Soon it will be July, and one of our favorite shrubs will be in glorious bloom. Can you guess? I recently came across a Garden Center pricebook from 1982 and there was one hydrangea variety available! Five years later we had three. Fast forward to 2025 and we started the spring allocations with more than twenty. The hybridizers have created hardier and more adaptable plants with bigger and more varied flowers. So if you want to plant hydrangeas in your yard, there is a type that will be perfect for you. Let’s look at each type specifically.
Smooth hydrangea, H. arborescens, is still one of the easiest of the group. As this type reliably blooms on new growth, it can be pruned to the ground in late fall or very early spring. ‘Annabelle’ with its huge creamy white flowers set the standard for decades, but there are some new kids on the block. Check out ‘Incrediball’ and ‘Flowerfull’. Plant smooth hydrangeas in shady, moist spots and they’ll blossom every summer.
Bigleaf hydrangea, H. macrophylla, used to be a lot trickier. Older varieties like ‘Nikko Blue’ flowered from buds set the previous summer, necessitating protection from winter wind and cold temperatures. Many gardeners had bags of bark mulch in their garages, waiting for the ground to freeze before mounding their plants. The switch was flipped in 2004 when ‘Endless Summer’, a bigleaf that promised blooms on new growth entered the market. And though it was less reliable than expected, ES did set the stage for new cultivars like ‘Summer Crush’ and ‘Bloomstruck’.. that do deliver on the promise. Nothing has changed in the siting requirements though, so remember that bigleaf hydrangeas do best with 3-4 hours of morning sun and even moisture.
Before we continue, let’s answer that age old question: How do I make the flowers blue? Some, but not all, varieties of bigleaf hydrangea will have flowers that vary in color from pink to blue. This color change is affected by the amount of iron in the soil. Our high pH soil restricts the plants’ ability to access the available iron. To have blue flowers requires a change in acidity. Acidic fertilizers applied to the plant have a short-term benefit. Apply granulated sulfur to the soil around to base of the Hydrangea each spring and fall to achieve a nice purple blue. Or take comfort in the certain fact that gardeners on the east coast are raising their soil pH so that the bigleaf flowers are pink!
Panicled hydrangea, H. paniculata, is the only Hydrangea that will grow successfully full sun. The flower heads are elongated rather than round, and creamy white in color. As the flowers mature, they often change in color to a deep pink. ‘Vanilla Strawberry’ has an especially vivid color change. When choosing varieties, be sure to check the descriptions. Panicled hydrangeas used to be quite large, and some cultivars still are, but smaller types have been introduced for smaller gardens. Check out ‘Bobo’ and ‘Little Quick Fire’. And if you’re looking for an adaptable ornamental tree for a smaller spot, many panicled varieties are available in a single-stemmed tree form!
Oakleaf hydrangea, H. quercifolia, is similar to the bigleaf types. Winter protection is a must if you want flowers, but the larger size of the plants can make this difficult. But who cares about flowers when the lobed leaves and stunning burgundy fall color make the blossoms a bonus? ‘Alice’ has a lovely elongated flower head and ‘Jetstream’ is a more compact plant. Oakleaf hydrangeas prefer several hours of morning sun and are less prone to wilting in the heat.
So add a hydrangea or two to your garden for show-stopping flowers at a time when many other shrubs are looking a bit tired.