Fragrant Hydrangeas

Summer is incomplete without Hydrangeas everywhere! Hydrangeas are native to the warm temperate and subtropical forests of East Asia and the United States, and there are many wild varieties. Garden hydrangeas are normally grown for colorful, big, bushy blooms, particularly seen in H. macrophylla. Who doesn’t love the big bushy blue to pink and all colors in between blooms? Your nose. That’s right! Those Hydrangeas you  normally love are not the fragrant ones in most cases.

What’s in a name?
Call them what you will–mophead, French, bigleaf, florist, garden, lacecap, hortensia–they’re all Hydrangea macrophylla. Speaking of names, “Hydrangea” stems from two Greek roots, ‘hydro’ meaning water and ‘angeion’ meaning vessel. Together, the rough translation is “water vessel,” which refers to Hydrangeas’ thirst for water.

The more colorful Hydrangeas are the Asian varieties, but in a horticultural world twist- the fragrant ones are the American varieties! Normally its the other way around (viburnum and osmanthus come to mind here) but the mold must always break somewhere. The American genus leading the way on fragrance is oakleaf hydrangea, H. quercifolia.The similar H. radiata and H. cinerea are also similarly fragrant.

Oakleaf hydrangeas are native to the Southeast, and grow in the Piedmont and coastal plains. Oakleaf hydrangeas are not modest plants, one specimen at the University of Kentucky arboretum was eight feet high with a ten foot spread, and that still isn’t the largest out there! They grow to be nearly thirty feet in the wild, and have a large open crown. In the wild, they often form large thickets, as the plant spreads via underground stems (stolons) and have identifiably cinnamon-brown, peeling bark. The large five-lobed leaves look similar to oaks (hence the oak leaf) but much larger- up to eight inches in length, and turn a brilliant red in fall. In summer (May-September), these Hydrangeas bloom with an odd spiked display- flowers are small ‘spiky balls’ in between petaled bracts that appear as the ‘flowers.’ The whole spike is nearly a foot long, and ages from white to pink to brown, where they will hang on all winter as the lower leaves drop off.

The scent is very interesting in these plants. Its brought out best by heat and humidity. Anyways, its a smell that is sour but extremely sweet, bordering on overkill, and cloys quickly en masse. Its not indolent like others, but cloying like privets are. I love them, but its not a scent I want in my garden come evening if that makes sense.
​
These plants are great in a forest garden or under planting for trees, and there are many cultivars (including dwarfs) available. I would avoid hot sun as these plants cannot handle drought and must be well watered and kept from wilting. Lastly, they are hardy in zones 6-9, and marginally hardy in zone 5.

H. radiata and H. cinerea are also native to the Southeast, but H. radiata is limited to the Southern Appalachians and H. cinerea spreads to the Ozarks. H. radiata is called the silverleaf hydrangea for its leaves being silvery on the undersides, and H. cinerea is called the grey hydrangea likewise for its grey pubescent leaf underside. The two both grow to be ten feet tall and have flowers in corymbs, blooming in June to July. Both plants can be cultivated in gardens, but silverleaf hydrangea is the more difficult of the two, as it requires cooler temperatures and more moisture than grey hydrangea, although it is showier

Only a few are fragrant
Some say they find Hydrangea fragrant, others, not so much. Below are the fragrant species and cultivated varieties of Hydrangea

Hydrangea quercifolia: the smell is a rich honey-vanilla. This shrub is also a wonderful magnet for honeybees, bumblebees, pollen wasps, and syrphid flies. Its inner flowers are fertile, while the more dramatic outer sepals are sterile. 

Hydrangea angustipetala with Golden Crane® Hydrangea (Hydrangea angustipetala ‘MonLongShou’) there is no debate. This rare and precocious shrub only blooms in late spring – among the earliest of all Hydrangeas to bloom – but is sweetly scented, a trait very rare in this genus said to smell strongly like jasmine or sweet alyssum. The jasmine-like scent will perfume an entire garden! 

Hydrangea scandens: The lacy cream-colored flowers pack a powerful fragrance during March and April. Hydrangea scandens ‘Fragrant Splash’ adds a bonus of variegated foliage.

