| You mention yellow leaves, but that may indicate many different problems. Check these: Yellow leaves with green veins indicate a nutrition problem with not enough iron. It is usually caused by a high pH but can also be caused by poor drainage, planting too deeply, heavy soil with poor aeration, insect or fungus damage in the root zone and lack of moisture. Small yellow leaves and stunted growth are signs of water stress brought on by water-logged soil or wet/dry fluctuations in soil moisture. Yellow mottling on the upper surface of leaves and black sooty mold and transparent insects on the bottom are symptoms of Azalea Whitefly (Pealius azaleae.) and Rhododendron Whitefly (Dialeurodes chittendeni.). Yellowing of leaves surfaces, often with brownish burned areas, occurring on leaves that are more exposed to sun, is caused by more sun exposure than the plant is able to tolerate. Some varieties need shade, while all plants that have been protected from direct sun will be tender until hardened off by gradual exposure to sun light. Possible solutions are to give the plant more shade or move it to a more protected site. Uniformly yellowish-green leaves is often just the need for more nitrogen. This will be more noticeable in the full sun. Some less sun tolerant varieties will always be light green in full sun. Yellowing of leaf edges has been noted in gardens where sandy soil conditions or root competition with other plants caused insufficient soil moisture and nutrients. Usually incorporating organic material in the soil and removing the plants with the competing roots solved the problem. Care must be taken not to disturb the roots of the rhododendrons and azaleas. Hence it is best to prepare the soil adequately before planting. The tops of most competing plants can be removed leaving the offending roots in the ground and the offending roots will simply decay and pose no problem. |