If you are looking for a reliable ornamental plant that has a lot to offer, then you should consider including hydrangeas in your garden. You can use them as shrub borders, in a mixed planting with other perennial flowering plants, or planted individually in pots or containers.
Hydrangeas are one of the showiest flowering plants that are readily available worldwide. A gardener’s favorite for decades, these shrubs produce colorful flowers that bloom in the summer and fall.
- Hydrangea Facts
- What Are The Popular Hydrangeas Species and Cultivars?
- Bigleaf or French Hydrangea (Hydrangea macrophylla) Cultivars
- Smooth Hydrangea (Hydrangea arborescens) Cultivars
- Panicle Hydrangea (Hydrangea paniculata) Cultivars
- Oakleaf Hydrangea (Hydrangea quercifolia) Cultivars
- How To Grow Hydrangeas
- Meaning and Symbolism
Hydrangeas or scientifically referred to as Hydrangea spp. is an extensive genus of erect or climbing woody flowering shrubs under the Hydrangeaceae botanical family. They originated from Eastern and Southern Asia and portions of the Western Hemisphere.
The genus has nearly 75 species of shrubs or small trees. Among these are six recognized species, including Hydrangea arborescens (smooth or wild hydrangea), Hydrangea cinerea (ashy hydrangea), Hydrangea macrophylla (bigleaf or French hydrangea), Hydrangea paniculata (panicled hydrangea), Hydrangea quercifolia (oakleaf hydrangea), and Hydrangea radiata (silver leaf hydrangea) (1).
Hydrangea flowers traditionally come in white, but more color options such as pink, blue, purple, and red are available today.
Interestingly, the colors of hydrangea blooms are influenced by the presence of aluminum ions in the soil. The flower color changes depending on the soil pH level where they are planted since hydrangeas are one of the few flowering perennial plants that accumulate aluminum.
Soil conditions that are more acidic with lower soil pH (ideally 4 to 5) would result in blue blooms since aluminum is present, while a more alkaline soil (soil pH of 6 to 7) would give pink flowers.
Plant Name and Origin
The genus name Hydrangea originates from the Greek words hydro and angeion, meaning “water” and “vessel,” respectively. Although the name refers to the shape of the plant’s seed pods, it couldn’t be more fitting since hydrangeas require lots of water.
Hydrangea plants should never be allowed to dry out. Hence soil condition must be kept moist most at all times (2).
Another known common name of hydrangea is hortensia.
Hydrangeas are one of the most versatile garden plants such that they can play various roles in any garden. They suit well in borders, mixed with flowering perennial plants, or even planted in pots and containers.
When using hydrangeas as shrub borders, it is best to plant them with boxwood or other evergreens since they lose their leaves in the fall.
Hydrangeas are deciduous woody shrubs, climbers, or small trees that range in size from 4 to 12 feet tall, depending on the variety. The blooms vary in color, which can be white, lime green, purple, blue, or pink (3). Generally, the hydrangeas’ growth rate is relatively fast.
Flowering typically commences from early spring and lasts until late autumn. Individual flowers are small but appear in prominent clusters at the ends of the stems. A modified bract surrounds each flower.
Hydrangea flower clusters are of three types: mophead, panicle, and lacecap. The mophead flower clusters are globe-shaped. Flower clusters that are long and resemble cone shape is a panicle type, while those that are flat type are a lacecap (4).
What Are The Popular Hydrangeas Species and Cultivars?
Bigleaf or French Hydrangea (Hydrangea macrophylla) Cultivars
Hydrangea macrophylla is commonly known as the bigleaf hydrangea or French hydrangea. It is also called Japanese hydrangea or snowball hydrangea.
These hydrangeas are famed both in gardens and floral shops as a gift plant, especially for Mother’s Day. They are also popular as this is the kind of hydrangeas with flower colors that can be modified from pink to blue or vice versa by adjusting the soil pH (5).
‘Nikko Blue’ Hydrangea
One of the most popular hydrangea cultivars, the ‘Nikko Blue’ hydrangeas gains recognition for its showy, large, rounded mophead flower clusters that are densely packed with deep blue florets.
‘All Summer Beauty’ Hydrangea
While most hydrangeas flower for only a month or so, the ‘All Summer Beauty’ cultivar makes a difference. This hydrangea produces attractive blooms throughout the entire summer. It grows up to 3 to 4 feet upon full maturity.
The floriferous ‘All Summer Beauty’ hydrangeas have a mophead type of flower clusters in pink or blue. This cultivar bloom on both old and new wood.
‘Forever Pink’ Hydrangea
The ‘Forever Pink’ cultivar produces attractive mophead clusters of hot pink with red overtones florets. It reaches about 2.5 to 3 feet in height.
