Never heard of squirrels damaging rhododendrons, but deer love the flower buds.

I also never heard of tabasco hurting plants, but don't know many people that put tabasco on plants either.

Here some other possibilities.

1) Yellowing of a leaf between dark green veins is called chlorosis. Many conditions can be responsible. Poor drainage, planting too deeply, heavy soil with poor aeration, insect or fungus damage in the root zone and lack of moisture all induce chlorosis. After these conditions are eliminated as possible causes, soil testing is in order. Chlorosis can be caused by malnutrition caused by alkalinity of the soil, potassium deficiency, calcium deficiency, iron deficiency or magnesium deficiency. A combination of acidification with sulfur and iron supplements such as chelated iron or iron sulfate will usually treat this problem. Chlorosis can also be caused by nitrogen toxicity (usually caused by nitrate fertilizers) or other conditions that damage the roots such as root rot, severe cutting of the roots, root weevils or root death caused by extreme amounts of fertilizer.

2) 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.

3) Yellow mottling on the upper surface of leaves and black sooty mold and transparent insects on the bottom are symptoms of whitefly also. They are more prevalent on certain varieties and on plants grown in protected areas. When damage first appears, it may be controlled by any of a number of contact insecticides. Care must be taken to spray the lower surfaces of the leaves where the whitefly live.

4) 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.

5) 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.

6) Light green or yellowish patches on leaves sometimes accompanies by brown spots on the back side of leaves is a sign of rhododendron powdery mildew (Microsphaera azaleae). One of the puzzling aspects of this fungal problem is the fact that two different affected rhododendrons vary in appearance. Rhododendron cultivar 'Unique,' for instance, shows almost no upper leaf changes, other than occasional very faint lighter yellowish areas, while the underside of the leaves will be completely covered in brown spots. A deep green leaf may begin to show lighter green patches, and these areas will gradually become more yellow. Another cultivar, 'Virginia Richards,' gets brownish purple spots on both tops and bottoms of leaves. This common disease is named rhododendron powdery mildew despite how little the symptoms resemble the familiar fungal disease often seen on roses and azaleas. Usually the disease doesn't produce the familiar white powder-like spores, although late in the summer some may become visible. The disease manifests instead as color changes in the leaves, followed by defoliation toward the end of the growing season. Many rhododendrons, if basically healthy, will coexist with the disease and seem to outgrow or at least survive the symptoms. Last year's leaves, once they have been hit by the disease, will always have it, with symptoms persisting from year to year until the leaves drop off. High relative humidity at night and low relative humidity during day with 70-80 F (22-27 C) temperatures is ideal for the disease to flourish.

Hope this helps.

Brodie, while it's not a problem here, I do know that squirrels eat rhododendron and azalea buds...Henry Mitchell, garden writer for the Washington Post for many, many years wrote a great article on the frustration of buds and squirrels. Unfortunately he didn't have a solution, just a deep empathy for gardeners sharing his problem.

I don't know how to answer your question as to the tabasco injuring foliage, I've never put tabasco on my own. Has you thought about putting a bit in an inconspicous place on the other rhododendron that's undamaged for comparison?
I did look up 'recipes' containing tabasco as repellent for shrubs, and found most of them listed tabasco as an ingredient, but diluted.

It's probably not Tobasco...
I use Cayenne pepper for the same reason- my squirrels love the azalea, rhodo, and lilac buds. I apply a thin Vaseline layer on the buds and then sprinkle them with cayenne. I do it on the lower buds only, so I don't put on an awful lot. I have done it on and off for a few years now, and have not had any yellowing of the leaves. Believe it or not, the squirrels have learned, and they don't touch the buds. I do it from time to time- just in case they have forgotten:) but I haven't had any problems. One of my azalea's leaves had yellowish areas at some point, but this was due to the soil not being acidic enough. I added peat moss and it solved the problem.

Ooops! I just thought to look at my bottle of Tabasco - the label reads Capsicum frutescens var. tabasco, vinegar, and salt.

Are all brands of tabasco approximately the same contents? Vinegar acts as an herbicide and could definitely damage foliage, not to mention the salt...

Hmm.. I didn't realize it contained vinegar and salt. It doesn't seem to be a good choice then.
Brodie- besides using cayenne pepper, you can also sprinkle bloodmeal on your beds (not too close to the rhodos though, it contains too much nitrogen). Squirrels hate it. Re-apply after each rainfall. This is how I am able to keep my tulips intact, by the way.

A squirrel recently devoured every one of the buds on my only Rhododendron, one that hasn't ever bloomed for me (Now I know why!) -It was loaded too and would have been so beautiful. Not wanting to experience yet another spring without a Rhodo-bloom, I purchased another plant that is loaded with buds...and promise. The nursey guy advised applying a pepper spray (which they had on their shelves) to each bud and that it's odor and taste should turn the bushy-tailed buds off from my Rhodo's many buds -Here's hopin'!

I think I'll douse my heuchera as well; another squirrel fave, it seems, at least in my garden.

>>I think I'll douse my heuchera as well; another squirrel fave, it seems, at least in my garden.

Really? They have never, never shown any preference for that plant in my garden. But, we never managed to taste the peaches off our peach tree. In the end, we just got rid of the tree. I somehow didn't feel like eating peaches with Vaseline and pepper spray :)

I just talked to a fellow that used vinegar to treat mold on bed of azalea seedlings and the fumes from the vinegar browned all the leaves. So I would avoid vinegar or any other source of Acetic acid. Salt isn't very good to put on rhododendrons either. So I would say that tabasco is a poor choice. Perhaps some other source of capsaicin would be better. Capsaicin powder can be purchased as Squirrel-Away from garden centers or as a powdered seasoning from spice shops.

