Why Are the Lower Leaves of Poppies Browning?

Poppy Viruses

• Poppies are susceptible to tomato spotted wilt virus, a disease spread primarily by western flower thrips. Symptoms may include brown rings or necrotic spots on leaves, wilted leaves, or stunted growth. The virus cannot be cured: infected plants must be dug up and destroyed, according to Colorado State University. Help prevent viruses by removing nearby weeds, which can host viruses and pests, and avoiding broad-spectrum pesticides, which kill beneficial predators. Inspect new plants to ensure that they have no signs of the virus.

Those Rotten Poppies

• Root, stem and crown rots may all infect poppies. Symptoms start as dull, wilted foliage. Stems and roots may also turn dark and rotten. Seedlings may not emerge, as seeds have rotted in the soil. The University of California Statewide Integrated Pest Management Program recommends digging up and destroying infected plants. Poppies require very well-draining soil and prefer conditions on the drier side. They often do not need supplemental watering, except during extended periods of drought.

For Your Consideration

• Poppies such as Oriental poppies (Papaver orientale) go dormant in the summer, according to the National Gardening Association. This is a completely normal process in which the plant turns brown, shrivels up and appears to die. Mark the area where the plant is located so you don't accidentally dig it up or plant over it. The plant will sprout new leaves in the fall and will generally flower again in the spring. Cease watering or water sparingly during dormancy to avoid rotting the roots.

Prevention Tips

• You can help prevent foliage problems by following proper cultural guidelines. Space poppies adequately to ensure good air circulation: about 2 to 4 feet, depending on the size of the species. Poppies generally require a sunny site. Only plant poppies where hardy. Oriental poppy thrives in U.S. Department of Agriculture plant hardiness zones 2 to 7, while arctic poppy may be grown in USDA zones 2 to 8. The California poppy prefers the warmer temperatures of USDA zones 8 to 10. If you irrigate during a dry stretch, keep water off foliage, as wet foliage invites fungus.