Hello, beej_2007. Many rhododendrons along the northeast corridor and around the Great Lakes have suffered from winter injury by the late cold spells. You could be experiencing winter injury & scale (an insect whose excrement turns the stems black). In small numbers, it can be ignored but otherwise, I would release beneficial insects like ladybugs or spray with a horticultural oil like Safer. {{gwi:390045}} shows shows what the insects look like; {{gwi:390047}} shows the damage caused by scale. {{gwi:390049}} is a close up of the insect.

There are several individuals who have posted pictures of winter injury in other posts. Can you take some pictures so we can see what you are observing?

Luis

This past winter appears to have forced a redefintion of what "Ironclad" means. The problem is that it was warm until mid January, then suddenly became cold. As a result, several species and hybrids had sap flowing until the cold spell and never truly hardened off. I have seen massive damage to "roseum elegans", long considered the best of the ironclads. At the same time, my Camellia, Blood of China, grown in hte same garden, did not brown a leaf, or lose a flower bud. Seems to me that this year the issue was an inability of some plants to regulate their hardening off ability.
You can do the scratch test to see of there is green under the surface. You can wait until the healthy parts start to grow, then remove the dead material.

my rhody leaves and buds are all brown. we had a warm spell then a deep freeze did damage to one of my rhodies. i have green in the bark but should i remove the brown withered leaves? thanks

You can remove the leaves and buds, happee2bme. Or you could let the plant drop the leaves later on. If it has not dropped the browned leaves by month end, I would take care of that.

Note.... I would be more concerned with giving the plant some TLC until it recovers and leafs out. Maintain the soil moist and skip fertilizing until after the plant has recovered. A little liquid seaweed is ok.

Luis

oh thank you..i will look for the liquid seaweed...never heard of that..

where do you get it?

It is a very simple fertilizer, a foliar feed with a low NPK ratio, particularly useful when a plant is stressed and fertilizing with chemicals is not recommended. Usually sold in plastic containers.

Click on the link below to see a picture of a common one. Since it is for temporary use, you can use either the regular version or the acidic version for acid loving plants. Once your plants recover, use the rest on your other garden plants.

Luis

Here is a link that might be useful: Liquid Seaweed

thank you

I'm having the same problem with my rhodies this year. Last year they were beautiful - they are very mature (approx. 40 yrs old) and this year lots of dead wood and very poor buds and leaves. Was the warm weather then cold in NJ to blame? What can I do to save them?

For many of us, this past winter our plants took a beating with the very unusual winters some of us had with warm weather followed by late freezes. They have what is more typical of drought damage but in this case was caused by the warm weather followed by late freezes. It causes Botryosphaeria dothidea which causes leaves to turn dull green and then brown and roll and droop. Cankers form on branches which may girdle the branch.

This is the most common disease of rhododendrons in the landscape. A typical symptom of this fungal disease is scattered dying branches on an otherwise healthy plant. Leaves on infected stems turn brown, then droop and roll inward. These leaves often lay flat against the stem and will remain attached. The pathogen can infect all ages of stem tissue through wounds, pruning cuts, and leaf scars. Heat, drought stress, and winter injury can increase disease incidence. Cankers on branches can gradually grow through the wood until the stem becomes girdled. Diseased wood is reddish brown in appearance. Discolored wood viewed in longitudinal cross section often forms a wedge that points toward the center of the stem, and the pith may be darker brown than the surrounding wood.

Sanitation and applying a fungicide such as metalaxyl (Subdue) after pruning my provide some control. Plants should be grown in partial shade, with mulch and kept well watered during dry periods. All dying branches should be promptly pruned out in dry weather and all discolored wood should be removed. Plants should also be protected from rough treatment during maintenance activities to prevent unnecessary wounds.

Here is a link that might be useful: Rhododendron and Azalea Troubleshooting