.1 to 7.5. If the soil is more acidic, add a bit of dolomite limestone. This neutralizes the soil acidity, improves soil texture and allows the plants to better absorb nutrients from the soil mix.
Water the plants properly.
Gerbera daisies grown outdoors should be given deep watering at least once a week, or whenever the top inch of soil becomes dry. Young plants may need to be watered more frequently, especially during hot weather. Indoor gerbera daisies need to be watered every three to five days; be sure to water at the base so the leaves stay dry. Empty the water that becomes stagnant in the drip tray and reduce watering during winter, but be sure to check that the soil does not dry out completely.
Be diligent when it comes to applying fertilizers.
Feed your gerbera daisies with controlled-release fertilizers at least two to three times during the growing season and liquid fertilizer at least every two weeks. A complete fertilizer application is ideal once a month. Use a foliar fertilizer that is high in iron and manganese, and spray this on the foliage.
Deadhead spent flower stalks to encourage the plants to rebloom.
Gerbera daisies may stop blooming for about two weeks and take a break before they start to bloom again. The flowers stay in bloom for at least a few weeks, and to encourage them to rebloom you should deadhead the spent flower stalks regularly with sterilized shears. Trim the large center leaves to allow light to reach the center and to encourage new bud growth.
Expose the plants to at least six hours of direct sunlight daily.
Gerbera daisies like to soak up the sun, especially during cold weather. Place the plants in an area where there is direct sunlight for at least six hours a day. During hot weather, place your plants in a spot with light shade.
Overwinter the plants.
Overwintering is the process of organisms waiting out the winter season, or passing through a period of the year when conditions make normal activity difficult. Ideally, you should winterize the plants for a few weeks in late September by digging them out of the garden and pruning the remaining flowers. Remove most of the soil and cut back some roots. Repot the daisies in new pots with a fresh potting mix, taking care not to plant them too deep in the soil.
Conclusion
Yellowing gerbera daisy leaves could be attributed to a lack of nutrients in the soil, such as nitrogen and magnesium. These tender perennials could also suffer from yellowing leaves due to overwatering, or due to fungal and bacterial diseases such as powdery mildew or root rot.
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