Dead Heading: Breaking off nearly spent flowers is a good practice to keep flower diseases from becoming a problem. Simply snap off the old flower at the base of where the flower starts. (yes, it can be an overwhelming task).
Note that if you do not Dead-Head, the seeds pods will stay in tact and you will potentially have to wait an additional year before the branch blooms again. Deadheading enables (helps insure) your rhododendron to consistently bloom annually.
Phytophthora: Phytophthora cinnamomi. It occurs when plants are not planted correctly in well-drained soil. There are two forms to worry about. Phytophora Leaf Blight is where the stem will get black and quickly wilt, then die! This should be cut off and destroyed. (Burning is ideal)
The second form is Phytophthora Root Rot occuring within the root zone. This kills the plant quickly and usually shows itself in early spring by way of a wilted (cold-look). Pull the plant from it's location and burn. South Eastern Climates have great difficulty with this specific issue. It might be a good idea to remove the surrounding soil and replace with new soil in extreme or continuous circumstances.
Root Weevil: Root weevil are one of the most frustrating and damaging pests. They hurt the plants in 3 ways:
Notching not only looks bad but makes the plant susceptible to foliage diseases.
Root weevil larvae eat the roots and girdle the base of trunk, killing the plant from beneath the soil.
Root weevil larvae eat enough of the roots to compromise the plant's health to being susceptible to Phytophthora, ultimately killing the plant under stress.
Root weevil Larvae visual look of root weevil (larvae) damage: As you can see here, the plant looks unhealthy. Light green, wilted leaves that look chloractic. As illustrated, this plant has fed numerous weevil and the result was a complete girdling of the plant's root stem base. This plant is dead!
As you can see here, the plant's root system has been nearly completely destroyed and turned into a mushy, silt-like soil texture. You can try to recover a plant like this but your best option is usually to take cuttings and hope to continue it's life through cloning (cuttings).
Adult Root weevil: (Adult Root weevil notching) As you can see in this photo, the Adult Root weevil comes out at night and eats the foliage by way of notching here and there until the plant looks like it has been through a hail storm. This does not necessarily mean that larvae are within the roots but rather there might have been earlier.
Seed Production: These two photos to your right illustrate how Rhododendrons regenerate. By deadheading these in the summer, you will have a flower bud or new growth at the minimum instead of these rather ugly seed pods.
See the tiny nodes just before the flower stem. There are two in this photo that will explode with new growth.
If this would have been deadheaded, these would have been full size stem shoots.
Each Seed pod holds approximately 300 seeds and a whole flower may produce 3-5,000 individual tiny seeds.
They open up like slices of oranges between September and December depending on the variety and your climate. If your looking to grow some seedlings, please see American Rhododendron Societies web site
Sun Burn: Some days are like no others and will burn plants foliage. There is nothing to do other than move the plant in filtered light.
The worst case scenario is where plants are in the shade all day except for the hottest part of the day being in full sun. Provide a scenario whereby plants get full sun in the early morning and again in the evening. Filtered shade in the afternoon is optimal.
Winter Burn: Winter burn looks similar to that of Sun Burn. For all practical purposes, it is nearly the same. The only thing you can do in this instance is protect plants with a shade cloth over them in the winter protecting the plants from sun while the roots are frozen. Another way is to look for cold hardier varieties. Another way is to pass it off as a unique year and live with it, hoping next year will not be the same. This plant was left and is doing fine. We chalked it up to a unique scenario.
Bud Blast: Bud blast may occur for many unknown reasons but usually occurs when plants are subjected to cold weather after they had begun swelling.