‘Red Star’ Hydrangea
This bigleaf hydrangea features lacecap clusters of red to purple-red flowers in alkaline soils. Mature plants reach about 3 to 5 feet both in height and spread.
Other popular cultivars of bigleaf or French hydrangeas are the following: ‘Variegata’, ‘Pia’, ‘Tovelit’, ‘Glowing Embers’, ‘Endless Summer’, ‘Endless Summer Bloomstruck’, ‘Blushing Bride’, and ‘Twist and Shout’ (4).
Smooth Hydrangea (Hydrangea arborescens) Cultivars
Hydrangea arborescens or smooth hydrangeas are also referred to as sevenbark or wild hydrangea. These hydrangeas are small to medium-sized, which grow about 3 to 5 feet in height and spread upon full maturity.
They are known for their long-lasting, large, rounded white flowers that bloom on the current season’s growth. The first blooms show a light green color but turn to cream or bright white as the flowers mature.
The ‘Annabelle’ cultivar of smooth hydrangeas is a classic favorite among many gardeners and flower enthusiasts. This deciduous shrub blooms for up to two months and showcases massive, rounded flower clusters that are 10 to 14 inches wide (4).
‘Snow Hill’ Hydrangea
The Hydrangea arborescens ‘Snow Hill’ is similar to the famed ‘Annabelle’ cultivar, only with smaller flower clusters (4) that grow up to 8 inches wide. The plant reaches about 6 to 8 feet tall upon full maturity.
It is also called as hills-of-snow hydrangea.
Panicle Hydrangea (Hydrangea paniculata) Cultivars
Hydrangea paniculata or panicle hydrangeas are native to eastern China and Japan (4). These hydrangeas are vigorous, upright, and fast-growing. Generally, mature plants reach about 8 to 15 feet tall and spread about 6 to 12 feet. Fascinating white blooms are the recognizing feature of this kind.
The ‘Grandiflora’ hydrangea is also called as the PeeGee hydrangea or PG hydrangea. Mature plants reach about 10 to 25 feet in height and spread up to 16 feet. The blooms appear in white but slowly age to pink then fade to brown. The flower clusters are conical, typically 6 to 8 inches across.
‘Grandiflora Compacta’ Hydrangea
The ‘Grandiflora Compacta’ cultivar is the compact version of the famous ‘Grandiflora’ hydrangeas. Mature plants reach about 4 to 6 feet in height and width, with white or cream flowers that slowly fade to pink as they mature.
This panicle hydrangea cultivar grows up to 8 feet upon maturity. It is native to China and Japan. The ‘Limelight’ hydrangeas have cone-shaped panicles of creamy white flowers that mature to chartreuse-lime then pink and eventually fade to beige.
Other cultivars of panicle hydrangeas include ‘Pink Diamond’, ‘Tardiva’, ‘Unique’, and ‘White Moth’.
Oakleaf Hydrangea (Hydrangea quercifolia) Cultivars
Hydrangea quercifolia, or otherwise referred to as the oakleaf hydrangea or oak-leaved hydrangea, is native to the southeastern part of the United States. This kind of hydrangea typically grows about 4 to 6 feet tall and blooms on old wood (4).
Harsh winter conditions could make Oakleaf hydrangeas lose substantial amounts of flower buds or die to the ground.
‘Snow Queen’ Hydrangea
The ‘Snow Queen’ hydrangeas showcase stunning blooms of large and upright conical flower heads with white florets, as well as lobed, oak-like leaves that turn bronze-purple to red in the fall. Mature plants reach up to 6 feet tall and spread up to 8 feet.
The ‘Snowflake’ oakleaf hydrangea features double-flowered blooms with cone-shaped white flower clusters that turn rosy-pink as they mature. The oak-like leaves turn bronze-purple to red in the fall. Mature ‘Snowflake’ hydrangeas grow about 6 to 10 feet in height and spread.
Other recognized oakleaf hydrangea cultivars include ‘Alice’, ‘Pee Wee’, and ‘Sike’s Dwarf’ (4).
How To Grow Hydrangeas
Culture, Care, and Maintenance
Regardless of the variety, hydrangeas should be planted in well-drained, moist, and fertile soil as these plants do not thrive well in drought. Each plant requires six to eight hours of full sun exposure to make the blooms happy, vibrant, and abundant. They are shade tolerant, but too much exposure to heavy shades would result in lesser or no flowering (3).
One of the known characteristics of hydrangeas is that these plants love water. Optimum performance can be achieved if the plants are given adequate water supply, especially during hot and dry weather conditions (3). Generally, hydrangeas require an inch of deep-soaked water per week then two inches per week when the weather’s hot and dry to keep them from wilting (6).
