Hello, hlancast. I hate to answer your question with more questions but it would help to know more.

Does the soil around the base of the plant feels dry, moist or wet when you insert a finger to a depth of 3-4 inches? How much water are the plants receiving and how often? What times of the day do they receive sunlight? Can you describe the way the leaves are changing colors? Are they wilting? Do you notice anything unusual under the leaves? Do you notice any insects eating the leaves? You did not state where do you live so let me ask you if you suffer from weevils in your area?

Most of the sudden problems that I have heard people report are due to nighttime crawlers called weevils, insects that kill the plant in two ways. The larvae feed on the roots while the adult feeds on the leaves. Notched leaf edges are symptoms of weevils. Click here to see an example of notched leaves (scroll down to Figure 3).

Repeated Orthene sprays can be used against the adults but I am not aware of much that can be done to kill the larvae effectively. I seem to remember someone who recommended a sticky product combination where you put a band around the trunk of the plant and then paste some sticky substance to the band so it traps the adults when then try to climb up the plant each day. The band is removed when the problem does away. Click here for more information on weevils.

If this problem has been going on for a couple of weeks and you have not noticed any insect damage then your next possibilities are (1) the azalea was planted with roots that were root bound/pot bound or (2) a fungal disease that attacks the plant roots. Pot bound roots can be seen when you planted the azalea; they would be growing circling the pot. Excessive soil moisture and/or bad drainage are things that contribute to the fungal disease, which may already have been in your soil.

To see if your roots are pot bound, you would have to very carefully check the azaleas roots or you would have to remember if you saw this when planting it.

To see if you have the fungal disease, you would have to very carefully check the roots and see if you see brown, rust or red lessions. The first symptom is wilting of the leaves. Eventually the entire plant dies while the leaves remain attached. You can also manually check to see if the soil feels dry, moist or wet; standing water in the soil contributes to the rapid development of this fungus.

I hope this helps,
Luis

Oh, mea culpa! I just realized that you said that THE FLOWERS, not the plant, was turning brown!!! Ignore what I said above.

Are the flowers getting any spots or do they have a wet look to them? Healthy azalea flowers should last about 1-2 weeks and then will normally turn brown. There is nothing you can do about that. However, if you notice these other symptoms, you have a fungus called azalea petal blight, common during the humid spring months.

To address this problem, remove/dispose of the mulch and other plant debris. Remove and dispose of the spent flowers as well. Then apply this fungicide program recommended by the Azalea Society of America: "Drench soil area under plants with Terracolor in January 2008. Spray with Thylate or Benomyl now & when blooms begin to open in 2008. Continue at 7- to 10-day intervals during bloom period. Good coverage is essential. Bayleton may be used when the buds show color."
For more information on petal blight fungus, please click here.

Sorry for the mix up!
Luis

Here is a link that might be useful: ASA Diseases Webpage

I am looking for what I heard was a new hybrid white azalea that is described as "self cleaning". Normally, the white flowers become wet and brown with age and they tend to stick to the leaves instead of falling to the ground. I love white azaleas and would love them more if the aged petals would fall to the ground. Has anyone heard of such a plant?

Hi,

Don't confuse the behavior of a diseased flower with that of a healthy flower. Azalea petal blight causes flowers to start getting mushy and turn brown before they wilt. A normal flower maintains its color and blooms until it wilts and falls off the plant. One with Ovulinia petal blight starts getting mushy and turns brown while still on the plant.

There are sprays and petal blight can be contained seasons without too much rain. However, most people get a little tricky and know that petal blight builds up slowly during the bloom season. Hence, the plants that bloom first are the least affected. So an early white azalea will have less of a problem. You can further increase your odds by cleaning up all dead flowers after the azaleas finish blooming. The disease is harbored over the winter in dead flower parts.

Sunset climate zone 20 is "Hilltops and Valley Floors of Ocean-influenced Inland Southern California". So I would guess you have a fairly ideal climate with little summer rain but may irrigate. The trick is to keep the irrigation water off the buds and flowers. A wet spring will have more problems than a dry spring.

Here is a classic article on petal blight from UC Davis

Petal Blight of Azaleas

Good luck!