Hydrangeas: Changing Color and Blooms

Donna in Massillon asks,  ‘I have hydrangea bushes that are just loaded with buds. I also have a hydrangea tree. It doesn’t have a bud on it at all. It’s in a good amount of sunlight, I fertilized it in the spring, and it’s in its second year.’

So, the hydrangea trees are in the paniculata family, and they actually flower a lot later than some of the other varieties of hydrangeas. So, most of our hydrangea trees at the nursery are just starting to set bud now. A lot of them haven’t started yet. 

There’s a variety called Quickfire that’s already starting to bloom. Now, Quickfire is the fastest blooming of all the hydrangea tree forms. Then there’s another one called Vanilla Strawberry. It’s starting to set its buds. That’s what I have. The ones we have at the nursery are literally just starting to set their buds now.

Generally, the things in a container above ground are going to be about a week to 10 days ahead of the stuff in the ground. So, it would be very normal that your tree would not have the buds set just yet. But it will set its buds here in the next two weeks. The flowering should start sometime in July and flower probably through September.

There’s a couple different ways you could go there, but I prefer the all-season fertilizer. It’s a green pelletized fertilizer. It will feed the plant for six months, and so you don’t have to do it multiple times. It’s kind of a one and done.Occasionally adding some coffee grounds to it creates acidity in the soil, which hydrangeas do like, and it also has a lot of iron in it, and that iron will cause a really rich, dark green leaf. It’s a great organic way to amend the soil and get rid of your coffee grounds.

If we do get crazy hot here in the next week, which it does look like that’s going to happen, and the plant looks like it’s starting to wilt a little bit, just give it a little moisture.

It’s still not fully rooted if it’s only in the second year. It’s significantly better than it was last year, but it is going to still need some help to get through the summer if we get into some really hot, hot temperatures. So, doing a little bit of watering on that next week when we get into the mid to high 90s would be good.

If we had this same conversation last year, we had a very warm May last year. Once we got done being cold, we went right to 90. There wasn’t much of an in-between. And this time last year, that same tree would have had buds set on it. So, it’s a temperature,

timing kind of a thing. But you’re on the right track. You’ve done what you need to make the plant produce the flower blooms, and they should be showing up here in the next 7 to 10 days. 

I wanted to get to talking about changing the color of hydrangeas. I know that’s something we get asked a lot about. Not all varieties of hydrangea can their color be changed. I think that’s the first place we need to start. 

There is a specific variety of Macrophylla hydrangea. Probably the most common by far would be one called Endless Summer. Endless Summer, the flower can be pink or it can be blue, depending on the soil acidity. When the soil pH is really acidic, it allows the plant to absorb aluminum out of the soil, and it makes the flower blue.

When the soil is sweet, or if you add lime to the soil, it cannot absorb the aluminum, and then the flower is pink. I think our soil is more naturally alkaline. It is a sweeter soil. If you want them blue, you have to do something. 

When I go out and do the purchasing in Oregon, their soil is really acidic. All of the hydrangeas are this beautiful powder blue color, and everybody wants theirs to be pink. And here, we’re naturally pink, and everybody wants them blue.

That’s a great point. We sell a product called Aluminum Sulfate, and we sell another one called Garden Sulfur. Both will create acidity in the soil and will allow the hydrangeas to become that blue color. It’s something that does need to be added more than once generally, because you do want to create that acidity in the soil.

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