Garden hydrangeas (Hydrangea spp.) are grown for their showy blooms, but not all varieties have a fragrance to go with the flowers. For a sweet scent as well as beautiful flower clusters, plant climbing, oakleaf or panicle hydrangea. To ensure the best blooms, make sure you plant each hydrangea species in the right growing conditions and prune at the correct time of year.
Climbing hydrangea (Hydrangea anomala petiolaris) has lightly fragrant, creamy white flowers born in flattened clusters 6 to 10 inches wide. It is hardy in U.S. Department of Agriculture plant hardiness zones 4 through 8 but grows best in USDA zones 4 through 7. The cultivar "Miranda" (Hydrangea anomala petiolaris "Miranda") has attractive variegated foliage as well as scented flowers.
This hydrangea will grow in full sun or partial shade and prefers locations with afternoon shade. Afternoon shade is particularly important when growing climbing hydrangea in zone 8. The best locations for climbing hydrangea also have well-drained soil rich in organic matter. Water often enough to keep the soil moist but not soggy. Climbing hydrangea is slow to establish but can eventually grow 60 to 80 feet tall and requires a strong support for the climbing vines.
Oakleaf hydrangea (Hydrangea quercifolia) is hardy in USDA zones 5 through 9. It bears fragrant flowers in cone-shaped clusters that can reach up to 12 inches long and 4 inches wide. The flowers start out white, then turn pink and purple. This hydrangea prefers partial shade conditions and cool soil that is kept moist but not soggy. As with other hydrangeas, fertile, well-drained soil is best. Mulch after planting to help keep the soil cool and moist.
Oakleaf hydrangea is a shrub that typically grows 6 to 8 feet wide and high, though some cultivars may reach 12 feet if not pruned. For a more compact option, plant the cultivar "Pee Wee" (Hydrangea quercifolia "Pee Wee"), which grows 3 feet tall and wide.
Panicle Hydrangea (Hydrangea paniculata) has strongly scented flowers in cone-shaped clusters that average 8 inches long and 6 inches wide. The flowers start out white, then turn pink. This shrub is hardy in USDA zones 3 through 8. It reaches 6 to 20 feet tall, depending on the cultivar. The cultivar "PeeGee" (Hydrangea paniculata "Grandiflora") has a particularly sweet scent. This variety grows up to 20 feet tall and can be trained as a small tree.
Panicle hydrangea prefers more sunlight than the other two fragrant hydrangeas but still does best if planted in a location with afternoon shade. It grows best in well-drained, organic soil that is kept moist. Mulch around the base of the plant to retain moisture and cool the roots.
Pruning for Flowers
If you want to enjoy the fragrance of hydrangea flowers, you have to make sure you prune hydrangeas at the right time for each species. Pruning at the wrong time of the year can actually prevent flower formation. Climbing hydrangea flowers on old wood, so prune after flowering if you want to trim the vines. This gives the plant time to set new growth before next year. Oakleaf hydrangea also flowers on old wood and should be pruned right after flowering. Panicle hydrangea, on the other hand, flowers on new wood. It blooms best if pruned in the spring, before new growth starts.