Hydrangea macrophylla ‘Ayesha’: “one of the only Hydrangeas to have a delicate fragrance in bloom”

Hydrangea paniculata: “slight floral scent” or “mild fruity fragrance”

When to Plant Hydrangeas by Type
"When planting hydrangeas, time is of the essence, like with most plants. But you do have a pretty large window to play with. The key is to find a period when you don't risk frost and to avoid drought at the same time," says Amber Noyes, horticulture and gardening expert and executive editor of Gardening Chores.

Here are the common types of hydrangeas and when to plant them according to the experts.

Hydrangea Shrubs: Fall and spring are the best times to plant hydrangeas shrubs. You can technically also plant them in the summer, but it is not recommended. She says if you do, you must ensure that you keep watering the shrubs and avoid full sun because heat can stunt their efforts to set roots in the new soil. "Transplant your hydrangea when it is dormant, and absolutely avoid it when the plant is in bloom. At this stage, it is at its weakest, and the least you can expect is that all the large blossoms wilt away, but foliage and growth will suffer as well," she explains. Jen McDonald, certified organic gardener and co-founder of Garden Girls, says where you plant is also vital. "Because there are so many different varieties of hydrangeas, it's important to select the variety based on where you'd like to plant it. Oakleaf hydrangeas require shade to thrive. Bigleaf hydrangeas love some sunshine. Choose a location that favors the hydrangea you select," she advises.

Hydrangea Quercifolia: The oakleaf hydrangea is one of the most beautiful shrubs you can grow in the garden. It is not as popular as some other plants mentioned on this list but it is a great choice for those who want to have a garden full of fragrance. The flowers of this shrub resemble those of the common Hydrangea paniculata but are much larger. Flowers grow from huge conical heads in June. They are white when they first open but as the season advances they get a rosy hue. At the maturity, the flowers have a purplish tint. This is such a wonderful shrub even when it doesn't flower. It has very beautiful foliage. It is shaped like oak leaves. The leaves change color during the season, turning into bronze. In order to make this plant thrive, it is best to grow it in shade or in full surf

Climbing Hydrangea
Should you plant climbing and shrub hydrangeas at different times? Noyes says the answer is no; the same timing applies to both types. Fall is typically the best time to plant, with spring being a close second. Planting in fall is often preferred because the hydrangea is approaching or already in its dormant phase and is therefore not using much energy. It is in the process of transitioning energy from the foliage back into its roots, minimizing the potential for damage. There is a narrower window with spring planting, and it does come with potential risks. At this time, the hydrangea is initiating new buds and shoots growth, transferring energy from the roots to the leaves. If the leaves have already started to open, the plant may suffer from transplant shock, potentially preventing flowering for that year or resulting in a weak bloom. if you opt for spring planting, make sure that it is at the latest when you see tiny new buds growing on the branches and never past the first few leaves that have fully opened.

Potted Hydrangea
"When it comes to planting hydrangeas in pots, however, the opposite is true. It is better to do it in spring, and fall comes as a second choice, but not as close. The point is that plants in pots are not as sheltered from frost as they are in the ground, and you don't want to take a risk," Noyes says. She advises taking some precautions if there is a chance of frost, such as wrapping up your container with something warm, like straw, for example. "However, in warmer climates, transplanting them in fall is quite feasible and usually successful."

Potted Hydrangea to In-Ground
If you are wondering when to plant hydrangeas from a pot into the ground, Tammy Sons, horticulturist and CEO of TN Nursery, always suggests transplanting them in the fall. "The best time to transplant hydrangeas is in fall or early spring. Fall is the best time to plant anything because dormancy is approaching, and any kind of transplanting shock or stress the plant will have all winter to adapt and harden off before it starts its growth the following spring," she explains.

Some Fun Facts About Hydrangea
As you would expect anything this magical must have special meaning, right. No surprise, it’s the fourth anniversary flower.

Blue to pink, pink to blue, but…
No matter how much you try to change the soil pH, white flowering varieties will always stay white