I bought two repeat bloomer hydrangeas in early spring and have had very mixed results where they are planted. They have been growing and blooming well but I have been constantly battling leaves turning a sort of rust color starting at the edges and sometimes spots. They get full sun all day with no real shade and I am wondering if it is too much and what I am seeing is sun scald. Anyhow, the question is -- I want to move them to a spot where they will get less blazing direct sun. But since they are fairly new plants I am worried about transplant shock. Would you suggest doing it this fall or waiting until next spring? I live in Zone 5. Thanks!
Transplanting Help
Can you post some pictures? It could be too much sun, but in your zone I think you can grow them in full sun so it could be that they just need more time to get settled in. It won't hurt them to move them to an area where they get a little more shade but I'm not sure if you need to. The spots that you're seeing could also be caused by overhead watering--try to be careful not to water in the evening and when you do water try to make sure water doesn't get splashed back up from the soil onto the leaves.
Hydrangeas are pretty strong plants. It is very common to have to transplant them because of problem with your first planting location. Just make sure that you extract as much of the root system as possible. You could also wait until the plant goes dormant in early Fall or late Spring (when the soil has not frozen yet).
I will take a picture of the leaves tomorrow and post it. I try not to overhead water and never water in the evening. It has been weird weather in MI this year and a lot of my plants are battling bacterial spot and powdery mildew. Very hot followed by huge deluge of rain and then nothing for several days. Hopefully someone can figure it out after I get the picture up. Glad to know I can move it either way though.
OK. I am going to post a few pictures to show the variety of what the leaves look like. They usually start like this -- just a little yellowing and sometimes reddish around the edges.
Then sometimes the yellowing progresses and includes spots like this.
And this
This about the worst that they look before I get frustrated and clip the leaf off.
Sun scorch makes the leaves in direct contact with the sun turn yellow as you see in the pictures. But only leaves in direct contact with sunlight are affected at first; these begin to yellow out until they are all yellow. You also should notice that the tell tale sign of iron chlorosis (iron deficiency) is absent. Yellowing of leaves and leaf veins remaining green would signal a mineral deficiency. The spots are opportunistic fungal infections or normal leaf spots that generally become more obvious near the end of the growing season.
I would try to address the sun scorch problem first: either transplant now or later; if later then erect a structure to provide shade or use something to provide shade (a piece of cardboard will work; so will shade cloth). Control the fungal infections by using clean practices: do not water the leaves; water the soil early in the mornings instead; plant debris that accumulates under the shrub should be disposed of; dispose of leaves/blooms in the trash when you have fungal issues; do not plant shrubs close to each other so air currents can dry the leaves quickly, do not over water; etc.
I could not tell from the pictures what the shrub looks like. I was trying to determine if the yellowing problem occurs in leaves that have little direct contact with sunlight. Some mineral deficiencies or excess can also cause this problem (zinc, for example) but are rare. The problem would then be random throughout the shrub. There are a few kits that can test for nitrogen, potassium and phosphorus problems; a soil test & leaf sample sent for analysis is the only good way to test for all types of mineral deficiencies or excess. If this was your problem, other plants growing near might show signs of issues though.
Mites can also cause yellowing of leaves but you would also see distorted growth on the leaves –especially new ones- and you would also notice some webbing. I did not see those problems in your photos. If you want to make sure that you do not have mites, place a 8.5" by 11" sheet of white paper below the plant and shake the stems above. If you see dots or “specks of dirt” that move on their own, you have mites. Mites are usually a problem during hot weather and fall temps should alleviate the problem. Watering with a strong shot of water is the easiest control against mite problems. You can also release beneficial insects like lacewing larvae, parasitic wasps and ladybugs to control an infestation. If you do not want to use mitices, consider using Safer Insecticidal Soap & Sunspray Ultra-fine Spary Oil. Miticides (such as Spectracide Permethrin Insect Control, Bonide Kelthane, Schultz Houseplants and Gardens Insect Spray and others) can be used but follow the instructions on the label; they are best used alternating with other types of pesticides or with soaps and oils (like Safer Insecticidal Soap & Sunspray Ultra-fine Spary Oil). This prevents the mites from developing tolerance to the miticides.
This message was edited Aug 15, 2010 2:08 AM
Thanks so much for your thorough comments Luis. I am pretty sure I do not have mites. There is no leaf distortion at all and no webbing. I have also sprayed the bushes with Bayer combo Disease and Insect Spray as well as neem oil and insecticidal soap throughout the summer (always according to instructions) to battle this issue. My whole yard has been battling fungus/bacteria spots this year. I think my main issue too much sun. When new leaves sprout they come out looking perfect. I am going to look tomorrow to see if I can see a pattern where lower leaves that are shaded by upper ones have less yellowing. If that seems to be the case then I will move them ASAP. I have a good place I can transplant them to where they will get good sunlight but not the 12 hours of it beating down on them that they get now. Thanks again for all the advice.