In this article, we will be discussing white-blooming hydrangeas. Three genii of white hydrangeas are the most popular: H. paniculata, an introduced hydrangea from the Far East; H. arborescent, native to the Piedmont and mountains; and H. quercifolia, which is native throughout the Southeast.
H. paniculata was a very popular hydrangea in the last century. It is tall-growing and is best used in full sun. “Peegee” hydrangea is a variety that became popular in the ’40s, and it was used extensively.
It can still be found in historical settings, particularly in the mountains. In the ’70s, tardive hydrangea became the most popular variety of this genus. It has a large, elongated bloom.
New Varieties Of White Hydrangeas
These varieties have now fallen out of favor with most gardeners, primarily due to their large size and the improvements made to other cultivars.
The most popular H. paniculata today is limelight hydrangea. This plant has big, beautiful blooms in mid-summer. It blooms on new growth, which means it can be pruned in the spring before May 1. The limelight grows bigger than most folks realize and can quickly grow to 8 feet tall.
Because many gardeners today can’t use a plant that grows that tall, growers have developed a smaller version. “Little Lime” hydrangea grows about 4 feet tall and wide and has proven helpful in today’s gardens.
H. arborescens is also referred to as smooth hydrangea or mountain hydrangea. These hydrangeas can be found growing wild along roadsides and trails in northern Greenville County and also along the Blue Ridge Parkway. They are a real treat to encounter while hiking and touring.
The most popular smooth hydrangea is the variety “Annabelle.” An improved variety is named “Incrediball.” This hydrangea has beautiful white flowers that can grow 12 inches tall and wide. H. arborescens varieties grow about 6 feet tall and do well in full sun settings.
H. arborescens also blooms on new growth. Gardeners in more northern climes cut these plants to the ground and let them emerge anew every spring. This produces a beautiful show of blooms in mid-summer.
H, quercifolia is oak leaf hydrangea. This beautiful plant is native to every state in the Southeast. In South Carolina, it is found in the wild below Columbia. It is found in every county in Alabama and is the Alabama state flower.
Oak Leaf Hydrangea
Oak leaf white hydrangea tolerates full sun but does best with afternoon shade. It has long blooms in mid-summer that are about 8 inches long. The fall color is a gorgeous burgundy, and the cinnamon-colored exfoliating bark is a delight in the winter.
Oak leaf hydrangea blooms on old wood, so it is best to prune right after it blooms, allowing for new growth in late summer. Next year’s blooms will be found in that late-summer growth.
Oak leaf hydrangea grows 6 to 8 feet tall. “Pee Wee” is a dwarf variety of oak leaf hydrangea that grows about 4 feet tall.
It’s hard to go wrong using these white-blooming hydrangeas. Because they are deciduous, they are not really recommended for foundation plantings. Further out in the landscape, they are excellent to use for borders or as individual specimens.
The Best Use Of Hydrangeas
As with all deciduous plants, use white hydrangeas before evergreen plants. When these plants lose their leaves, the eye of the viewer is drawn to the background plants.
Don’t pooh-pooh plants that go dormant. Many of those plants that look like “a bunch of sticks” in the winter provide the most interesting looks in the summer.
Peaks and valleys, change and variety, and differing looks in different seasons create exciting features in the landscape. Deciduous plants attain this goal more than any other plants.
Another feature that hydrangeas have is that they are easy to root. In the middle of the summer, after the new growth has hardened off, cut off a 6-inch length of the stem. Strip off all but a single terminal leaf and apply a rooting hormone.
Put this cutting in a well-drained potting mix with lots of perlite. Mist the single leaf several times daily to keep it from drying out. Keep the potting medium dry. You may have roots in 10 days, but definitely within three weeks.
Hydrangeas are excellent for cutting propagating, so here are a few pointers to get you started. Softwood cuttings taken in early spring, when the plant has begun to grow, are ideal – you want new, soft, new growth.
