A stray shower or thunderstorm is possible early. Partly cloudy skies early will give way to cloudy skies late. Low 71F. Winds light and variable..

A stray shower or thunderstorm is possible early. Partly cloudy skies early will give way to cloudy skies late. Low 71F. Winds light and variable.

This summer’s hydrangeas have been awesome. The traditional mop head blossoms have lost their brilliant blue color, fading to lime green or baby blue. The panicle and smooth hydrangeas are in full bloom, filling our landscapes with exquisite white flowers in various shapes and sizes. The oakleaf hydrangea blooms are now sporting a tinge of pink, as they were at their peak just a few weeks ago.

Our unpredictable spring 2022 temperatures had threatened our beloved blue mop head hydrangeas, which bloom on old wood. Worry, however, was not necessary as these blue (and pink) charmers shined this summer.

Since gardeners have gotten caught up with the idea of using primarily native plants in their landscapes as well as plants with low water needs, I wondered if, perhaps, the french mop heads and the smooth hydrangeas had lost their panache. This has proven to not be the case. Our love affair with all hydrangeas has exploded as new cultivars keep appearing on the market. Scanning pages on social media and online nurseries, it is quite obvious our fascination with the hydrangea has not withered, but flourished.

The increasing number of hydrangea cultivars on the market keeps the plant collector eager to purchase the newest. In his 2021 book, “The Hydrangea Book: The Authoritative Guide,” Dr. Michael Dirr wrote that there have been 60 new cultivars of Hydrangea paniculata since his 2004 book, “Hydrangeas for American Gardens.”

Dr. Dirr’s book reveals all the hydrangea fan needs to know to choose the best performing hydrangea. I was surprised to see that some in my garden who never had a bloom were listed as poor performers. It was not my fault they never bloomed or had only one pitiful flower. This book is a must for those with a love affair with the hydrangea. His opinions of the plant, glowing or negative, make fascinating reading for the novice or the expert.

Although there are many other species of hydrangeas, gardeners often associate hydrangea with Hydrangea macrophylla (french, hortensia or lace cap hydrangea). This deciduous shrub can bloom on old wood, frequently causing it to fall victim to late cold snaps. It is important not to prune this hydrangea after the first of August, or you may remove next year’s blooms. Breeders have come up with re-bloomers that bloom on old and new wood, thus partly escaping the late freezing temperatures. ‘Endless Summer’, ‘Dooley’ and ‘Sister Theresa’ are examples of amazing big leaf hydrangeas. ‘Merritt's Supreme’ is an outstanding pink flowered mop head.

Another popular hydrangea is Hydrangea paniculata, or panicle (cone shaped) hydrangea. Their magnificent panicles of large white flowers are a must in any garden. These dependable bloomers do not seem to be bothered by the cold. They bloom from early July into fall, with flowers taking on a pink tone as they grow older. Panicle hydrangeas bloom on new wood so they can be pruned in late winter. These hydrangeas are more able to stand the sun than the macrophyllas, but they need a steady stream of moisture the more sun they get. ‘Grandiflora’, ‘Pinky Winky’, ‘Quick Fire’ and ‘Lime Light’ are all beautiful specimens. For those seeking a smaller paniculata, ‘Bobo’ is a fantastic addition to the garden. For those who do not have room for a ‘Limelight’, ‘Little Lime’ fits into a smaller space and is just as showy as its bigger relative. My sister grows ‘Tardiva’, an oldie but goodie; when the deer do not eat all the flowers, she describes it as gorgeous.

Hydrangea macrophylla, the most often seen in southern gardens, is perhaps the hallmark of the garden in the summer. Although we may refer to it as the french hydrangea, it is not from France at all. (Not originally. This garden beauty is a native of Asia — Japan, China and other Asian countries.). The macrophylla appeared in Europe before 1899. In “Heirloom Gardening in the South,” William Welch wrote, “The hortensia was available locally by the late nineteenth century. An 1881-82 Langdon Nurseries catalog (near Mobile) lists H. Hortensis (‘an elegant well-known plant’), H. Imperatrice eugenia (‘a new variety’), H. paniculata grandiflora (‘new from Japan’) and H. japonica. H. Paniculata was listed in garden catalogs in 1896.”

The French, however, had begun to breed this lovely extensively around the turn of the twentieth century, producing two types of Hydrangea macrophyllas: hortensias and lace caps. The hortensia have large clusters of eye-catching, mostly sterile flowers, earning the name ‘mop head.’ The French also introduced the lace cap hydrangeas, which have a center of fertile flowers surrounded by a ring of showy sterile flowers. Although the lace caps are quite charming, the mop head seems to garner more attention.

The first hydrangea in the south was not the big leaf hydrangea, but Hydrangea quercifolia, the oakleaf hydrangea, a native of the southeastern United States. William Bartram named the plant and had introduced the oakleaf in English gardens in 1803. (William Welch)

One of the common questions about mop head hydrangeas is “why do they not bloom?”

After reading Dirr’s book, I recognized that my ‘Big Daddy’ — described as bearing basketball flowers — produced less than a handful in twenty years, each one about the size of a small tennis ball. Dirr was correct when he said it was not much of a garden flower. It may find itself in the compost bin later this year. Not all hydrangeas are meant to be stars.

As with all plants, hydrangeas must be planted in the right place for the species of hydrangea. Some need shade. Some thrive in the sun. Know your species and know its needs.

Although hydrangeas are possibly the most popular plant in southern summer gardens, it can be difficult. Some years there is not a single flower. According to the University of Massachusetts Landscape Program, the following can be reasons for the lack of flowers.

