Glorious Hydrangeas for the Summer Garden

Blue lacecap hydrangeas are garden favorites, especially ‘Nachtigall’ (singer of the night). (Image by Mike Darcy)

The name Hydrangea denotes water and comes from the Greek words, hydor (water) and aggos (a jar). Together the words mean ‘water vessel’ because of the cup-like form Hydrangea seed capsules. I have looked at the seed capsule, and perhaps my imagination is not quite enough to describe them as water vessels, but hydrangeas do require regular soil moisture to look their best. Give them basic care, and they are some of the easiest summer-flowering shrubs you can grow.

As with many groups of plants, Hydrangeas are very diverse in flower color, leaf color texture, and growth habit. Their flowers can be different shapes and colors will vary from solid colors of white, pink, blue, purple, and cream to some that are bicolor in shades of pink and white. Leaf color is also variable and while most are solid green, some are variegated and some have burgundy foliage. They thrive throughout much of the Pacific Northwest and in many other parts of the country, except for areas with extreme summer heat or winter cold, and some species are not adapted to the deep South.

Hydrangea Selection

Tuff Stuff is a compact lacecap known to prosper in more difficult growing areas. (Image by Jessie Keith)

Selecting a hydrangea for the garden can be difficult because there are so many choices. It is difficult to only select one! Space is limited, and I cannot name all of my other favorites, but here is a selection of favorites from my garden.

Oakleaf Hydrangea

‘Snow Queen’ is my favorite oakleaf hydrangea. (Image by Mike Darcy)

If I had to pick just one hydrangea to grow, my choice would be Snow Queen oakleaf hydrangea (Hydrangea quercifolia ‘Snow Queen’). It is named because of the oak-like shape of the leaves and snowy summer flower clusters. This hydrangea is a sturdy grower with white upright panicles of single blooms that cover the plant in early to midsummer. It has deep green leaves all summer and in the fall, they turn a superb shade of red. Another plus is that oakleaf hydrangeas tend to take more sun than many other species.

Lacecap and Mophead Hydrangeas

‘Nachtigall’ has some of the best blue lacecaps. (Image by Mike Darcy)

Common bigleaf hydrangeas (Hydrangea macrophylla, USDA Hardiness Zones 6-11 (a few cultivars are bred to survive to Zone 5)) and mountain hydrangeas (Hydrangea serrata, Zones 5-9) have either mophead (with a puffy head of showy flowers) or lacecap (with a head showy flowers along the margins) blooms. Mopheads are more common, but I prefer lacecaps for their stately appearance. Their flowers are in shades of blue, pink, white, red, or purple. The blue/purple or pink/red types have flower colors that can change depending on the pH of the soil. Pinkish/reddish colors denote more alkaline soil, and purplish/blueish colors indicate more acidic soil.

One of the deepest blues of the lacecap types, and a spectacular specimen in my garden, is Hydrangea macrophylla ‘Nachtigall’ (5 feet x 5 feet). I first saw one in a garden last summer, and I kept walking back to it because it was such an impressive large shrub in full bloom. Some of the flowers looked as though they were almost double. Another I have had my eye on is a compact, pink-flowered lacecap called Tuff Stuff (3 feet x 3 feet) from Proven Winners. It is supposed to be exemplary and has a neat, rounded habit.

Three more favorite hydrangeas are known for both their foliage and flowers. They are the lacecap ‘Lemon Wave’, which has leaves with patches of white and yellow, the bigleaf lacecap called ‘Purple Leaf Form’, with its truly burgundy foliage, and a dark-purple-leaved mophead called Eclipse® with showy red and white flowers. All are striking in the garden and cause my visitors to comment.

Smooth Hydrangea

‘Annabelle’ is one of the prettiest smooth hydrangeas. (Image by Mike Darcy)

For large blooms, the native Annabelle smooth hydrangea (Hydrangea arborescens ‘Annabelle’, 3-8) is hard to beat. It is sometimes referred to as an old-fashioned snowball plant. The buds begin as pale white or light green and open to white. The blooms are very large, and the plant has a long blooming period in the summer.

