I would like to know about the success of growing Peegee hydrangea in this part of Colorado. I have not seen any in yards in the five-plus years we have lived here. When is the best time to plant them? Full sun or part shade? Fertilizers and mineral amendments to the soil of the planting site?
The hydrangea most people think about is a species call bigleaf hydrangea (Hydrangea macrophylla). This is the plant with the big rounded flower clusters that can change from blue to pink depending on soil acidity. And though some varieties of bigleaf hydrangea can grow here, this plant prefers cooler, more humid weather with a rich, organic, well-drained, somewhat acid soil, which takes some careful preparation and siting of the plant.
However, Peegee hydrangea (Hydrangea paniculata) is a different animal and tends to grow here with little fuss. To tell you the truth, I was overly cautious with this plant for a lot of years, recommending it be planted with some afternoon shade. And though it will do great with half- day shade, it doesn't require it.
I started experimenting with them eight or 10 years ago by planting some in full, hot sun and, wonder of wonders, they thrived! In fact, they did better than some that are in full shade.
However, there are still several things you should do when you plant. First, thoroughly amend the soil around the plant by mixing in generous amounts of low-salt, decomposed organic matter such as Soil Pep. As a container plant, they can be planted any time of the year as long as you can dig a hole in the ground.
Second, water them regularly. They like a regular supply of water, but don't keep them soggy all of the time.
Third, hydrangeas as a group are heavy feeders so plan to fertilize them every spring with our Bookcliff Gardens Choice Professional Turf Food or with Miracle Gro.
Fourth, mulch them well with a 2–3-inch layer of mulch on top of the soil around the plant.
One difference you may notice here is that Peegee hydrangea doesn't get as big as it does in other parts of the country. They can form small trees back east, but around here you can expect most of them to top out at no more than 5 or 6 feet tall.
The past 10 or 12 years there has been an explosion of new varieties of this plant being offered for sale. One characteristic the plant breeders are selecting is color in the bloom.
Peegee hydrangea has a long, conical or football-shaped cluster of pure white flowers from early to late summer. However, some individual plants start out with white flowers that fade to rose pink as they age. These are the plants that breeders are looking for.
We have a group of Peegee hydrangea in our yard called "Pinky Winky." They are, without question, my wife's favorite plant in our yard. (And we have a LOT of plants in our yard!)
The individual flowers in the cluster open first at the bottom of the cone, working up toward the tip over a month or so of bloom. Those older, lower flowers turn pink while the newly opened flowers at the tip are pure white, giving a lovely two-toned effect that lasts for several weeks.
As summer wanes and fall comes on, the flowers turn a buff brown and hang on the plant all winter, giving some interest to the garden when not much else is going on.
My wife has brought them indoors many times as cut flowers or for table decorations at Thanksgiving and Christmas.
Will "Pieris japonica" do well in our area?
Pieris, also known as mountain laurel, really doesn't have much of a chance here.
Most of them are winter hardy enough for our area, but they like a cool, humid environment with a rich, very acid, well-drained organic soil. We have NONE of that! We have exactly the opposite of that.
They're related to heathers and heaths that are practically impossible here.
They truly are a lovely plant, and if you want to try them, there are several things you'll need to do.
First, plant them in bright shade (to help cool them), surrounded by other plants (this helps raise the humidity). Before planting, you'll need to mix in an abundant amount of well-decomposed organic matter such as peat moss, Soil Pep, and/or compost. Mix it in at least half and half with the native soil. Mix it in 12–18-inches down and do a big wide area around the plant.
You might even consider planting them in a large pot (the larger the better) filled with a good potting soil. It also will help to mulch the plant well after planting.