• Incorrect pruning is a sure cause of no flowers. Mop heads blooming on old wood should not be pruned in the summer, as we will be cutting off next season’s blooms. The flower buds develop on the limbs during the summer. Pruning should be limited to removing just spent flowers. The types we call re-blooming bloom on new wood and can be carefully pruned in the spring to remove dead branches only. For some mop heads blooming on old wood and new wood, removing the old wood may also remove blooms.

• The right light is important! Bigleaf hydrangeas need some morning sun to bloom well. It will take some afternoon dappled shade or part sun. Too much deep shade will prevent your hydrangea from blooming, as will too much sun. These are not sun lovers.

• Hydrangeas must be watered. They need well-drained soil to thrive, as well as ample moisture. If they are without proper moisture, the stress of drought will reduce the flowers. Be careful; hydrangeas do not like to be over-watered either.

• Too much fertilizer, especially nitrogen, will impact blooming. Too much nitrogen means lots of green leaves and less flowers. Even fertilizer washing from other areas of your yard may impact a mop head, which needs a higher dose of phosphorus. Instead of fertilizer, give your hydrangeas good rich soil full of amendments. There are special fertilizers on the market for hydrangeas; however, use all fertilizers with care and never without a soil test.

• Young plants may not bloom, needing time to mature. Initial root growth and survival are important; flowering will begin as the shrub ages.

Some things that keep our mop heads from blooming are completely out of a gardener’s control. The University of Massachusetts Extension program points to environmental factors for a lack of blooms.

• Winter damage can certainly affect the number of blooms and even the plant’s health. Bigleaf hydrangeas are cold hardy to zone five. But even the ones that can handle the cold can not stand up to sudden spring freezes, which are common in our area.

• Bitter winter temperatures can also damage the buds on a mop head, leaving the plant with no summer flowers.

• A cooler summer may affect the flowering on french hydrangeas.

• All hydrangeas do not fare well in drought. Excessive heat and dry spells may hinder blooming, especially in our french hydrangeas.

Sometimes french hydrangeas will die back to the ground (as often happens in my garden) during exceptionally cold winters, and come up from the root. Normally, I will not see any flowers that year.

Hydrangea quercifolia, or oak leaf hydrangea, is another hydrangea familiar to most Alabamians as it is our state wildflower and native to our area. This deciduous shrub may reach six feet and is wonderful planted in groups. If you choose to prune your oak leaf, do so before July 5; however, this hydrangea normally does not need pruning. The only time I have pruned mine was when it got leggy and all the flowers were over my head. Soil that does not drain well is certain death to an oakleaf hydrangea. The oak leaf hydrangea has wonderful fall color when the leaves take on red, rust and purple colors. This native blooms the brightest in May and June, taking on a pinkish tinge as it ages. Popular oak leaf hydrangeas are ‘Snow Queen’, ‘Snowflake’ and ‘Harmony.’ New in my garden is a ‘Honey’, an oakleaf with chartreuse colored leaves.

Although mop head hydrangeas may live in large containers, the oakleaf prefers the ground. I just bought one I am going to try in a container as I have run out of garden real estate. I have not tried panicle or smooth hydrangeas in containers, but I suspect they may be happier in the soil.

Smooth hydrangeas — Hydrangea arborescens — have become a darling in the world of hydrangeas. These hydrangeas can tolerate almost full sun; they, however, must have adequate moisture to keep them flourishing. These hydrangeas are also natives for those seeking a native hydrangea. Smooth hydrangeas bloom on new wood and benefit from a hard pruning in late winter. ‘Annabelle’ has quite large white blooms in the shape of big balls; however, any water or wind will make them flop to the ground. I have tried many ways to keep them upright, but my sister suggested to me that the best way to keep them upright is to plant them in a row where neighbors help to give them support. Popular cultivars are ‘Annabelle’, ‘Grandiflora’, ‘Hayes Starburst’, ‘Incrediball’ and ‘Invincibelle Spirit’.

For those seeking a hydrangea that climbs, look no further than Hydrangea anomala petiolaris. It can get really long, reaching 40 to 60 feet. They are slow to get started, but once they get going, watch out. I had one that wanted to spread out to the ground around it, and proved to be a bit aggressive for my garden.

As for pruning, each species of hydrangeas has a different requirement. That information is vital to the gardener and can be easily located on ACES.edu. Removing dead, damaged or crossing branches carefully is necessary on any hydrangea any time of the year.

All hydrangeas need good well-drained, amended soil, and moisture. They are not a fan of heavy clay soil. Mulching hydrangeas is important to their overall health and well being.

When watering hydrangeas, take care to water the roots instead of the leaves to keep them from developing viruses or diseases.

Although the other species of hydrangea may develop some disease, problems are most prevalent in french hydrangeas. Mop head hydrangeas are prone to powdery mildew, leaf spot and bacterial wilt. It is important for plants with leaf spot to remove all these diseased leaves from the plant and the ground underneath it to prevent spread. I prefer cleanliness over chemicals.

Many gardeners never seem happy with the color of the flowers on their mop heads; thus they spend time and effort trying change them. My opinion is to enjoy what you have. Blue flowers prefer acidic soil (pH of 5.0 to 5.5). Hydrangeas with pink flowers prefer alkaline soil. To change the colors, the gardener has to change the pH of soil. Accept your soil and your hydrangea.

With loving care and knowledge, our gardens can overflow with fabulous mop head, oak leaf, panicle and smooth hydrangeas. There is a hydrangea for each of us.

Sherry Blanton, “The Southern Gardener,” writes about gardening for The Anniston Star. Contact her at sblanton@annistonstar.com. Follow her on Facebook at Southern Gardener-Anniston Star.