What Causes Buttercup Leaves to Yellow?

End of Season

• Buttercups prefer to grow in moist but well-drained soil in areas with partial shade or full sun. Flowers bloom from late winter to summer depending on species and local climate. Once the buttercups have finished blooming for the year, the leaves of the plant will naturally turn yellow. Do not cut back buttercup leaves as they begin to turn yellow at the end of the growing season; instead, wait until they die back naturally to remove them. The plants continue to need water and light even after blooming has stopped for the season because the leaves are still working to store energy for the following year.

Moisture Variances

• Extreme variances in soil moisture that stress the plant can also cause the leaves on buttercups to yellow. Excessive watering or too much rain, particularly during long periods of warm weather, can cause diseases like crown rot to plague your buttercups. Crown rot results from infection of the plant by the fungus Sclerotium rolfsii, which attacks the base of the plant. Crown rot causes the lower leaves to wilt and turn yellow first and then moves along the plant stem, killing the upper leaves. As with many ornamental plants, over watering buttercups during an extended drought can damage the leaves, turning them yellow. During a drought, the leaves contract, allowing for less evaporation of moisture. Water sparingly during periods of little rainfall; a sudden infusion of a significant amount of moisture can stress the plant, encouraging it to begin dropping leaves.

Disease Transmission

• Disease is another potential reason for the yellowing of leaves on buttercups. The plants are susceptible to diseases that are carried by pests, including thrips. Both tomato spotted wilt and impatiens necrotic spot viruses can infect buttercup plants even when they are in greenhouses. Plants with these diseases may display symptoms such as wilting, stunted growth, and yellow spots or streaking on the leaves. Thrips are small, thin insects that suck the juices from a plant’s leaves or stem; in the process of feeding, they transmit the diseases from one plant to another.

Need for Nitrogen

• Buttercups need a steady supply of nitrogen to get them through bloom time with healthy, dark-green leaves. A lack of nitrogen is another potential problem that can cause plant leaves to turn yellow and stunt the growth of your buttercups. The largest and oldest leaves on buttercups will start to show damage from a nitrogen deficiency first, eventually dying and dropping off the plant. A plant’s uptake of nitrogen can be affected by too much phosphorus in the soil. Ensure that your planting soil has a proper balance of nutrients for buttercups.