Gardening
Related: About this forumHydrangea help?
My Big Daddy hydrangea is sort of spreading and I want it to be more bushy and robust.
When can I trim it? What's the "old wood, new wood" thing?
Will rusty nails really make it turn blue? (because it's a Big Momma Hydrangea now)
Major Nikon
(36,900 posts)The reason being that they will usually bloom just fine with no pruning whatsoever, and maybe even better if you aren't pruning them correctly as they bloom quite well on old wood. However, many of the same rules apply that work for pretty much all flowering shrubs, such as deadheading, removing crossing branches, and clearing out dead and dying wood.
Here's a good cut-to-the-chase article from a true master that I think makes a lot of sense for developing a good strategy.
http://ucanr.edu/datastoreFiles/268-86.pdf
Can't help you with the rusty nails thing. Iron deficiency can be a problem, and I suspect there are better soil additives that can be used at least in the short term, but I've never tried using nails.
glinda
(14,807 posts)Great article!
elleng
(136,055 posts)(pH 5.5 and lower). For pink flowers, the plants need neutral to alkaline soils (pH 6.5 and higher). For purple blooms (or a mix of blue and pink flowers on the same plant), the pH of the soil must be 5.5 and pH 6.5.
http://www.bhg.com/gardening/trees-shrubs-vines/shrubs/how-to-get-blue-hydrangeas/
I trim mine (only my 2d year 'renting' an old plant) spring by cutting the old, dry stuff. Looks pretty good.
Have fun!
NutmegYankee
(16,308 posts)The native soil (Charlton/Canton Sandy Loam) in the New England uplands is usually 5.5 PH.
csziggy
(34,189 posts)Those are always white.
There are some varieties of Hydrangea macrophylla that were selected to be white and are never a color. And there are varieties whose color is static and not dependent on soil chemistry.
For the varieties that do change color there needs to be aluminum in the soil:
http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html#How-change-flower-color
NutmegYankee
(16,308 posts)I don't think there is an aluminum deficiency as the neighbors all have blue flowers.
csziggy
(34,189 posts)That were developed from it - check the links in my previous message. With white versions you will not be able to get them to turn color. If you want a blue or pink, you may have to buy another hydrangea.
NutmegYankee
(16,308 posts)Read more at Gardening Know How: Smooth Hydrangea Care: Learn About Wild Hydrangea Shrubs http://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/smooth-hydrangea-care.htm
That is exactly how the flowers change color. It also explains the hardiness of my plant to a New England USDA zone.