organic fertilizer for rhododendrons and azaleas?

How do I feed rhododendrons and azaleas organically? In particular, I have several large rhododendrons looking chlorotic. Could they be yellowing because of some other problem? Our soil is acidic already, so I think mostly they need nitrogen. I don't have enough compost to side dress them all! Is there an organic product I can buy for this purpose? Any suggestions?

Hollytone, I think, is the name. It's by Espoma...

seaweed emulsion maybe?

I didn't realize Hollytone was organic.

Here's an interesting article on feeding Rhodies:

http://www.rhodoniagara.org/feed.htm

It does not go into the type of fertilizer, it just specifies a low nitrogen/high phosphorus feed before the major phase of leaf growth. In an organic program, you can use a fish emulsion with a higher middle number (like a 2-3-0) or you can use soft rock phosphate. Soft (colloidal) rock phosphate, like all forms of P, does not "travel" well in the soil. It needs to be worked into the soil to root level. Rock Phoshate is very slow to release it nutrients (faster in the acidic soil you've got) so one application will last for an entire season, perhaps two.

Bone meal is high P and somewhat faster acting, but if you're an organic purist or you want to adhere to strict organic standards, bone meal is not acceptable.

Kelp or seaweed, whether liquid or dried, does not generally supply P or N. Use kelp for overall plant "robustness", stress resistance, and strong thick stems. Kelp supplies K and many trace elements/minerals.

If you can find some low-N/high-P fish emulsion that you can use as a soil drench, that would work quite nicely.

I happen to have on hand a gallon jug of "Alaska Fish Fertilizer" 5-1-1, would this suit my purpose?

I suppose the info on the jug will specify how much to dilute it.

Okay to apply now, or should I wait until after flowering?

I checked out two websites about the time for fertilizing and they seem to contradict one another. The niagra one says they should be fertilized when the roots are growing, before they form new shoots (I believe that would be NOW for me). But the Missouri website says fertilize in May.

Also, I'm not sure the fertilizing will solve my yellow leaves problem. Could be some other cause.

Maybe chelated iron in a foliar spray?

I hope this is helpful: lots of photos:

http://www.flounder.ca/FraserSouth/basics/non-disease-problems.asp

and this thread:
http://forums.gardenweb.com/forums/load/azalea/msg1113110219815.html



This message was edited Mar 18, 2006 7:11 PM

I haven't checked your links yet, but I wonder...is it likely that the soil is iron deficient if our well water is chock full of that element? I guess I should have a soil analysis done, instead of sitting around wondering.

I don't know what kind of yellowing you have, and I'm not an expert on this (the photos show different kinds). The problem could be in the plant's ability to take up iron, not in the available iron. But you said the pH was low, so I don't know why that would be.

Your 5-1-1 does not count as low N. You'll want something with a middle number that is higher than the first number.

Re: yellowing. Leaf yellowing is caused by so many different problems that it's impossible to give advice without knowing many many details about your feeding regimen, your soil type/analysis, the plants' situation, and the plant diseases common to your area/neigbhourhood. If you have a photo, you could post it on the rhododendron forum.

Thanks zeppy and bev. I have been busy and not had the chance to look at the links above. They will probably be helpful. I will also get over to the rhododendron forum with a photo as soon as my schedule opens up. Again, thanks!

Mine did nothing until I used ammonium sulfate. Organic sulfur didn't seem to help. I realize it's not organic but being the only no-no I use, I rationalize a little is OK. Hopefully the area will get to where it doesn't need it, but I struggled with NO GROWTH for several years--how did they stay alive? For now, I use the stuff.

"Bone meal is high P and somewhat faster acting, but if you're an organic purist or you want to adhere to strict organic standards, bone meal is not acceptable."

Why is bone meal not acceptable by strict organic standards, but fish emulsion is okay????

Just trying to learn about organic growing.

Fish emulsion just crushed up fish goop? You could make it yourself if you are really a purist....and want all the cats within 5 square miles staring at you......
Debbie
:)

I read dried, used tea bags are good for acid loving plants like blueberries, rhododendrons, and azaleas. I am trying them around our blueberries and will let you know if it works.

Interesting question about the fish emulsion v's bone meal. I haven't looked into it, but could it be that bones are not from organically fed animals, whereas fish come from the sea and are by nature organic? Other than that I can only think it is in the manufacturing process.

Adding my note on rhododendrons and feeding. I know you said you have not got enough compost, but if you can manage to make more, in particular with leaves, that is possibly the best method of ensuring healthy rhodos.

When I first moved to the present property there was a few rhodos along a border, on the north side of a south facing hedge. In general, they were quite poor. I set about to give them a boost, first by pruning out any weak non-flowered stems. I then gave them and the surrounding bed a thick mulch of compost, made from horse chestnut leaves and grass cuttings etc.

Once the bed was mulched there has been few weeds, and so the roots have not been disturbed. The mulch has been on about 5 years, and it has broken down and provided the plants with all they need. From being poor looking plants which had few flowers, they have grown robustly each year and all have flowered prolifically, they look very healthy. I also have some azaleas that were not mulched for a start, but once mulched their performance and health has improved dramatically.

In nature these plants grow around the edges of trees in leaf litter, and it would seem they get all they need from that. I have acidic, sandy soil so I suppose it is perfect for them, but it is the addition of compost that made the difference. I think leaves also have a slightly neutralising effect, I have read that mulching should not be done too often with leaves as it will cause the soil to become too alkaline.

What does your County Extension Agent say?

I need some advice on a organic spray or cure for slugs in my garden. I have tuna cans buried to rim with a yeast water mixture in them and these catch all kinds of crawling critters, but slugs are attacking my tomatillos and I need a spray. I do not want to use salt. Any suggestions would be appreciated. Thanks Txsdar

Best way is to go out at night when they are munching, pick them up (I use a trowel) and take them somewhere else. If you do it on a regular basis you will soon get rid of them. Look in places they are likely to hide, under pots etc, I have done this for a few years and get very few slugs now.

No spray is good for other wildlife.