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I am hoping for some advice on this. Last spring I bought 4 Rhododendron bushes for my yard in Gearhart. They looked great for a few weeks and then the bright green leaves turned yellow and droopy.. and have stayed that way for a year.. The soil is very sandy so we did add a fair bit of top soil to the hole we dug when we planted them. A friend told me to try Epson salt which we did and that did not help. We have also fertilized them quite a bit and no change. I am thinking it is soil PH.. Probably they don't like the soil ph at the coast. Has anyone had any luck fixing a similar problem on the coast? Thanks for responses in advance.
 

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They grow great just up the road from you in Astoria so it’s certainly not coastal weather or soil PH if the topsoil you used is from the coast or similar. If what you used as topsoil is something out of a bag from the local garden supply outlet, it isn’t topsoil no matter what it says on the bag. What did you use as fertilizer? Did you add Lime? Rhodys love acid, not Lime. I would try some easy to dissolve high nitrogen fertilizer like Miracle Gro to give it a quick boost. Watch leaf color to see if plants start to green up. If any of the other things I mentioned apply, fix them first.
 

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Not enough background to say exactly why the color faded. Rhododendrons have fiberous root systems that are susceptible to root rots and to over watering. I'd also say that in my experience, a very high majority of issues associated with plants is related either to over, or under watering. Without knowing more, I'd lean toward over in this case.

I'm with others who mentioned that the natural soil pH at the coast in general is on a scale that is favorable to Rhododendrons - slightly acid, and down to perhaps 5.5 would be just dandy. Easy on the fertilizer - stressed out roots can't pick up much, so I'd like the idea of the mild liquid feed, but sparingly. A possibility is sodium toxicity that can burn back roots to sodium sensitive plants like rhodies.

Another possibility is exposure. Generally Rhodies are an understory plant that can often tolerate some to a lot of exposure. This said, if the plant was used to full sun, then moved beneath a thick canopy, the leaves would fade from deep green to lighter green pretty quickly.

Spring is here, so if mother nature was keeping the surrounding soils too damp, there may be some relief there. I've grown a few Rhodies in commercial nurseries. #1 - make sure that you aren't over watering. And, by the way, when you do water, water very thoroughly, but then let the soil dry for some time before you hit them hard again.
 

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Dogz is spot on about them being acid loving. If you notice at nursery shops they sell specialized fertilizer that is ph suitable just for Rhodies
 

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This site say's stay away from fertilizers with "ALUMINIUM SULFATE." Blueberry fertilizer has this ingredient. Local Ace hardware has one that's 60% Nitrogen/30% Sulfur. Blueberries take a little sulfur stuff once every 3 or 4 years to maintain acidity. The sulfur/nitrogen has a picture of a Hydrangea on it from Ace Hardware.
 

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My wife is a pour over coffee junky. I keep the grounds and put a half a cup around each blueberry bush before they bid in the spring. I do the same with the hydrangeas that I grow with the blueberries. You can tell the acid level of your soil by the color of the hydrangeas. The darker and more brilliant the blue means you are in the acid zone you need.
 

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Possible sea salt in the soil?
I heard somewhere that it can be detrimental to plant growth.
They grow most excellent at the top and on the east side of the coast range.
I know that from surveying up there. Some of the old 1940's clear cuts, that were never re-planted,
have hundreds of acres of nuttin' BUT rhodies. And they are in some places 8' tall or more.
And grow so thick a mouse can't squeeze through.
Try chain sawing your way through several hundred yards of that stuff all day, To get a straight line of sight for the survey instrument. Then they are growing so high along the traverse line, that there is nowhere to throw the debris. Not fun!
I grew to hate rhodies after one summer of cutting my way through so many miles of that stuff.
 

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only use organic bag soil mixes as the others are a gamble of whats in them. rodes can grow if just stuck in the ground and walked away from. most planted things need none or very little fertilizer until they get started. and most people over fertilize.
many mulches were sprayed with 24d or worse, to kill weeds and it does exactly that and goes on killing.
 

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Yea, over fertilizing is a killer. Especially on a new plant just put in the ground which includes tomatoes in the veggie garden. Next door neighbor was complaining about her Rhody not flowering well. It was in a shaded area and leaves were very dark green. Told her to quit fertilizing it. Now it has beautiful blooms. A lot of times the best thing a person can do to plants is nothing at all. Continuous grooming, feeding, watering, tinkering can take away a lot.
 

