Rose (Rosa spp.) and hybrids-Lime-induced Chlorosis

Cause Lime-induced chlorosis, or leaf yellowing, is caused by alkaline soil conditions. High (pH) alkalinity of soils can make iron or manganese unavailable to plants, causing leaf chlorosis. Has been more common in samples from eastern Oregon. Ideal pH for growing roses is from 6.0 to 6.5.

Symptoms The initial symptom is an interveinal chlorosis of the young leaves with the main veins remaining green. These leaves may remain small and become pale yellow to white.

Cultural control

  • Reduce soil pH by adding sulfur or organic matter, especially conifer needle mulch, which is highly acidic.
  • Check plant's proximity to newly poured concrete. New concrete leaches lime into the surrounding soil, raising the pH.
  • Use iron chelate, either as a soil treatment or by foliar feeding, to help chlorotic plants quickly. Read and follow all label instructions.

Reference Voogt, W. and Sonneveld, C. 2007. The effects of Fe-chelate type and pH on substrate grown roses. In International Symposium on Growing Media. 819:411-418.