Difference between Hydrangeas and Rhododendrons
By Andrew Parker - June 29, 2023

Hydrangeas and rhododendrons share very many similarities. For one, they are both easy to reproduce by stem cutting and are sensitive to soil pH, making them favor acidic soils. These species are frequently utilized in bulk plantings and upright shrub borders.

Definition

Rhododendron is an extensive genus of roughly 1,024 woody plant species in the heath family (Ericaceae). They may be evergreen or deciduous. Most species are endemic to eastern Asia and the Himalayan area, but one may also find fewer in North America, Europe, and Australia.

Hydrangea is a popular garden plant whose name comes from Greek and means “water vessel.” It is a genus of around 75 species of flowering plants native to Asia and the Americas with several popular names such as hydrangea or hortensia. Eastern Asia, particularly China, Korea, and Japan, has the most species variety. Most are shrubs 1-3 m tall, but some are tiny trees, and others are lianas that may climb up trees to reach 30 m (100 ft). They can be deciduous or evergreen. However, the temperate species that are frequently farmed are all deciduous.

Rhododendrons vs. Hydrangeas

While hydrangeas and rhododendrons love acidic soil, they have different light requirements. Hydrangeas thrive in early sun and afternoon shade, with shelter from winds, but rhododendrons thrive in full sun and even partial shade, though they prefer direct sunshine.

Rhododendron blossoms are sprinkled among the leaves, while hydrangea appears as a mass of fluffy blooms at the ends of the stalks. In full bloom, the hydrangea shrub will seem like a profusion of fluffy colored blooms with few leaves showing. Rhododendron blossoms will be dispersed throughout the leaves.

Hydrangea leaves are less dark green than rhododendron leaves, which can be quite dark green. They also require a lot more watering than hydrangeas

Comparison Chart
RHODODENDRONSHYDRANGEAS
  1. The flowering period is brief
Flowers throughout summer
  1. Dark green leaves and flowers scattered among the leaves
Flowers appear at the tip of stalks