One of the most common causes of necrotic (dead) leaf tips and margins is over-watering. The mechanism by which this occurs arises from the fact that soggy soil reduces the oxygen essential to root function and metabolism, so roots are not efficient enough to move water to the plant's most distal parts - leaf tips and margins. The TWO most common causes of poor foliage are over-watering and a high level of solubles (salts from fertilizer and tap water) in the soil. Both of these maladies are exacerbated by heavy soils that are watered in sips to prevent root rot. Sunburn shows up as grey or silver areas on the foliage as the chlorophyll is bleached (oxidized) by the same free oxygen radicals found in hydrogen peroxide, also a powerful bleach/oxidizer. Following the short period of gray/silver blotches, foliage will turn brown, or sometimes black in plants with succulent foliage. 'Red' isn't in the realm of possibility because these oxidants would destroy the pigments that cause red coloration in plants. I use soils that require very frequent watering - usually daily in the summer months, and I can't remember the last time I had a plant with poor looking foliage. Fast soils allow me to water copiously and flush accumulating salts from the soil each time I water w/o any concern about root rot or suppressing root function because of soggy soil. I can also fertilize frequently at reduced rates with no worries about the level of soluble salts in the soil interfering with water and nutrient uptake. I wouldn't put much faith in the idea that letting your water rest for 24 hours is going to play a significant role in correcting your foliage issues - it won't. It's possible that chlorine (an element necessary for normal plant growth) and fluoride might be marginally contributory to your issues, but the fluoride in drinking water isn't volatile (doesn't dissipate) and nearly all municipal water suppliers are using a non-volatile form of chlorine as well. Almost all causes spoiled foliage issues can be found within the triangle formed by soil choice, watering habits, and nutrition. Unless your plants are next to a heat source (register/radiator, under hot lights, on top of a TV .....), most other cultural conditions like low humidity, chlorine, fluoride .... will be marginally contributory. Most growers take a giant step forward in their ability to produce consistently healthy plants with the least amount of effort once they've come to understand the importance of soil choice to their success. Getting your plants into a healthy, fast draining soil that holds little or no excess water provides a foundation you can build strong plants on. Heavy soils that support excess volumes of water are inherently wrought with issues that find you fighting the soil constantly instead of letting the soil work FOR you. More on that if you wish. I would abandon the use of any fertilizer for plants in containers that have the middle number (phosphorous) higher than either the first or third numbers (nitrogen and potassium respectively). No plant uses more P than either N or K, so it makes no sense to supply it in excess because an excess is limiting. When all the calculations are done, fertilizers in the 3:1:2 RATIO (RATIO is different than NPK %s) come closest to providing nutrients in the ratio plants actually use. This is very important when growing plants with temperamental foliage because it allows you to supply nutrients at the lowest level possible w/o nutritional deficiencies. LOW levels of soluble salts in the soil greatly increase your chances of producing plants with healthy leaves. Questions? Al

When you planted the azaleas, did you loosen the rootball well so roots could reach out and begin to establish into the surrounding soil? If they are planted from containers with the rootball intact in its pot shape, it can be very hard to wet the potting medium again once it dries out...the soil immediately around the plant can be moist but not the roots themselves. You don't say what form of fertilizer you are using 'once a month'. Azaleas and rhododendrons have low nutritional needs compared to many shrubs, it's easy to burn their fine surface roots, or damage them scratching in a granular type fertilizer.

The white areas of the leaf on the far left may be nothing more than a newly developing leaf that has yet to develop the green color. It's also possible that it is the beginning of one or more leaf galls. These are swollen, puffy areas on the leaves which remain pale and nearly white. Just cut them off and dispose. The middle picture shows some sort of leaf spotting. There are a number of fungi which can cause this. Usually it is unsightly but not a fatal condition. "Blight" in azaleas and rhododendrons usually refers to ovulinia petal blight. It effects the flowers, not the leaves. The third leaf shows lace bug damage. I have had very good results from using Bayer Advanced Azalea, Camellia and Rhododendron Insect and Disease Control, a systemic drench. I'm not sure if this is still being manufactured, but seems readily available online and Bayer recommends some alternatives with different names. Anything used to control lace bug has to be applied early enough - not in the fall - to catch the first generation or the leaves will suffer the kind of damage shown in the picture. Your County Extension Service or state agriculture department can tell you when that is for your area.

Browning or curling leaf tips are rarely a sign of fungal infection. Usually the only thing fungal this time of year would cause spotting on the leaves, or a powdery look (powdery mildew). A good anti-fungal like Safer products should take care of anything like that. Usually the tip browning is because of stress. This can be under-watering, over-watering, too much sun, too much heat in general, or hot dry winds. Just use common sense with your plants and they should be fine. A little leaf tip damage is not going to harm them. If all the leaves dry up and fall off, that can be more serious, but even then they can recover fully - they have an extra set of leaves they can push out. However, if they use the second set of leaves and they get stressed again during this season, the plant will die. So its better not to let them get too stressed. Remember, Japanese Maples are not full sun plants normally speaking. If you have them in full sun it may just be too hot for them. Most of them do best with morning sun and afternoon shade. Even in hot, muggy climates like mine they thrive with morning sun, afternoon shade. Also be sure they are planted in good soil. They hate clay, and will quickly decline if planted in a poorly drained location. I plant all my JMs in raised beds with good top soil. I mulch well and have an inexpensive irrigation system that comes once every 4 days and gives them a good drink. In this heat they can quickly dry out, so I prefer some automation to help me keep on top of the watering chores. Good luck with your trees - I'm sure they'll do fine with a little TLC.