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This site say's stay away from fertilizers with "ALUMINIUM SULFATE." Blueberry fertilizer has this ingredient. Local Ace hardware has one that's 60% Nitrogen/30% Sulfur. Blueberries take a little sulfur stuff once every 3 or 4 years to maintain acidity. The sulfur/nitrogen has a picture of a Hydrangea on it from Ace Hardware.
60% nitrogen is scary high, and is more than likely a chemical salt that can burn the roots of most plants.
I'd stay away from it or use very little.
 

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Discussion Starter #16
Possible sea salt in the soil?
I heard somewhere that it can be detrimental to plant growth.
They grow most excellent at the top and on the east side of the coast range.
I know that from surveying up there. Some of the old 1940's clear cuts, that were never re-planted,
have hundreds of acres of nuttin' BUT rhodies. And they are in some places 8' tall or more.
And grow so thick a mouse can't squeeze through.
Try chain sawing your way through several hundred yards of that stuff all day, To get a straight line of sight for the survey instrument. Then they are growing so high along the traverse line, that there is nowhere to throw the debris. Not fun!
I grew to hate rhodies after one summer of cutting my way through so many miles of that stuff.
I hear you I used to cruise timber and we had to do a traverse with survey tape of the unit first to get an accurate acreage total nightmare but now they have GPS so much easier.. I don't miss those days in the brush..
 

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I had blueberry plants that were established for at least 10 years and the crops became kind of meh. I researched on line what they might need and it was sulfur. When I read the amount of nitrogen I was skeptical and so used sparingly. Applied late winter and got enough berries with phenomenal foliage growth that summer. The next 3 years were bumper crops on new foliage. Rhodies I don't know, Blueberries can benefit from sulfur. Key Word : Sparingly
 

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Sulfur is one of the biggest elements plants need to turn NPK into useable food.
There's a long list of elements, bacteria and fungi that are need to have healthy soil not just dirt.
Plants won't grow well in dirt.

I'd start by testing the PH of the dirt/soil. If your on the coast, I'd guess you're in a ok PH range. Next I'd check your water PH. If your water PH is above 8 it COULD cause a problem with the PH in your root zone.
How much are you watering? After the first transplant they shouldn't need much water. Their roots should find enough moisture in the native dirt. Unless they have all day sun.
When you bought the plants, were they outside in the sunlight or were they under artificial light? Moving from artificial light to direct sun will cause them to do what you've described.

Hows the drainage. Is there a lot of standing water in the area in the winter?
What time of the year did you first plant? Spring summer fall?
Have they started their spring bloom? The transplant shock could have stayed with them all season, (last year) but now they've had a season to establish and grow roots. I wouldn't do anything tell they show their spring growth.

I wouldn't use any salts (fertilizes) at this point. I would buy a fish fertilizer.

Because it's not for consumption any fish fertilizer would work. Alaskan at ace would work well. I would not recommend using the alaskan on anything you intend to consume because it's high in heavy metals. Fish hydrolysate is what I'd use for veggie gardens or anything I'd consume.
The fish will feed your plants, bacteria and fungi in your soil.
Salts kill everything good in the soil and you will loose the natural way plants uptake nutrients.

Last, but not least, sometimes it's easier to remove said plants and start over...............
.02
 

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Most topsoils are going to PH around 7.0, so when you test your soil, make sure you test the soil around your root zone. I.E the topsoil sand mix.
The topsoil you added might of raised the PH out of the preferred zone.


So many variables, it can be hard to pinpoint.
 

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I enjoy scrolling through the comments on this thread. As a person who studied ornamentals (bs Hort '90) I've grown rhodies commercially (decades) and have also developed retail fertilizer blends (sold at Freddy's) - I've got my opinions. I'd also say I have a ton to learn about the cultivation of plants - just throwing my two cents out there.

The plant going off-color within a year of planting into the landscape could be related to a few factors either exclusively or in combination.

Foliage going off color can most likely be related to nitrogen levels in the leaf tissue. This can be due to a deficiency in the root environment or MORE LIKELY, is a result of roots that are compromised. Nitrogen is a mobile nutrient element or in other words, the plant can move the nitrogen from older leaves into newer leaves. If you closely inspect the plants, are either the upper or lower leaves greener? Having that information may provide some insight into what is going on.

If the yellowing is occurring between the veins, but with deeper green veins, then it could be another nutrient deficiency.

