Hydrangea help?

[LaydeeBug]

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]

1. Pruning hydrangea is a bit more complicated than most flowering shrubs, IMO

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]

8. Thanks for that link because I am really confused about cutting them.

Great article!

[elleng]

2. 'For true blue flowers, the hydrangeas need to be grown in acidic soil

(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]

3. I keep reading that but the plant that i'm positive is a hydrangeas always has white flowers.

The native soil (Charlton/Canton Sandy Loam) in the New England uplands is usually 5.5 PH.

[csziggy]

4. Could you have an oak leaf hydrangea?

Those are always white.

https://en.wikipedia.org/wiki/Hydrangea_quercifolia

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:

Flower color in H. macrophylla is dependent on cultivar and aluminum availability. Aluminum is necessary to produce the blue pigment for which bigleaf hydrangea is noted. Most garden soils have adequate aluminum, but the aluminum will not be available to the plant if the soil pH is high. For most bigleaf hydrangea cultivars, blue flowers will be produced in acidic soil (pH 5.5 and lower), whereas neutral to alkaline soils (pH 6.5 and higher) will usually produce pink flowers. Between pH 5.5 and pH 6.5, the flowers will be purple (see image at left) or a mixture of blue and pink flowers will be found on the same plant.
http://www.usna.usda.gov/Gardens/faqs/hydrangeafaq2.html#How-change-flower-color

[NutmegYankee]

5. I think it's the normal variety

I don't think there is an aluminum deficiency as the neighbors all have blue flowers.

[csziggy]

6. That looks like the classic moptop but I think there are white varieties

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]

7. Looking at images, I think it's the "Annabelle" cultivar of wild hydrangea.

The flowers are fertile and of a uniform height, slightly flattened and displayed atop sturdy stalks. When they open, they are slightly green. The color changes to creamy white as they mature and then to brown as they wilt. Don’t try to change the color by changing the acidity of the soil; this species of hydrangea does not alter the blossom shade according to soil pH.

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.

[LaydeeBug]

9. All white hydrangeas will always stay white, regardless. nt