A very sick Rhody??

Vancouver, WA(Zone 8a)

I think I have probably done something very wrong with my Rhody. This is the beginning of its 3rd year, and it has never been the best looking thing. I see all of the bulb shaped buds waiting to open and mine has 1 dead looking one and other strange looking things. I am posting a pic. Can anyone tell me if this is worth keeping in the ground? I also am having trouble with my azalea, I kind of equate the two plants as along the same lines and maybe I should stay away from those lines. Any help would be appreciated.
Thank you,

Thumbnail by vickijackson55
Hurst, TX(Zone 7b)

Hello, Vicki. This is an almost exact copy of my reply to the post you left on the Hydrangeas Forum where you asked for help with hydrangeas/azaleas. Rhododendron and azalea care is very similar since azaleas are part of the genus Rhododendron so I refer to both below as rhododendrons. Their care is similar to the one for Hydrangeas. Below I compare the care of both and end with possible causes of drooping leaves.

Rhododendrons/azaleas and hydrangeas require somewhat similar things. They both like moist soil, not wet, for example. In the South, both have to have part shade but they can grow in full sun on the Northeast. Some can also grow well in shaded areas. However, more sun stimulates more flowering so try to choose a place that gets at least a couple of hours of sun. Unfortunately, more sun may also trigger lace bug infestations in rhododendrons so do not go overboard with this in the northern half of the country.

Both do not require fertilizers in large amounts like roses do. Established rhodies require no fertilizer at all; they feed off the decomposing mulch. If your soil is deficient in minerals, apply a 6-10-4 fertilizer like Holly-tone to the soil after blooming but before July. Hydrangeas require a fertilizer application once a year in the northern half of the country (June) and twice in the lower half of the country (May and July). Nothing complicated mind you. Say 1/2 cup to 1 cup of manure or cottonseed meal. One important fertilizer difference: rhodies should not be fed aluminum phosphate (a/s) as it can be fatal to rhodies/azaleas when used in large quantities. A/S does not cause problems for hydrangeas; this amendment is used by some to make colored hydrangea blooms turn from pink to purple or blue. Weak fertilizers like coffee grounds, liquid seaweed and/or liquid fish can also be used during the growing season; but stop these before July as well. You do not want the plants to develop tender new growth that sudden winter temperatures can kill.

Both types of plants require acidic soil and will tolerate some alkalinity but not that much. Best acidic soil for rhodies is around the range of 4.5 to 6 in the pH Scale. Some hydrangeas will not react much to alkaline soils until they hit values well above neutral (7). Interestingly, most colored blooms in hydrangeas will change color when the soil pH changes but rhodies' blooms do not. Rhodie blooms last about 2 weeks (approx) while hydrangea blooms stay on thru Fall or even repeat on some varieties.

Most varieties of both plants will develop flower buds at the end of Summer or in the Fall. The buds will remain through winter and open at the appropriate time in Spring. Until they do, you just have to wait. Some rhododendron buds will bloom as late as summer. Some hydrangeas buds start opening around May and others, like the late blooming H. paniculata Tardiva, during summer (June-July or early Fall).

Both plants also require well-draining soil but here is where hydrangeas (Oakleafs excluded) will outperform a little. Rhodies develop root rot if left in standing water for long periods of time or if planted in clay soil while hydrangeas (Oakleafs excluded) can tolerate clayish soil some more. This is due to the types of roots. Rhodies have very tiny fibrous roots that only grow in the top 4" of the soil (mostly) while hydrangeas develop bigger and more extensive root systems. But do not misunderstand me, hydrangeas are not impervious to root rot.

Use the finger method if you are uncertain as to when to water. Insert a finger into the soil to a depth of 4" and see how it feels. If it feels dry or almost dry then water 1 gallon of water and record this in a wall calendar. If it feels moist, do nothing. If it feels wet, determine if any action is needed to correct this. After using the finger method for 2 weeks or so, observe how many days apart you watered. Set the sprinkler or drip irrigation to water 1 gallon of water on the same frequency. If the temperatures change 10-15 degrees up or down, re-check using the finger method again. Note: if the plant is in sandy soil, you will need about 50% more water than otherwise.

Rhodies may need a little bit more pruning once they are done flowering because the stems sometimes tend to cross. With large-leaf rhododendrons (elepidotes), you should prune above growth joints because that is where dormant growth buds are located. With small leaf rhododendrons and azaleas, you can prune just about anywhere on the stem because they have adventitious dormant growth buds everywhere. Hydrangea pruning can be a little more complicated. The 'when to prune' requires knowing the hydrangea variety and/or whether it blooms on old or new wood. But if planted in a place where it can reach mature size, you should not have to ever prune a hydrangea. The only times I have had to do that was for the sake of safety or because one side grew more than another. While hydrangea stems all grow from a crown, you have to deadhead dried-out hydrangea flowers that are still clinging to stems or prune some hydrangea stems that do not leaf out because of harsh winters.

Both plants should enjoy lots of mulch, about 3-4" inches up to the drip line. With hydrangeas, you can use either regular or acidic mulch but with rhodies, I recommend acidic mulch only.

Rolling and drooping of leaves is very common amongst rhododendrons that suffer from:
* lack of water, too much heat or extreme cold. That is how your plant prevents loosing yet more moisture. By doing this, less of the leaf surface is in contact with the sun and thus, less moisture is lost. To correct this, take appropriate action. Provide adequate moisture or just wait until temperatures return to normal.
* damage from applications of insecticides (done to nearby plants)
* root rot caused by overwatering or planting in a location where water tends to collect (too much soil moisture)


This message was edited Mar 15, 2009 5:38 AM

Wilmington, NC(Zone 8a)

Hey, there! I'm so proud of this little guy for hanging in there! I hope by now you have resolved the issue. But just in case you couldn't figure out what was wrong, I figured I could help. I can't be sure but it looks like it is in a location that gives it too much sun. In nature they are woodland creatures (usually under pines) and like to get morning sun only. Or dappled sun throughout the day. They also have shallow root systems and they do not like haveing "wet feet" so plant in well drained soil with plenty of organic material like peat soil. Again, that's how they grow in nature. Most importantly you will have more success if you plant shallow, meaning 25% of the root ball above the soil line and then mound soil up to the plant. When you're done it should look like it's growing on a little hill. I am a Master Gardener volunteer in Wilmington North Carolina, which is the home of the Annual Azalea Festival. I hope these tips are of some value to you.

Thumbnail by mccaine
Hurst, TX(Zone 7b)

Good suggestions, mccaine. By the way, I love going thru azalea festivals in Spring (although mine is in Tyler, Texas) and seeing the blooming shrubs. Please post pictures of yours if you attend and if it is not a bother.

Caldwell, NJ(Zone 6a)

It looks like many of my healthy small Rhododendrons in the March garden. Wait for another month and see if it hash't recovered. or for now look carefully at the terminal stems and see if they are puckered. If they are you do have a problem , if not wit the month

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