OK. So I have been reading in the forums about being able to alter the color of your Hydrangeas. I had no idea you could do this. Mine are just plain white. What could I do to get different colors? I have 2 plants that are older. They have been here for the 8 years we have been here and I have no idea how long before then.
Thanks
-
luis_pr
- Greener Thumb
- Posts: 824
- Joined: Sun Jul 05, 2009 8:31 am
- Location: Hurst, TX USA Zone 7b/8a
Macrophyllas that bloom blue/purple/pink shades can alter the color of the blooms if you change the acidity of the soil. This acidity can be measured using the pH Scale. When the reading is below 7.0, the soil is considered acidic. When greater than 7.0, the soil is considered to be alkaline. When exactly 7.0, the soil is considered to be neutral.
You get blue-ish blooms when the soil is acidic. It varies based on the variety but generally speaking, you start to get blues around a reading of 6.5 or less. Readings above that will result in pink blooms. Readings near 6.5 to 7 will sometimes yield purple.
If interested in a given color, sometimes it pays to get a variety known to produce that color well.
Purple is the hardest to get because it occurs in a small sliver of the pH scale and then again, not exactly the same sliver for all varieties. Red is "not available" in hydrangeas because they lack a red pigment; you can only get shades of pink. Examples of good blues can be seen in Blue Deckle, Blue Bird and Nikko Blue, etc but note that some hydrangeas will resist turning blue (Alpengluhen. Ami Pasquier for example). Good reds: Alpengluhen (aka, Glowing Embers), Masja, Fasan, etc
The pH Scale is logarithmic so changes in numbers may be small but the change in soil acidity is large. Soil that used to be 7.0 and changed to 6.0 is 10 times more acidic than it used to be.
There are many soil acidity measuring kits sold out there. The cheap ones will yield a color that gives you an idea of what the soil acidity is. You mix soil + water + a pill, wait and then compare the color to a table of sorts. Usually close enough for government work but not that accurate. More expensive ones give results in the pH Scale.
To acidify soil where your pink blooms come out blue, you have to add amendments to allow the hydrangea to absorb aluminum. If your soil is not lacking naturally occurring aluminum, you can use garden sulphur, green sand, liquid iron-chelated compounds, etc. If your soil lacks aluminum (a soil test can tell you) then aluminum sulfate is a better choice. Do not use aluminum sulfate near rhododendrons or azaleas; it can kill then in high enough dosages. Apply at the rate recommended by the product label; too much and a/s can damage the fibrous roots.
To get pink blooms when your blooms normally come out blue, add some lime to make the soil less acidic. Again, use the product according to the label directions.
White blooms cannot be changed to any other color. Some of the new Annabelle "clones" that bloom pink cannot be changed to white or blue; if you try, they will turn a different shade of pink instead.
Remember that as your blooms age -regardless of color- they will not stay that color forever. Instead, the blooms will alter their color in a certain progression unique to that variety of hydrangea. For example, pink blooms in one variety might turn greenish/pink, then sandy and finally brown.
Altering the soil acidity is difficult when the plant is in the ground. One side may change more than another side, for example. It is far easier to change blooms colors when the hydrangea is potted.
Does that help you, MaryT?
Luis
You get blue-ish blooms when the soil is acidic. It varies based on the variety but generally speaking, you start to get blues around a reading of 6.5 or less. Readings above that will result in pink blooms. Readings near 6.5 to 7 will sometimes yield purple.
If interested in a given color, sometimes it pays to get a variety known to produce that color well.
Purple is the hardest to get because it occurs in a small sliver of the pH scale and then again, not exactly the same sliver for all varieties. Red is "not available" in hydrangeas because they lack a red pigment; you can only get shades of pink. Examples of good blues can be seen in Blue Deckle, Blue Bird and Nikko Blue, etc but note that some hydrangeas will resist turning blue (Alpengluhen. Ami Pasquier for example). Good reds: Alpengluhen (aka, Glowing Embers), Masja, Fasan, etc
The pH Scale is logarithmic so changes in numbers may be small but the change in soil acidity is large. Soil that used to be 7.0 and changed to 6.0 is 10 times more acidic than it used to be.
There are many soil acidity measuring kits sold out there. The cheap ones will yield a color that gives you an idea of what the soil acidity is. You mix soil + water + a pill, wait and then compare the color to a table of sorts. Usually close enough for government work but not that accurate. More expensive ones give results in the pH Scale.
To acidify soil where your pink blooms come out blue, you have to add amendments to allow the hydrangea to absorb aluminum. If your soil is not lacking naturally occurring aluminum, you can use garden sulphur, green sand, liquid iron-chelated compounds, etc. If your soil lacks aluminum (a soil test can tell you) then aluminum sulfate is a better choice. Do not use aluminum sulfate near rhododendrons or azaleas; it can kill then in high enough dosages. Apply at the rate recommended by the product label; too much and a/s can damage the fibrous roots.
To get pink blooms when your blooms normally come out blue, add some lime to make the soil less acidic. Again, use the product according to the label directions.
White blooms cannot be changed to any other color. Some of the new Annabelle "clones" that bloom pink cannot be changed to white or blue; if you try, they will turn a different shade of pink instead.
Remember that as your blooms age -regardless of color- they will not stay that color forever. Instead, the blooms will alter their color in a certain progression unique to that variety of hydrangea. For example, pink blooms in one variety might turn greenish/pink, then sandy and finally brown.
Altering the soil acidity is difficult when the plant is in the ground. One side may change more than another side, for example. It is far easier to change blooms colors when the hydrangea is potted.
Does that help you, MaryT?
Luis
Yeah.luis_pr wrote: Altering the soil acidity is difficult when the plant is in the ground. One side may change more than another side, for example. It is far easier to change blooms colors when the hydrangea is potted.
I have a Nikko Blue that has blooms that range from pink to purple, to blue.
Some of the individual balls of blooms even have a rang of colors to them.
I actually like it better that way, than having the whole plant one color.
Especially now that it is about 5' tall and 4' across.