One of my hydrangeas has a good bit of new foliage. The leaves are bright green as you can see but much paler, more pale (?) than the existing growth. This looks like it needs something. But what?
Where growing - pot or ground?
What is the average pH of soil in your area?
What fertilizer, or other "treatments," have you used/applied?
Looks like the soil pH is alkaline and the soil needs to be acidified. One of those cheap soil pH kits sold at plant nurserties will confirm. The telltale signs are leaves that turn iight green or yellow while the leaf veins remain dark green. Damage to the roots or too much/sudden rainfall can also impair their ability to absorb nutrients and the leaves might develop this look. The solution is the same in either case: amend with aluminum sulphur, garden sulphur, greensand or one of those iron-chelated liquid compounds sold at plant nurseries. The liquids will produce faster results but have to be applied more often. Make a habit of amending the soil regularly to prevent this problem (say in Spring and Fall, for example). Do not overdo it however as high levels of sulphur can burn the roots. I just had to amend mine on Wednesday.
You can also get a kit that checks for nitrogen, phosphorus and pottasium (N-P-K) levels. Nitrogen problems can also change the color of the leaves but the leaf veins ALSO change to the same color. Since your leaves show green leaf veins, I do not think N-P-K Issues are "it". If nitrogen levels are too low, add more in the form of blood meal (a slow release, organic fertilizer high in nitrogen), etc. The leaves will recover unless the soil is not quickly amended.
Too much sun can also turn the leaves a yellowish or whiteish color. The leaves veins ALSO turn the same color. The leaves may eventually feel papery to the touch. However, only leaves in direct contact with the sun would be affected (the ones underneath -protected from the sun- would remain dark green. So I douibt this it "it". The solution is to transplant the shrub eventually (build a contraption to provide shade in the meantime). The leaves scorched by the sun will not recover though.
This is in a raised bed in the ground at the corner of my house. It gets morning sun and is in shade after about 2 PM. I have not amended the soil at all in the past few years. It was damaged by the cold during the winter and did not bloom at all. I cut back the dead stems. I have 4 other large hydrangeas like this one and two are in full sun all day and have not had this dramatic change in color. They do seem a little lighter in color than normal. Only one had a few blooms. I will try using some sulphur. This is a pink bush and I've turned the others blue with aluminum sulfate. We have gotten a good bit of rain this year but weather.com says its only half the normal rainfall this month.
Join the club!!! My Macrophyllas got affected here too. Except for a lacecap that is getting some "extra sulphur" to turn purpleish, and except for a white one (Mme Emile Moulliere), the others (which bloom pink) did not bloom. One Annabelle did not return. A paniculata is doing fine.
Have Annabelle Hydraneas that were planted 3 years ago. This year a few plants are blooming like the "wild hydrangea". Can anyone tell me why the plants are now blooming different? Could it be from the harsh winter or my landscaper cut them a little later this year. Thanks
The flower buds are developed in Spring so winter would not necessarily cause harm. Can you post pictures of the problem that the landscaper caused? and the blooms? I am not sure what you meant.
You said, "amend with aluminum sulphur, garden sulphur, greensand or one of those iron-chelated liquid compounds" . Where would I find one or all of these? I checked at Lowes & Home Depot, but could not find them. I found Ironite, but after reading the various forums here, I'm not sure if I should use it.
Lowes and GD usually have liquid products that help acidify the soil. They go by different commercial names and I usually ask someone at the plant nurseries for "liquid products that will help acidify the soil". Some brand names are Ferti-lome, Liquid Iron, Dr. Iron (you can safely assume by now that many have the word "iron" in them (LOL). Sometimes they add the word chelated, most times they do not. Try smaller plant nurseries if your nearby Lowes/HD are out.
In a pinch, you can get a aluminum sulfate/ammonium sulfate/garden sulphur or even add a cup of vinegar to a gallon of water. Vinegar is useful but degrades quickly in the soil.
Do not forget to amend regularly once you see what amounts and how-often they work for you. You will need to continue amending in future years as unamended soil tends to revert to its original acid-neutral-or-alkaline state.
Here is a link that might be useful: Example of one of them
Thank you, Luis. I will try to look for them. I just tried the vinegar solution this morning. *Fingers crossed*
I saw one bottle at Blooming Colors in Grapevine. If you are in Dallas, call Northhaven Gardens or Nicholson Hardie. In prior years, I have bought aluminum sulfate, ammonium sulfate and ison sulfate at The Plant Shade as well.I think I have seen bottles of Ferti-lome there too before.
This post was edited by luis_pr on Tue, Jul 22, 14 at 15:00
The photo reminds me of a chlorosis. That is where the veins remain green and the leaves are pale green. Try dousing the plant with some Ironite according to the bottle's directions. See if that greens up the leaves.