What Is A Tree Hydrangea?
A tree hydrangea (Hydnæreza) is a type of flowering shrub or small tree with upright branches. They are native to tropical regions of South America and Africa. They have large, oval leaves which grow from the top of the stem, often reaching up to the branch tips. The flowers are white or pinkish-red and appear in clusters at the base of each leafy branch.
Tree hydrangeas are commonly known as “water lilies” because they produce a water-filled pod that contains a single seed. These pods contain seeds that germinate within two weeks after being exposed to light. The fruit develops into a small, round, green nut about the size of your thumb. If you eat the fruit raw it tastes like almonds but much sweeter and more flavorful.
The name “hydrangea” comes from the Greek word hydros meaning water and rangea meaning flower.
How To Grow A Tree Hydrangea
Growing a tree hydrangea is easy. You just need to provide the proper conditions for its growth. Hydrangeas do not require heavy watering, fertilizing, or even shade; however, they will thrive best if given these things during their first year of life. Once established, you can allow them to dry out completely before adding any additional care.
Tree hydrangeas grow best in well-draining soil that is rich in humus. It should be kept moist throughout the first year of growth before dying back naturally during winter dormancy. They prefer partial shade to full sunlight but can exist in either situation as long as they are given protection from powerful summer sun.
Most varieties are hardy in zones 6 through 9 and can reach up to thirty feet in height.
Strawberry Tree Hydrangea
The strawberry tree hydrangea (Hydnæreza chiapensis) is native to Chiapas and Oaxaca in southern Mexico. The shrub grows up to twenty feet tall and produces clusters of pink or white flowers that bloom during summer. Its leaves turn a bright red in the fall before falling to the ground. The fruit has been eaten by Native Americans for thousands of years and tastes like a sweet, crunchy almond.
Hardy to zones 7 through 9, this tree hydrangea is great for growing in large containers and can easily be trained to cover an arbor or pergola. They prefer full sun to partial shade and should be planted within well-draining soil.
Strawberry tree hydrangeas are easy to find at most garden centers and nurseries. They typically range in price from $15 to $30 each.
Tree Hydrangea Care
Tree hydrangeas are easy to care for and don’t require much pruning unless you want to shape them into specific forms. You should begin by removing any damaged or rotting branches. Then, look to see if the shrub has a vase shape or narrow base; prune accordingly so that the center of the plant is open enough to see through.
After shaping, remove any branches that grow toward the ground. These will often rot and invite fungus and insects to the plant’s center.
While not necessary, pruning your tree hydrangea back in early spring will give it a head start on the growing season.
Tree hydrangeas should be fertilized in early spring either by using a slow-release fertilizer or an organic blend. Follow the instructions provided by the manufacturer.
Tree hydrangeas should be watered just enough to keep the soil from drying out. Drought is the most common reason for leaf and flower drop. The best way to tell if a plant needs watering is to stick your finger into the soil up to your second knuckle. If it feels dry then you should water it.
If it feels damp then you have waited too long.
Fertilize in spring and water when soil feels dry to the touch. Prune as needed. Other than these few easy steps, tree hydrangeas will thrive on their own.
Tree hydrangeas are susceptible to several fungal diseases, including powdery mildew and petal blight. These will typically show up as small, white or grayish spots on the leaves that eventually turn brown and papery. If left untreated, the entire leaf will die and fall off.
Powdery mildew and petal blight are typically caused by poor air circulation or excessive moisture around the plant. If these are severe problems in your area, try cutting holes in the bottom of a bucket. Place the potted hydrangea inside it and only allow the foliage to show above the rim of the bucket. This will prevent moisture from building up around the base of the plant.
Leaves with small holes chewed in them are a sign of a caterpillar infestation. Typically, these pests are brought on the wind from nearby trees or planted as trap crops (i.e. grapes).
If you have the room, consider replacing your tree hydrangea with a thorny bush which will act as a natural barrier to hungry critters.
Crinkled leaves are a sign of overwatering and typically show up when plants begin to go into their dormant phase. Before pruning, always be sure to allow shrubs to transition out of this stage before trimming them back.
As mentioned, tree hydrangeas do not require excessive pruning unless you are looking to change its shape. If you want to keep it small enough to fit in a container, prune away! If you decide to let it grow, feel free to shape it as you see fit.
Deadheading isn’t necessary with tree hydrangeas but can be done if you want the plants to keep their beautiful white color a bit longer.
With extra time and effort, tree hydrangeas can be cut back hard every couple years in order to force them to bloom again. Typically this is done in early spring just before new growth begins. After cutting them back, cover the cut stumps with burlap to keep the sun from bleaching the wood. This should be done in an area that allows for easy transport of the heavy branches to a convenient location for resale.
– Tree hydrangeas are native to China though they are popular throughout Japan and Korea as landscape shrubs.
– There are over 300 known species of tree hydrangeas.
– In the late 1700s, tree hydrangeas were brought over to the United States by gardeners working for the Dutch.
– Tree hydrangeas are incredibly hardy and can survive temperatures as low as -20 degrees Fahrenheit.
– Each bloom on a tree hydrangea means that there is a new root growing below it.
– During the fall of Tokyo, during World War II, citizens planted tree hydrangeas throughout the rubble in order to prevent erosion from winter snowfall.
Sources & references used in this article:
THE HORTENSIAS HYDRANGEA MACROPHYLLA DC. AND HYDRANGEA SERRATA DC. by EH Wilson – Journal of the Arnold Arboretum, 1923 – JSTOR
Genome size variation and species relationships in the genus Hydrangea by M Cerbah, E Mortreau, S Brown… – Theoretical and Applied …, 2001 – Springer
Differences in the allocation patterns between liana and shrub Hydrangea species by Y Kaneko, K Homma – Plant Species Biology, 2006 – Wiley Online Library
Hydrangea paniculata by N Lancaster, W Wesley – 2008 – rhs.org.uk
Sensitivity of Hydrangea paniculata Plants to Residual Herbicides in Recycled Irrigation Varies with Plant Growth Stage by S Poudyal, JS Owen, RT Fernandez, B Cregg – Water, 2020 – mdpi.com
Hydrangea production by M Halcomb, R Sandra – United States: University of …, 2010 – extension.tennessee.edu
Karyotype analysis and physical mapping of 45S rRNA genes in Hydrangea species by fluorescence in situ hybridization by K Van Laere, J Van Huylenbroeck… – Plant …, 2008 – Wiley Online Library
Host infestation patterns of the massive liana Hydrangea serratifolia (Hydrangeaceae) in a Chilean temperate rainforest by RJ Eaton – Rhodora, 1929 – JSTOR