by johnah on November 25, 2020
Yellow Rhododendron Leaves: Why Are They Turning Yellow?
Rhododendrons are one of the most popular plants in gardens. However, it’s not just their beauty that makes them so popular; they’re also known for having some pretty spectacular flowers! These flowers are called “rhododendrons” because they have bright red or pink petals that resemble roses. Although these flowers look lovely, they can sometimes become unattractive if left unsupervised. For example, when temperatures get too hot, the petal color fades and the flower becomes less attractive to birds and other animals.
Another problem with these beautiful flowers is that they’re susceptible to damage from insects such as aphids and scale insects. Aphids feed on the plant’s sap, which causes the leaves to turn yellow.
Scale insects cause the leaf veins to shrivel up and eventually die off completely. Both of these problems can make your garden look worse than it already was!
The reason why these two pests are able to cause such drastic changes in a plant’s appearance is due to their ability to manipulate certain chemicals within a plant’s tissues. For example, when aphids feed on a plant, they inject a substance called “hormone-like” (which is very similar to certain plant hormones).
This substance slows down the development of leafy parts within the plant and this is why the leaves turn yellow or brown and start dying.
This process can be reversed quite easily by simply removing the insects themselves.
Sources & references used in this article:
… , TINGITIDAE), THE RHODODENDRON LACEBUG: FEEDING HABITS AND THE HISTOLOGY OF THE FEEDING LESIONS PRODUCED IN RHODODENDRON LEAVES by CG Johnson – Annals of Applied Biology, 1937 – Wiley Online Library
THE BIOLOGICAL ACT’IVITIES OF YELLOW AZALEA, RHODODENDRON MOLLE G. DON AGAINST THE VEGETABLE LEAFMINER, LIRIOMYZA SATIVAE … by HU Mei‐ying, Z Guo‐hua, WU Qi‐song… – Insect …, 2000 – Wiley Online Library
Deficiency symptoms of Rhododendron studied by CR Johnson, AN Roberts – Ore. Orn. and Nurs. Dig, 1969 – agsci.oregonstate.edu