My soil hasn't been tested, but I know that it is quite acidic, as I think most of the gardens in these parts are. A dark pink hydgrangea I planted a few years ago is now dark blue-purple for me. That one doesn't bother me, but what does bother me is that my Blushing Bride hydrangea was actually light blue this year. It didn't look like a white hydrangea at all.
I've read that white hydrangeas don't turn color no matter what kind of soil you have, but that doesn't seem to be the case with mine. In the same bed, I have Twist and Shout, which was also quite blue this year. I would like to try adding lime around those two to see if I could make them at least a little less blue....hopefully bring Blushing Bride back to a neutral white?
I have no idea how to apply lime or how much to use. Recommendations I see are pounds per square feet, and that's difficult for me to measure/ break down since I'm only talking about treating two shrubs and don't have a scale to weigh anything. Also, would I have to remove the mulch or could I put the lime on top and water it in? I know it's also recommended to get the soil tested to get a ph number, but frankly I wouldn't know what to do with the number even if I knew it. I just want to take some of the blue out of these two hydrangeas!
How to use lime to change color?
First, lime takes quite a while to work. Two applications a year would be the usual application: one cup in spring and one in fall and spread it (on top of the mulch is fine) out to the drip line.
Ercane usually recommends keeping pink hydrangeas potted in a large nursery pot , then planted in the garden, to prevent the soil from taking up the ever present aluminum, which turns them blue, due to the acidity present in most Northeast soil.
I don't know if lime can change Twist and Shout or Blushing Bride but Ercane should arrive and can shed some light on it for you.
The presence or absence of aluminum doesn't matter if the pH is high--in order to be blue, hydrangeas need both low pH and aluminum. If the soil pH is high, the plant can't take up the aluminum that's in the soil so they will be pink. So you can definitely add lime to your soil and turn your hydrangeas pink, but how much you need will depend on how acidic your pH is now. And over time your soil will always drift back to its natural acidic state unless you keep amending. So if your soil is quite acidic you may find it easier to keep them the color you want if you plant them in a container as pirl mentioned--it's much easier to control the pH there than it is in the ground.
Blushing Bride by the way is not a true white hydrangea--if your soil is alkaline enough it'll be pale pink (which I think is where the name "blushing bride" came from) and if it's acidic enough it'll be pale blue. If you're right around neutral maybe you'd get something that looks a little closer to pure white but I think it'll be a fine balance. If you look at the pics in Plant Files most of them show it with either a bit of blue or a bit of pink color to it: http://davesgarden.com/guides/pf/go/159492/
I moved Blushing Bride this year and it was a BIG job....I could never lift that one to get it into a container, I'm afraid. But the color does bug me...it's a real icy blue and I find it just doesn't look good with anything else. Looks much bluer than anything in the plant files. It's actually better now that the blooms have started greening up. My mom visited this year and asked what happened to my "white" hydrangea.
I could maybe lift Twist and Shout and put it into a container, but don't have the space to overwinter it anywhere. The only thing I can think of would be to plant it in one of those Agroliner bags and then put that back into the ground. But those are porous, so I don't know if the acidity of the surrounding soil would still leach into the grow bags and keep it blue. Unless I just bury a big plastic container? I might actually be able to get one of those from a local tree nursery. Do you think it would drain ok in the winter if permanently planted in one of those? How big a container do you think it would need? I don't mind if it won't get huge in a container, either, as long as it still does well.
If they're that big then it's probably worth trying to add some lime to your soil. Especially since it sounds like you just want things a little less blue rather than trying to get them all the way to pink it may be manageable--you'll just have to keep after it regularly. Or you could learn to love them the color they are--out here we have alkaline soil so I've just learned to like pink hydrangeas, and plant things with them that will complement the pink color. For me it would just be too much effort to have to keep amending the soil all the time to make them blue even though I like the blue color a little better.
If you want white or white that goes a bit pink with age (regardless of soil pH), you might look into cultivars of H. arborescens and H. paniculata instead. They are not sensitive to soil pH. Most start off with white blooms, and some cultivars age to pink. They also have the advantage of being hardier than the macrophyllas and they bloom on new wood so you don't have to worry about when you prune them or having to protect them over the winter.
I didn't protect any of my hydrangea this year and they all bloomed....even the non endless summer type one. That got to be far too much work! The problem is that I don't have a lot of room, and I think even Blushing Bride may end up being too large if it keeps going at this rate. Aren't those other varieties much larger? I'm intrigued at the notion of putting Twist and Shout into a sunken pot if that will help keep it more compact, however. I actually left Twist and Shout in a small pot all winter, completely unprotected, and it survived and bloomed.
And yes, I'm more concerned with making things a tad less blue rather then completely changing the color. Because it seems like things just get more and more blue each year. I've had Blushing Bride for several years and this is the first year it's been so blue. If it was a matter of spinkling some lime one or twice a year on top of the mulch, that doesn't sound like too much work. I'm way too lazy to be moving and replacing mulch that often, though!
This message was edited Aug 8, 2010 12:38 PM
This message was edited Aug 8, 2010 12:52 PM
I'd go ahead and try the lime and see if it gives you the results you want. It wouldn't hurt to get your pH tested first though so you know how far away you are from neutral--the more acidic your soil the more lime you'll need to add before you can really see a difference.
As far as the other types of hydrangeas--I can't think of any small H. paniculata cultivars, but there are some H. arborescens cultivars that are supposed to stay in the ~4 ft range. Make sure you research the individual cultivars before buying though since some of them get larger too.