cercospora leaf spot on on hydrangea

Our newly planted oakleaf hydrangea (very small from a 3 inch pot!) was doing great until it developed cercospora leaf spot on a couple of larger leaves. I removed the diseased leaves, but following a heavy rain, several more of the upper leaves were infected. I removed these and decided to spray with Immunox fungicide. After 2 treatments, every leaf on the plant is heavily infected and no more new growth. Does anyone know why the Immunox didn't work? Thanx from Pittsburgh

bmurtagh185, there's some information here: http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf. Sounds like you've done what is suggested (Immunox) - the only other thing you could try is cut the plant back 50% to promote new growth.

Debbie

Can I hijack this thread with a related hydrangea question? I bought a Woodlander Hydrangea last summer, which lived in a pot until now. It bloomed stunningly earlier this year. Ever since then, the leaves have been very limp. I tried moving it to a bigger pot, and watered it daily. Yesterday planted it in the ground to see if that would help, but the leaves are still limp. Is this a disease? Will it get better?

Happy, it sounds like what you might have is the grub of the Black Vine Weevil chewing on the root system/crown of the plant. A wilting plant that is not dry is a dead giveaway that 'something' is eating on the plant. What I would do is lift the plant and examine the old potting soil that I assume would still be intact from when you transplanted it into the ground. Carefully 'open up' and examine the interior of the ball of potting soil. Look for a small grub, approximately 1/4"-1/2" long, oftentimes it does look just like a piece of perlite. Typically there are only one or two grubs. Kill them and then replant. It should recover just fine. Of course, they may have really eaten away at the interior of the crown and/or root system. You should be able to see evidence of where they have been chewing. Good luck!

Debbie

Thank you! Thank you! I'll do that this evening.

Debbie: I probably put that poor hydrangea out of its misery. I really dissected its roots looking for grubs, but didn't see any. I washed the roots off, dipped the poor thing in a weak bleach solution, rinsed it and repotted it in new Pro-Mix, cut back its branches and put a big plastic bag over it for a mini-greenhouse. Gave it a drink of Superthrive. It was heading for death anything, so I guess I won't feel too terrible if it croaks (that's not true -- I'll feel awful), but my fingers are crossed hoping for the best.