Climbing Hydrangea

Schizophragma hydrangeoides ‘Moonlight’ is a lovely woody vine for shade. (Image by Mike Darcy)

While technically not a Hydrangea, climbing hydrangea (Schizophragma hydrangeoides ‘Moonlight’, Zones 5-8) is a close relative. The climbing lianna tolerates shade. In my garden, it only receives about an hour of morning sun and looks beautiful. Its heart-shaped leaves are almost silver and the lacy summer flowers are ivory.  Climbing hydrangea stems are stout and develop rootlets that attach to buildings, walls, or pergolas, so plant yours on a structure with strength and permanence.

Hydrangea Care

Hydrangeas like moist, not soggy, soil. Select a site that is protected from the hot afternoon sun. Morning sun or filtered sunlight is ideal. Water thoroughly, especially during the first year, and don’t let the soil become dry. At planting time, add a liberal amount of Black Gold® Natural & Organic Garden Compost Blend to the soil beforehand to increase organic matter. When planting hydrangeas in large pots, use Black Gold® All Purpose Potting Mix. Then add Black Gold® Perlite for increased drainage and aeration.

Eclipse® has both showy leaves and flowers. (Photography by Tracy Walsh, care of First Editions® Shrubs & Trees)

Hydrangeas species and varieties have different pruning needs. Some of the older cultivars bloom on second-year growth, and if heavily pruned in the fall, the plants will skip a year of bloom. Some bloom on new growth, so the time of pruning is not so critical. Those that bloom on new growth include the panicle hydrangea, which is not mentioned above (Hydrangea paniculata ‘Limelight’ is a good variety to try), and smooth hydrangea. Check the plant tag for pruning requirements. (Click here for more pruning guidelines from Proven Winners®.)

There are so many hydrangeas to choose from, and given the right planting conditions they can provide beauty in the garden for many years. A good rule of thumb as to how particular plants will perform in your garden is to talk with friends or neighbors who have them. If their plants are thriving, yours should, too. The month of May is an excellent time to plant. For more Hydrangea information, contact the American Hydrangea Society.

What Container Hydrangeas Will Grow Well in Partial Sun?

What Container Hydrangeas Will Grow Well in Partial Sun?

“I’m in a duplex, and I only have access to either morning sun or full evening sun for my containers. Which is best for hydrangeas in pots?” Question from Jack of Claremore, Oklahoma

Answer: Several compact, hardy hydrangeas will grow well in both light settings in your USDA Hardiness Zone 6 garden. Here are three tiny hydrangea varieties that I know will perform very well in either situation. (All just happen to be Proven Winners varieties, because they arguably carry the best hydrangeas.)

Container Hydrangeas for Partial Sun

1.Bobo® Panicle Hydrangea: Grow this variety in the location with the most sunlight. In summer, Bobo produces loads of white, upright flower panicles that age to rosy pink before they dry to tan in late fall. It ultimately reaches 3 feet high and 4 feet wide, so it needs a large container for the longterm. A half wine barrel would be a good size.

2.Invincibelle Wee White® Smooth Hydrangea: Smooth hydrangeas can take a little more shade. Wee White is a teeny hydrangea below 3 feet with mop-type flower clusters in summer.

3. Invincibelle Mini Mauvette® Smooth Hydrangea: If you like rosy pink flowers, then plant this 3-foot beauty. Its rosy pink pompon flowers will light up a container.

I recommend planting these in Black Gold Natural & Organic Ultra Coir, which is OMRI Listed for organic gardening. If you are planting for the longterm, I always recommend adding at least one part ground or topsoil to two parts potting soil. The combo will allow the plants to remain in the container for longer without needing to have the mix changed. Follow up by feeding with Proven Winners Continuous Release Plant Food.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

When Do You Prune Hydrangeas?

When Do You Prune Hydrangeas?

“When is the best time to cut back my Hydrangeas?” Question from Marlene of Lapeer, Michigan

Answer: When do you prune hydrangeas? It depends entirely on the type of hydrangea you are growing. Some bloom on new wood, some bloom on old wood, and still others bloom on new and old wood. Let me break it down by common species to make it simpler.