How big are the plants? Are the symptoms consistent for all of them, or more pronounced in a couple? Were they all treated the same? If you were to lift a plant and inspect the roots, do you find that there are lots of actively growing roots, or do they look tanish/brownish and dormant? This time of the year, they should be WHITE and actively growing. If you smell the roots, does it smell fresh or anaerobic? If they aren't getting enough oxygen, then they will suffocate (there can be either a slight to very strong off-odor). Poor drainage OR watering frequency can severely compromise roots.

As the consensus suggests, the native soils on the coast are naturally lower on the pH scale and considered somewhat acidic. This is ideal for Rhododendrons. Native or natural soils have a high CEC (Cation Exchange Capacity) relative to commercial growing mixes. This provides a great deal of buffer and (as earlier suggested) has a population of biology (for example mychorrizae and beneficial bacteria) that create a complex system and is part of the system that allows the plant to harvest the existing soil nutrition. Excess granular fertilizer applications can hurt the plant both by burning the roots and also kill the beneficial microbes that associate with the roots. This would require a pretty heavy dose in native soils because of the buffering capacity of soils. If you added fertilzer, it would be of value to know what kind and how much. Organic or natural fertilizers can be considered safer because they require biology to break them down and could be considered a form of slow release. Much more difficult to get a dose that is phyto toxic to plants. There are also "Slow Release" or controlled release fertilzers available. Again, tough to get a dose that would be toxic because they release (at least partly) as a function of temperature. Osmocote would be an example. However, some fertilizers are highly soluble, an extreme example would be urea with an analysis of 46-0-0. Even with the buffering capacity of soil, a dose of this could easily fry the soil and the plant roots.

Generally speaking, if a person wants to fertilize when planting, using a slow release with a nutrient ratio of 1-3-2 (NPK). Why? Some nitrogen since it is mobile in the root zone, 3x the phosphorus because phosphorus is associated with root development and why double the potassium? Well, potassium can be associated with vascular movement throughout the plant. I'd absolutely avoid micronutrients until i absolutely knew there was a natural deficiency. Sulfur, Magnesium and Calcium are often referred to not as macro or micro nutrients, but secondary nutrients. So for the suggestion of supplemental sulfur - I'd shrug my shoulders and say that in my opinion the sulfur levels are less likely to be a contributing factor than the airspace in the root environment. If you were producing plants commercially, then soil and tissue samples would be in order along with water tests. I would be very surprised if an issue was related to your irrigation water characteristics. Rain water is absolutely not an issue.

IF your soil had an excess of sodium, it is possible for this to be toxic to the plants. If you have healthy maples in the area, they are particularly sensitive to excess sodium, so we may be able to eliminate that from the list unless you added sodium to the root zone when planting.

Roots could be perfectly healthy. Nutrient could be perfectly in balance. And the plants can still be off color. Why? This could be related to the exposure the plants are in and or could be simply that the plants were acclimated to a different exposure when being grown commercially. The plant is pretty sophistocated and adaptable. It arranges the cholophyll based on the exposure of each and every leaf to the sun. If/When the plant is relocated, that arrangement of chlorophyll is no longer optimized and can have a symptom of either dropping the leaf, having the leaf become sun burned, or could result in a leaf going off-color. Depending on the variety of rhododendron, it is possible that when planting, the exposure is different and the foliage goes off color. It is also possible that as the new flush emerges, it basically takes inventory of the quality and type of light exposure it gets, and the foliage color is closer to the color of the foliage when you picked the plants off the retail shelf.

Do you happen to know which variety the plants are? There are literally thousands of rhododendron clones on the market. If you said you purchased The Honorable Jean Marie De Montegue, then you should target the deepest green foliage contrasting from the deep red flowers. If you purchased a dwarf like Ken Janek, then the leaf as it emerges has indumentum that looks very pale on the surface, then becomes a medium green as the "hairs" brush off. But with this much variety, it is possible to have a variety that can be deeper green under commercial growing conditions and will fade in a natural growing environment. This is all part of the range of characteristics of this group of (mostly) evergreen flowering ornamentals.

What if the roots are happy, the exposure is right and there is a balance in the soil nutrition? Well, then another option for off color foliage could be the small crawling creatures - mites for example. I'd have thought by the time a person noticed the foliage was pale, that they'd also recognize some stipuling of the foliage (dotted pattern) and or webbing that can be present when populations of mites are high enough. I'd put this low on the list of options both because it wasn't indicated and also because there are lots of native rhododendrons and mite populations can be present, but there are natural forces that seem to keep these guys in check.

Bottom line - I'd absolutely bet on an opportunity to improve root health by either relocating plants to an area with better drainage or as previously suggested, apply more patience with more time between good irrigation soakings.
 
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