unhealthy rhodys

Robes22April 3, 2013

Last fall I planted 11 Cunningham White rhododendrons. My method of doing this was as follows: dug a hole a little bigger than the pot they came in, put the compacted root ball in the hold, heavily compacted the soil around the root ball.

Now its spring and the rhodys look like they are having some severe environmental stress, brown spots on leaves, some yellowing leaves and some leaves curling under.

My questions are am i right in saying its environmental? from the pics i compared mine to online it seems that way. Also, should I dig them up, scratch up the root ball and loosly plant it back in the hole? i think i may have compacted it with my foot too much. Let me know your thoughts please. I am new to landscaping/gardening so I am not sure if I planted them the right way. Thanks.

Thank you for reporting this comment. Undo
akamainegrower

Rhododendrons need a highly organic, loose planting medium that will provide a lot of air space, excellent drainage, and good moisture holding ability. Placing them in a just-big-enough hole and heavily compacting the soil around them is pretty much the opposite of what they need.

'Cunningham's White is an especially tough and adaptable variety, so digging them up and replanting may save them. This will only help, however, if the native soil is already suitable or you amend it enough to make it so. Container grown rhododendrons are almost always in a peat-based medium. Roots will not easily extend out into a soil that is totally different, especially if it is clay based. The existing root ball dries out, shrinks and becomes very difficult to re-wet. This has very likely already happened to yours. Dig them up, amend the soil or create a raised bed, distress the root ball, soak in water to re-wet, if necessary ,and then replant.

    Bookmark   April 4, 2013 at 5:45AM
Thank you for reporting this comment. Undo
akamainegrower

Rhododendrons need a highly organic, loose planting medium that will provide a lot of air space, excellent drainage, and good moisture holding ability. Placing them in a just-big-enough hole and heavily compacting the soil around them is pretty much the opposite of what they need.

'Cunningham's White is an especially tough and adaptable variety, so digging them up and replanting may save them. This will only help, however, if the native soil is already suitable or you amend it enough to make it so. Container grown rhododendrons are almost always in a peat-based medium. Roots will not easily extend out into a soil that is totally different, especially if it is clay based. The existing root ball dries out, shrinks and becomes very difficult to re-wet. This has very likely already happened to yours. Dig them up, amend the soil or create a raised bed, distress the root ball, soak in wter to re-wet if necessary and then replant.

    Bookmark   April 4, 2013 at 5:46AM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

What asamainegrower said was worth saying twice.

To get an idea of how you should open up the roots of potted rhododendrons look at the link below on how to plant rhododendrons. I suspect you have a very dry rootballs and need to dig them up and soak the root balls in water for an hour or two and then plant them correctly.

Just an addition, besides peat based media, evergreen bark dust and fine evergreen bark particles are also often used, especially on the west coast.

Here is a link that might be useful: How to plant potted rhododendrons.

    Bookmark   April 4, 2013 at 8:44AM
Thank you for reporting this comment. Undo
Robes22

Thanks for the info...they don't look terrible, they just don't look perfect. Ill try and post some pics tonight when I get home. Couple of followup questions. They were planted in an old forest area where trees had grown for many years. Some of those trees became safety hazards so j had to cut them down. Given that a lot of the trees (not all) were pine how organic do you think the soil is? I am too new to planting to be able to tell. Should it be amended? And if so what is the name of the product and best way to use it?

What is the best way to break up the rootball and how much of the rootball needs to be broken up?

    Bookmark   April 4, 2013 at 9:22AM
Thank you for reporting this comment. Undo
Robes22

Here is a pic of probably the worst looking one

    Bookmark   April 4, 2013 at 6:58PM
Thank you for reporting this comment. Undo
Robes22

And one more pic of them...what's your diagnosis guys? Thanks for all your help

    Bookmark   April 4, 2013 at 6:59PM
Thank you for reporting this comment. Undo
akamainegrower

The pictures show winter burn - browning and curling from the combined effects of winter sun, cold and wind. The spotting is likely from any one of a number of leaf spot fungal diseases. The leaves - at least in the photos - are an unhealthy yellowish color. 'Cunningham's White' should have deep green leaves when it's receiving adequate nutrition.

It may be that the soil has good organic content from years of accumulating pine needles and leaves. Usually it's pretty obvious - loose, easily dug, contains recognizable bits of pine needles, leaf parts, cones, etc. Not all wooded areas are like this, though. A soil test will give organic content, as well as valuable information about pH, NKP content. It would be well worth having done.

Everyone has a favorite amendment depending on what works well and is locally available. Mine is Nutrimulch, a mixture of compost and bark. Partially decomposed softwood bark is also excellent. Peat as available in bales tends to do more harm than good.

One of the best ways to prepare the root ball for planting is to use a hose with a forceful stream of water to wash away most of the planting mix. A hand garden cultivator with sharp tines also works well.

Apologies for duplicate posts above.

    Bookmark   April 5, 2013 at 5:23AM
Thank you for reporting this comment. Undo
Robes22

So after seeming the pics do you still suggest I re-dig the holes bigger loosen up the ball with hose etc and then reolant them in loose soil?