It is preferable to do this very early in the morning, while the plant is still full of water, and immediately place them in a plastic bag. The essential thing to avoid is the cutting drying out; once this happens, it will not be successful, so try to get it potted up as soon as possible.
Strip the leaves save for the top leaves and cut right below a leaf node, where there is a high concentration of growth hormone. Again, this will assist the cutting in retaining moisture, as most water is lost through its leaves.
Dip cuttings in hormone powder and gel before placing them in cuttings compost. Water the compost and keep it from drying out.
A propagator unit with a heated bottom of 21 degrees Celsius will accelerate root development. Still, you may also wrap the cuttings in a plastic bag and place them somewhere warm but not in direct sunshine. It should have successfully rooted in about 10 weeks.
Hydrangeas are mostly low-maintenance plants, but brown stains on the foliage can occur. It’s a leaf-spot disease caused by a bacterial or fungal infection.
It can occur in high humidity when the air is warm and damp, and there is minimal airflow. If you catch it early and it only affects a few bottom leaves, you can remove them, sometimes preventing the spread.
Otherwise, exercise caution when watering. Direct the hose at the plant’s base and avoid watering overhead.
The hydrangea scale insect is another prevalent issue. This is most likely the culprit if you notice white, fluffy gunk on your plant’s stems.
The adult deposits its eggs on the stems and covers them in this white, waxy substance to protect them. Even if the eggs hatch in the summer, the waxy substance remains.
The sap from your plant is then sucked by these insects, weakening the flowers and leaves.
If the infestation is severe, you may need to remove the plant. Still, you can try to control it by cleaning it with a soapy solution next spring and summer to remove fresh eggs and spraying with a pesticide or organic pest control during July when the eggs hatch, paying particular attention to the undersides of the leaves.
One of the most popular questions I get is about how to prune hydrangeas. Keep the blossoms on over the winter to protect the flower buds from frost. It may appear a little sloppy, but it’s worth the wait.
Then, in the spring, trim back to a couple of healthy buds, and as your plant grows, perhaps some rejuvenation pruning can assist – entirely remove around one-third of all stems back to the ground and remove any dead or diseased growth.
How to change the color of hydrangea flowers naturally.
Hydrangeas are available in various colors, from beautiful baby pink blossoms to powder blue petals. On the other hand, some types can change the color of their blossoms over time.
How do you make your hydrangea a different color?
Hydrangeas enliven gardens from April to October, with flowers flowering from April to October.
Mophead and lacecap hydrangeas are the most well-known of these hardy shrubs, with enormous, spherical blooms in white, blue, and pink throughout the summer and early autumn.
These hydrangea cultivars can also change the color of their flowers according to their growing and maintenance conditions.
This is primarily due to the soil they are cultivated and the type of water your plant receives.
There is, however, one exception to the color-changing rule.
White hydrangeas are not affected by soil type. However, they may flush pink in the sun.
The type of soil your hydrangea is growing in affects not just its health but also the leaves it produces and the color of its flowers.
Some hydrangea cultivars are blue or purple when planted in acidic soil and pink or red when grown in alkaline soil.
So, if you plant a magnificent blue lacecap or mophead hydrangea in your garden with neutral to acidic soil, it will produce blue flowers yearly.
The following year, if you put it in alkaline soil, it will flower purple-red or pink, whether it was clear blue or pink when you got it.
Maintaining the color of a plant grown in a pot is more manageable than maintaining the color planted in the ground since gardeners have more control over the soil conditions.
Use compost prepared specifically for “lime-hating” plants to maintain your hydrangea blue.
Feeding lacecap, mophead hydrangeas, and Hydrangea Serrata with a fertilizer low in phosphorus and high in potassium can change the color of the flowers from pink to blue.
To maintain the blossoms blue, cultivate your plant in a pot of peat-free ericaceous compost and irrigate with rainfall. It’s more challenging to change hydrangea flowers from blue to pink. You’ll need to add dolomitic lime to boost the pH.
It is usual for a plant to produce various colored flowers on the same plant during its first year of growth.