Daffodil leaves always turn yellow a few weeks after the plant blooms. This is normal and indicates that their job is finished for the season. The leaves have absorbed sunlight, which creates energy for the production of sugar that replenishes the bulb for the coming growing season. Daffodils with yellow leaves at any other time, however, may indicate a problem, often caused by disease. Read on to learn more.
Reasons for Daffodil Leaves Turning Yellow
If your daffodil leaves are turning yellow because of disease, then you may need to destroy the bulbs and start fresh with new, disease-resistant bulbs. Look for bulbs that have been pre-treated with fungicide. Below are the most common issues leading to yellowing daffodil foliage.
Basal rot is a serious fungal disease that survives in the soil and becomes active when soil temperatures reach about 55 degrees F. (12 C.) in spring. The disease is becoming more widespread with high temperatures and increasingly warm summers.
Basal rot is indicated by daffodil leaves turning yellow much earlier than expected. A bulb infected with the disease will be dried up or decayed, and may display a brown or brownish-purple rot that grows from the bottom of the bulb.
Diseased bulbs should be removed and destroyed as soon as possible to prevent spread of disease, then dig and treat remaining bulbs as soon as possible. Fungicide will not save diseased bulbs, but it may prevent the disease in nearby, healthy bulbs.
If daffodil foliage turns yellow on the edges and the leaf tips display yellow or reddish-brown lesions, the plant may have a fungal disease known as leaf scorch. Soon, the lesions merge together and the yellowing leaves turn brown and die. This disease is most prominent when summer weather is mild and moist.
If you notice spots on the leaf tips, you may be able to prevent the disease from spreading by trimming the affected plant parts. If the disease is severe, it’s best to dig and discard the bulbs as soon as possible. It’s also important to rake and discard leaves and plant debris in the area around the plant. To prevent spread of this disease, never place diseased plant parts in your compost pile.
Yellow Stripe Virus
Yellowing leaves on daffodils may be the result of a yellow stripe virus, especially if the leaves and stalks display yellow streaks and spots soon after they emerge. Affected leaves may also be distorted.
If you think your daffodils have yellow stripe virus, the best recourse is to destroy the infected bulbs. Control pests carefully; plant viruses are often spread by aphids or nematodes that live in the soil.
Root rot is a common reason for stunted, withered or yellow daffodil leaves. This fungal disease is more common on bulbs that have been in place for several years. This disease doesn’t affect the bulbs and is usually not deadly. It is often caused by planting too deeply or in wet, poorly drained soil.