    Bookmark   April 5, 2013 at 7:52AM
Thank you for reporting this comment. Undo
Robes22

And how would you treat the fungus

    Bookmark   April 5, 2013 at 8:06AM
Thank you for reporting this comment. Undo
akamainegrower

The leaf spotting, as noted elsewhere, is not a major problem. The overall health of the plants most definitely is. Unless their root balls are loosened, wetted and replanted into a more suitable soil, the plants will eventually die.

In planting rhododendrons of all kinds, it's really a mistake to think in terms of "digging a hole" as you would for many types of trees and shrubs. The ideal soil for rhododendrons is loose and airy enough so that you can scoop out a shallow depression with your hands, or, at most, a hand cultivator. Water in well, compact the soil with gentle hand pressure only, then mulch.

    Bookmark   April 6, 2013 at 5:20AM
Thank you for reporting this comment. Undo
Robes22

Thanks. I'm gonna get some compost to add to the soil and soil acidifier today and replant them properly

    Bookmark   April 6, 2013 at 9:19AM
Thank you for reporting this comment. Undo
Robes22

Double post sorry

This post was edited by Robes22 on Sat, Apr 6, 13 at 9:22

    Bookmark   April 6, 2013 at 9:20AM
Thank you for reporting this comment. Undo
Robes22

Ok so i spent six hours today working on my rhodys. I dug them up, loosened the rootballs and sooked them in buckets of water for about twenty minutes each before replanting. I checked the drainage of my soil and it has very good drainage. I replanted them in a much wider hole with loose soil and a compost peat mix (opposed to plain soil the first time) as well as some sulfur acidifier. So in theory they should be exponentially happier now. I am planning on mulching them next weekend.

I would like to address the leaf yellowing, what is the best way to do this? I have read about people using dry blood but wanted to hear evryones suggestion. Thank you all so much

    Bookmark   April 7, 2013 at 1:01AM
Thank you for reporting this comment. Undo
Robes22

Thanks. I'm gonna get some compost to add to the soil and soil acidifier today and replant them properly

    Bookmark   April 7, 2013 at 5:29PM
Thank you for reporting this comment. Undo
rhodyman(SE PA, USDA Z6)

Never use aluminum sulfate as a soil acidifier. It will eventually kill rhododendrons. Powdered sulfur is the best. It is slow acting but very long acting.

The best fertilizer is Holly-Tone. It has an organic nitrogen which is important to rhododendrons and other plants that need mycorrhiza to help the roots function. Chemical nitrogens can kill off the natural mycorrhiza in your soil. But only fertilize once per year at most and only at half the rate recommended on the package. Be sure to mulch the soil to keep it cool and conserve moisture.

Good Luck!

Here is a link that might be useful: How to grow rhododendrons and azaleas

    Bookmark   April 8, 2013 at 10:53AM
Thank you for reporting this comment. Undo
Robes22

Ya I've read that holly tone is the best. When should I use it? The fall the summer etc?

    Bookmark   April 8, 2013 at 4:53PM
Thank you for reporting this comment. Undo
morz8(Washington Coast Z8b)

Robes, it might be worth your time to read through the site Rhodyman has linked for you. It's his by the way, and some time and effort has gone into it...

It will answer most of your questions including those of fertilizing. Fertilizing isn't necessary in every garden, it depends on the soil type but - "Fertilizing plants should be done in May, but not after July 1. Late summer fertilization may force out tender fall growth that will be killed by the winter"

And please stay with the hollytone. Blood meal is high nitrogen and not appropriate for shrubs like rhododendron.

    Bookmark   April 8, 2013 at 5:00PM
Thank you for reporting this comment. Undo
Robes22

Will do. Thanks

    Bookmark   April 10, 2013 at 1:14PM
Thank you for reporting this comment. Undo
Robes22

how long do i need to wait before I will see if the changes i made worked? or if I need to do something else to them? I really dont want them to die. It's been almost a week and they look the same if not worse. Should I be watering them now?

This post was edited by Robes22 on Wed, Apr 10, 13 at 22:00

    Bookmark   April 10, 2013 at 9:44PM
Thank you for reporting this comment. Undo
morz8(Washington Coast Z8b)

Have we established where you are? You gardening zone isn't showing with your sign in and I'm not sure what kind of weather you are experiencing. If its been bright, warm, dry or windy and you haven't had regular Spring rain, you will probably want to treat them as you would any newly planted shrubs and pay extra attention to water. Moist while not soggy. Looking worse wouldn't be good. But they may not look better until they begin to establish and this years foliage buds open. If conditions have improved for them, that new foliage should look healthier than the old.

    Bookmark   April 11, 2013 at 12:12AM
Thank you for reporting this comment. Undo
Robes22

I'm zone 5 not sure why its not showing. so I won't know until they bloom and put out there new growth for this year?

This post was edited by Robes22 on Thu, Apr 11, 13 at 9:10

    Bookmark   April 11, 2013 at 6:21AM
Sign Up to comment
More Discussions
Anybody out there have luck with Rhodos in Southern Arkansas?
Looking for any feedback from Houzz readers who have...
Rusty Empire
Do any Encore Azaleas attract hummers?
I may be having some azaleas replaced with dwarf, due...
Bama_Joe
rescuing older, non-blooming azaleas
When we moved into our (very overgrown) house last...
pollyfan
thoughts on permanent soil enhancement
This is more or less a followup to Mainegrower's questioning...
davidrt28 (zone 7)
© 2015 Houzz Inc. Houzz® The new way to design your home™