Thanks for the information. I have azaleas planted under and near my oak tree which have not been attacked by the squirrels at all. Of course, there are tons of acorns that might make the squirrels content, or maybe it is because of the fact that I only see one or two squirrels in the yard at a time.

Anyway, if the squirrels do start eating the buds, at least now I will know how to handle the problem as soon as I notice it has begun to occur.

Thanks again.

I haven't had any problems with the squirrels in my rhododendron because my black walnuts produced a bumper crop last year. I've used cayenne and habanero pepper powder on and around all my plants though for the past couple of years. It takes the squirrels a couple of times getting a mouthful of it to learn but boy do they!lol I had never seen a squirrel eat so much grass! I usually buy the biggest bulk container I can find of cayenne and reapply it after a heavy or fairly steady rain. I have some cats in the neighborhood who are a little on the slow side. The ground cayenne and habanero repels to some extent the mulch digging cats too. This year I'm going to grow my own peppers so I can dry them for reserve for the squirrel and cat battle next year. Hmmmm....which reminds me, I need a new spice grinder.

I've been debating whether to address this topic, because a differing opinion to others usually doesn't go over too well. I think everyone is entitled to their opinions, though - so I do respect what everyone is saying here - and you are, of course, free to do whatever you want.

Let me say first, I've had my share of bulbs dug up by squirrels, and chipmunks - we've got a chipmunk under our stone wall that is pushing out the dirt, and causing it to look really bad, and we hope our stone wall doesn't collapse someday. I've have my share of holes in the garden dug by both of these critters. And, plants have been eaten, too.

Here is a quote from a website I found (squirrels.org) "The use of "Squirrel Away" or "Hot Pepper Spray" are also ineffective as deterrents. They can actually do harm to both squirrels, and other animals, especially when these products get into their eyes. Then how do you deal with a blind squirrel?"

I don't have a humane answer to how to keep the squirrels from eating rhododendron buds; except to cover up the whole plant with a cage (yeah, right). I know how terrible it feels to have your plants damaged. But, I just can't take the chance of harming an animal.

I'm sure I'll be very popular now - lol.

You can cover your bushes with bird netting -- doesn't take long, and it deters the nibblers. Squirrels love rhodo buds; I think they think they are artichokes (debated putting out little pots of butter!).

Seriously though, the green 1/4 inch bird netting works. You have to keep it on right through 'til the buds are starting to burst forth. Make sure you secure the netting so that it doesn't blow off the buds during spring winds. We put the netting on whilst there was still snow on the ground -- some time in January (Southern Ontario, Canada). The squirrels like the buds even more when they look so fat and green during the winter months.

One thing to watch for with the netting, is the buds push through the netting as they swell, and so can be girdled. So a couple of forays with fine point scissors to snip the netting prior to removal is advised. Also, get the smaller netting (1/4 inch?), rather than the larger -- the buds poke entirely through the larger netting; the squirrels then use it as grappling nets to get to the buds.

Detracting squirrels with various other food doesn't seem to work -- and I've found that tabasco is expensive for any large number of bushes, and as noted, it may be more harmful to plants/critters, than the largely unobtrusive netting.
I empathise with all who have lost a well anticipated crop of buds to nibblers, and the netting really helps.

Tabasco sauce & cayenne pepper are harmful to squirrels eyes. If they get these ingredients on their paws they may go so far as to scratch out their eyes. Garden Centres carry other products containing Bitrex which are not harmful and which work.

I used bird seed treated with squirrel-away (capsaicin powder) and the squirrels were not bothered in the least. They would come back for more. They didn't eat as much but were in no way harmed. However hawks, eagles, cats, etc. do like squirrel meat.

If squirrels eat Bitrex or other Denatonium containing products, they might bite their tongue off following your logic.

I don't use squirrel away anymore because it is harmful to feed birds birdseed. I makes them loose that natural survival instincts. It dilutes the gene pool and leads to unnatural behavior.

Rhodyman,
Are you saying that Squirrel Away is harmful to the birds, or is the birdseed harmful to the birds?

I added Squirrel Away to my birdseed about a week ago, filled up my bird feeder, and about four days later, it was all nearly gone...the squirrels weren't deterred in any way at all. The birds didn't seem affected; on four different occasions during the past two days, I have even had to rescue one bird who wants the seed so badly even though it is down to the last 1/4 in. inside the feeder, that he crawls under the opening in which the seed comes out and gets caught inside the feeder.

If Squirrel Away is harmful to the birds, then I'm just going to throw out what I have remaining in my container and start all over.

Thanks!
Beverly

Bird can't detect Squirrel Away. It is not the least bit harmful to birds. That is why it is sold at bird feed stores to keep squirrels out of the bird seed.

Feeding bird seed is harmful. It is not natural. It is done to amuse the home owner, not to help the birds. Birds fed bird seed loose their ability to find their own food. They be come dependent on the seed. They frequently eat seeds that don't provide the proper nutrients. It keeps them in climates where they don't belong. They fail to do natural things like migrate.

Feeding birds should only be done as a rescue measure when weather is so bad that their natural food is not available. It should never be done at the change of seasons when they need to adapt to new conditions.

They have survived 1000's of years. Lets not kill them with love.

Here is a link that might be useful: Bird Friendly Spaces

Thanks, Rhodyman, for clarifying that and for the information!

Beverly