Big, Bold Hydrangeas
Hydrangeas have become popular because they're big, they're bold and they show a lot of color around the whole landscape garden area, says hydrangea expert Bob Miller.
The two fundamental types of hydrangea are the mophead (the most familiar big-leaf variety) and lacecaps, which derive their name from the sterile flowers surrounding fertile flowers in the center of each flower cluster.
To turn hydrangeas pink or blue, it's simply a matter of an amendment. Adjusting the soil pH (the measure of acidity or alkalinity in the soil) will change the color of many hydrangea blooms. For pink, raise the pH using limestone, and for blue, lower the pH using elemental sulfur. Depending on the aluminum sulfate that is used or the acidity of the soil, pink hydrangeas can be turned purple or blue. However, that also depends on the variety. Some varieties are resistant to any color change, but if you want to experiment, container plants respond to color manipulation easier than landscape shrubs.
Potted or planted, hydrangeas require excellent soil drainage to thrive. Miller recommends making the planting hole bigger than the plant in addition to using a loose, pliable soil with lots of organic matter. Plant no deeper than one inch above the original pot height. Hydrangeas like cozy spots that get morning sun and afternoon shade.
Once your hydrangea takes off and starts blooming, odds are, you'll want more. "Propagating hydrangeas is very easy if you use the layering technique," says Miller. Look for a shoot that's low on the plant or a few inches down the stem. Cut halfway through the stem on a diagonal, then bend the stem back a little bit. The growth regulators will accumulate at the cut section and make it easy for that plant to root.
Pin the cut area down into the soil and cover with soil. In three to four months, the shoot will have developed a nice root system. Just cut it from the main plant and pot it up. Young plants can be encouraged to branch out nicely by pinching out some of the new growth. Miller pinches back his plants by taking out the very soft tip. "We also take two leaves because that allows for more uniform branching."
Once hydrangeas are established in the yard, they require little maintenance except for removing spent flowers. The main thing to remember about hydrangeas is pruning. Hydrangeas flower on year-old wood. That's true of most hydrangeas, although wild and Peegee hydrangeas flower on the current season's growth. They're deciduous, so in the late fall when all the leaves have fallen, cut back every other shoot to maintain a smaller shrub.
Cut Flower Arrangements
If your hydrangea blooms wilt soon after you cut them, take a bucket of cool water along the next time you go into your garden. Drop the stems into the water right after you cut them. Back in the house, boil some water and let it cool for about a minute. Re-cut the hydrangea stems to the length you want, and pop them into the hot water for 30 seconds. Now put the stems in room temperature water and arrange as desired.
Leaves, But no Blooms?
Lots of leaves, but no blooms? You probably over-fertilized your hydrangeas. Once in early spring and again in late summer/very early fall is enough (Northerners can usually fertilize just once, early in the growing season.) Use a time-release fertilizer or a balanced fertilizer like 10-10-10.
Great Plant Combos
Hydrangeas make a beautiful backdrop. Combine them with peonies, sweet potato vines, Russian sage, begonias, viburnums, catmint, butterfly bushes, impatiens, hostas and any other flowers or foliage plants that like the same growing conditions. If necessary, keep your hydrangeas in shade or part shade, behind plants that need more sun.
"If you don't want a small plant and you want a big plant in the landscape to fill up space and make a lot of color, it's not necessary to prune it," says Miller. "Just let it grow."
Plant breeders are hard at work developing more bi-colored and clearer white varieties for gardeners who hunger for hip hydrangeas. Another popular type, the oakleaf hydrangea, is also easy to grow.