Extension Educator, Horticulture
Ever notice how your eyes are drawn to big things? We can use this in our landscape design when creating focal points. The best landscapes draw the eye through the landscape by using well spaced focal points. Shrubs with big leaves and/or big flowers can serve as focal points or specimen plants. If you are looking for a well-endowed shrub that screams "hey look at me!" than hydrangeas are for you.
Most people are familiar with Smooth hydrangea, Hydrangea arborescens. This plant has bellowed its presence in many landscapes for years. The large heart shaped leaves are 2-8 inches long and 2-6 inches wide. The summer flowers are also large at 4-6 inches in diameter. Their colors go from green to white to brown. Notice I didn't say pink or blue. This is not the litmus paper hydrangea. For nice dried flowers cut fading flower heads off, strip the leaves and hang upside down. Once dry, the heads can be left as is or spray painted your favorite decorator color.
'Grandiflora' is a common cultivar of smooth hydrangea and is often sold as 'Hills of Snow.' Flowers are large but often spread open. 'Annabelle' is a better cultivar. She has U of I roots since past professor J.C. McDaniel selected 'Annabelle' for her large symmetrical flowers and more erect growth habit. 'Annabelle' flowers about 2 weeks later than 'Grandiflora' and puts on a flower show for 6-8 weeks.
Smooth hydrangea can flop as flowers develop. Since smooth hydrangea blooms on new wood, it can be cut down close to the ground in early spring to control floppiness.
I often get the question "Why doesn't my hydrangea bloom?" Usually the answer lies in the species of hydrangea and whether it blooms on new or old wood. Many people purchase Bigleaf Hydrangea, Hydrangea macrophylla to get the pink or blue flowers. Bigleaf has many cultivars and unfortunately many die to the ground each winter. Bigleaf blooms on old wood from the previous season. If the stems die to the ground during winter or are pruned in late winter or early summer then no flower buds are formed. If any pruning is needed it should be done immediately after bloom or in late August. Common cultivar is 'Nikko Blue' (blue in acid soil).
Panicle hydrangea, Hydrangea paniculatea is a tough plant that blooms later than smooth hydrangea. The creamy white to pink flowers usually start in July. 'Tardiva' and 'Pee Gee' are the most common cultivars. It blooms on new wood and should be cut to the ground every few years.
Oakleaf hydrangea is an interesting plant with four season appeal. Climbing hydrangea is probably one of the best hydrangeas and certainly one of the best vines. Check out http://woodyplants.nres.uiuc.edu/ for pictures.
Hydrangeas are fairly adaptable and generally trouble free. They grow best in rich moist soil with partial shade in the afternoon. They suffer under drought and watering may be needed. With flower color be sure to select a cultivar of the particular color and then spend time amending the soil before planting. Aluminum sulfate is used to lower pH for blue flowers. Get a soil test to determine the proper amount.
Hydrangeas are summer bloomers when few other shrubs bloom. If you are looking for pinks or blues, best luck is with 'All Summer Beauty' and 'Endless Summer' since these bloom on new and old wood.
There are many cultivars and species of hydrangea. Do your homework to get the flower color, size and winter hardiness you desire.