Hydrangeas, pink and blue

Our blushing Hydrangeas

By Amy McDowell

A Hydrangea’s color is as changeable as a chameleon. You may buy a Hydrangea with sky-blue blooms at the garden center that turns to pink in your garden. It’s a frustrating trait for gardeners intent on designing with a particular color. The Hydrangeas, though, are simply responding to their environment. A low soil pH (acidic) will turn Hydrangeas blue and a high soil pH (alkaline) will turn them pink.

Virtually all of the soils in central Iowa are alkaline. Areas where fallen oak leaves or evergreen needles collect and decay may be more neutral, but it’s unlikely that you’ll find any acidic soils with a pH lower than six in this area. And that means no blue Hydrangeas for our gardens. Plant a blue and it will convert to pink. (The whites stay white regardless of pH.)

Even if you go crazy mulching with pine needles or pouring on Miracid or Aluminum Sulfate, the plant’s response will be both mild and temporary. Not only are our soils alkaline, but our tap water is, too. A blue Hydrangea grown in a controlled environment like a pot is likely to turn pink eventually just because of the water.

So pink or white it is. At least we’ve got choices of bush, tree or climbing Hydrangeas. We can decorate our gardens with mopheads like Annabelle, lacecaps like Radiata, repeat bloomers like Endless Summer and White Moth and ornamental trees like Pee Gee and Pink Diamond. We’ve also got the white lacecap climbing Hydrangea and the deep burgundy fall color of the oakleaf Hydrangea.

Variations in bloom and foliage are ever expanding. Although its not hardy here, the new “Lady in Red” Hydrangea (zones 6-9) is red stemmed and red veined. It’s just a matter of time before hybridizers create something like that for our colder winters.

Don’t be blue when your Hydrangea blushes pink. We all must adapt to our environment.

Fall Color

Raging Red and Flaming Orange

Bold fall colors for your garden

By Amy McDowell

Iowa is blazing with spectacular fall color. You still have time to plant some color in your garden this year. Take a trip to your local garden center and take a look at the vibrant rainbow of warm colors available in trees and shrubs.

Some of the most glorious trees right now are the red and sugar maples decked out in red and orange, and the white and green ashes wearing fall purple and golden yellow hues. Red maples (Acer rubrum) mature to about 40 to 60 feet tall with a rounded canopy. Sugar maples (Acer saccharum) reach 60 to 75 feet tall and tend to be taller than they are broad. Red and sugar maples turn to stunning reds and oranges in the fall. White ash trees (Fraxinus americana) will generally color to royal purple in the fall and green ash (Fraxinus pennsylvanica) will turn vibrant golden yellow. Depending on the variety, ash trees range from 40 to 70 feet tall.

At the garden center, you will find named varieties of maple and ash trees. Named varieties are essentially clones sharing the same genes. The advantage to a clone is that you can be guaranteed genetic traits such as spectacular fall color. Trees grown from seed are genetically diverse and fall color will vary from one plant to another.

If you are thinking about planting shrubs rather than trees, take a look at the intense colors of sumac, burning bush, fothergilla, viburnum, and witch hazel. Sumac (Rhus typhina) is the brilliant red you see along roadsides right now. It is a suckering shrub, so it forms a loose mound about 15 feet tall and about as wide as you will allow it to spread. Burning bush (Euonymus alatus) will stay in bounds at about ten feet high and wide. It is often used as a hedge, and can be kept to a more compact height if you prune it. Fothergilla (F. gardenii) will mature to around four feet and colors to a fiery red-orange-yellow combination in the fall. Viburnums (V. species) are Iowa natives, so they are tough and resilient. To choose a viburnum with great fall color, buy them right now. They turn shades of red and orange, but some species are bold while others are bland. Witch hazel (Hamamelis vernalis) is another red shrub you may see on roadsides right now. It will grow to about eight feet tall and ten feet wide.

Finally, there is the fierce red maple that is too short to be a shade tree, but pretty tall to be a shrub. It is the amur maple. You will see drifts of these along Iowa’s roadways that have been planted by the Department of Transportation. The stunning amur maples (Acer ginnala) often have a multi-stem trunk and grow to about 18 feet tall.

Amy McDowell is an Iowa Certified Nursery Professional. She has an associate’s degree in commercial horticulture and has worked in the field for ten years. She lives and gardens in Polk County.