If allowed to dry out, hydrangeas may produce lesser flowers the following season or not fully recover at all. Avoid watering the leaves as much as possible to minimize diseases such as leaf spot disease (3).
As discussed above, the colors of some hydrangea varieties may change depending on the soil pH. Hence, gardeners can modify the soil condition by introducing aluminum sulfate or sulfur to reduce the soil pH.
However, hydrangeas may develop an iron deficiency if the soil PH is too high. In such cases, the plants would exhibit yellowing in younger leaves (3).
Why won’t my hydrangea flower?
This is a common question people often ask when it comes to growing hydrangea. Failure to flower is a common cultivation problem encountered by many. Several factors may affect this issue. But usually, it is a result of a winter injury to the flower buds or too much exposure to dense shade. Improper pruning, likewise, can lead to flowering failure.
Pests and Diseases
Hydrangeas are susceptible to several fungal diseases, including but not limited to powdery mildew, Cercospora leaf spot, and anthracnose (7). Such conditions can be prevented by removing any fallen leaf. Also advised is the use of drip irrigation or soaker hoses for watering the plants. The use of pesticides is another option.
Other plant diseases that can affect these plants are Botrytis blight, root rot, blister rust, and bacterial wilt (8).
Likewise, insect pests like aphids, black vine weevil, four-lined plant bug, Hydrangea leaf tiers, Japanese beetles, Rose chafers, and two-spotted spider mites can infest hydrangea plants and cause damages.
Growing hydrangeas could come with a price. Although not as toxic as other poisonous plants, hydrangeas could result in diarrhea, vomiting, abdominal pains, or gastroenteritis in humans or animals when ingested in large amounts.
The flower buds and leaves of these plants, in particular, contain glycoside amygdalin. This chemical compound breaks down to produce cyanide once metabolized. Exposure to hydrangeas could also cause dermatitis or skin irritation in sensitive individuals (9).
Meaning and Symbolism
Generally, hydrangeas are a known symbol of persevering love, gratefulness, honesty, and vanity. However, because of an extensive selection of these flowering perennials, different hydrangea flower colors bear different meanings.
Pink hydrangeas are said to express love and sincere emotions, mainly because they resemble hearts with their shape and color.
Blue ones, on the other hand, symbolize regret, frigidity, and forgiveness.
Like other white flowers, white hydrangeas mean purity, grace, and abundance. Different meanings note boasting or bragging.
Purple hydrangeas are also a symbol of abundance, as well as wealth and royalty. These plants also represent a desire to understand another individual deeply.
Moreover, hydrangeas are recognized as a symbol of appreciation. These fascinating blooms are often given as a fourth wedding anniversary gift.
Did you find this hydrangea beginner’s guide useful and informative? Check out our article on perennial plants and flowers for more information about flowers similar to hydrangeas.
(1) Plants.usda.gov. (2019). Classification | USDA PLANTS. [online] Available at: https://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=HYDRA&display=31
(2) Ipm.missouri.edu. (2018). Hydrangea: The chameleon of plants (David Trinklein). [online] Available at: https://ipm.missouri.edu/MEG/2018/3/hydrangea/
(3) Ladybug.uconn.edu. (2019). Hydrangea. [online] Available at: http://www.ladybug.uconn.edu/FactSheets/hydrangea.php
(4) Perry, L. (2019). Hydrangeas. [online] Pss.uvm.edu. Available at: https://pss.uvm.edu/ppp/articles/hydrangeas.html
(5) Extension.uga.edu. (2017). Growing Bigleaf Hydrangea | UGA Cooperative Extension. [online] Available at: https://extension.uga.edu/publications/detail.html?number=C973
(6) Center for Agriculture, Food and the Environment. (2015). Growing Hydrangeas. [online] Available at: https://ag.umass.edu/landscape/fact-sheets/growing-hydrangeas
(7) Kluepfel, M. and Williamson, J. (2004). Hydrangea. [online] Home & Garden Information Center | Clemson University, South Carolina. Available at: https://hgic.clemson.edu/factsheet/hydrangea/
(8) Ladybug.uconn.edu. (2019). Hydrangea: Diseases and Pests. [online] Available at: http://www.ladybug.uconn.edu/FactSheets/hydrangea-diseasesand-pests.php
(9) Cbif.gc.ca. (2013). Canadian Poisonous Plants Information System – Hydrangea (Common name) – Canadian Biodiversity Information Facility (CBIF). [online] Available at: https://www.cbif.gc.ca/eng/species-bank/canadian-poisonous-plants-information-system/all-plants-common-name/hydrangea/?id=1370403267136
*Photos credit: Couleur, MrGajowy3, thvldml1004, ustm66, JACLOU-DL, Walter46- Pixabay