When to Prune Different Hydrangeas

Smooth Hydrangea (Hydrangea arborescens, USDA Hardiness Zones 3-9): Prune these hardy, resilient hydrangeas at any time. They bloom on both new and old wood.

Mophead and Lacecap Hydrangeas (Hydrangea macrophylla varieties, zones vary): Prune these hydrangeas in midsummer just after they bloom, if pruning is needed. They flower on second-year wood. Hardiness zones vary anywhere from 5-11, and mopheads tend to die back in their most northern ranges of hardiness, so they are not the best option for colder gardens where their flowers may be frozen back each year. Please check the hardiness of any variety before planting it.

Oakleaf Hydrangea (Hydrangea quercifolia, USDA Zones 5-9): Prune these hydrangeas in midsummer just after they bloom, if pruning is needed. They bloom on second-year wood.

Panicle Hydrangea (Hydrangea paniculata, USDA Zones 3-8): Prune panicle hydrangeas in late winter or early spring. They bloom on new wood.

Lots of newer reblooming hydrangea varieties bloom on both new and old wood, so they can be pruned at any time. Also, keep in mind that any dead or dying stems should be cut off to keep shrubs looking clean and attractive.

I hope that this information helps!

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Can I Grow Hydrangeas in Central Florida?

“I live in Central Florida, zone 9b, can I grow hydrangeas in this zone? I used to have them in Maryland as they are my favorite flower. Not sure about the sandy soil here.” Question from Eileen of Longwood, Florida

Answer: Many hydrangeas require cold winters to survive, but there are some truly beautiful hydrangeas that will grow well way down South. These are bigleaf hydrangea (Hydrangea macrophylla) varieties. (Click on this link to view many excellent bigleaf hydrangeas from Proven Winners.) Keep in mind, you are right on the most southerly edge of their heat tolerance. They are able to survive in USDA Hardiness Zones 5-9, so you will want to give them extra good care at planting time and protect them from scorching heat.

To keep your hydrangeas protected from the high heat of the day, plant them in a partially shaded location on the north side of your home, and amend the soil heavily with organic matter. Black Gold Canadian Sphagnum Peat Moss and Black Gold Garden Compost Blend will really boost levels of water-holding organic matter. Follow up with a 2- to 3-inch layer of fine bark mulch or pine straw to reduce surface evaporation. If you experience any dry periods, be sure to irrigate your shrubs as needed. It also pays to feed them with a quality fertilizer formulated for flowering shrubs.

Happy hydrangea growing!

Jessie Keith

Black Gold Horticulturist

Why Isn’t My Hydrangea Flowering?

“I have hydrangeas but each year they only get leaves and no flowers what can I do?” Question from Nancy of Campbell, Ohio

Answer: Generally when gardeners have trouble with hydrangeas that refuse to bloom, they are largeleaf hydrangeas (Hydrangea macrophylla hybrids). These survive just up to USDA Hardiness Zone 5, your zone, but you should be able to get them to bloom.

Largeleaf hydrangeas bloom on “old” or last year’s stems, so it is important not to prune them back in spring or fall. If trimming is needed, they should only be pruned right after they flower in summer. On occasion, harsh winters will cause stem dieback–killing all of the flowering stems down to the ground. Deer can also nibble them. When this happens, expect few to no flowers that year.  (Click here for an excellent schematic by Proven Winners that visually explains why some hydrangeas won’t bloom.)

Another factor is that largeleaf hydrangeas bloom best in partial sun. If yours is in deep shade, consider moving it. In your zone, the best garden spot for a largeleaf hydrangea is a partially sunny, protected location. Planting it near a building or wall will give it some protection from the harshest winter weather.

If you don’t feel like bothering with all of these steps, we recommend planting smooth hydrangea (Hydrangea arborescens) varieties, which are very hardy and bloom on new wood. Two really exceptional types are Incrediball® and Invincibelle® Ruby. These grow best in fertile soil and like the addition of fertilizer formulated for flowering shrubs. I recommend amending their planting hole with Black Gold Garden Soil, which feeds plants for up to six months.

I hope that these tips help!

Happy hydrangea growing,

Jessie Keith

Black Gold Horticulturist

Why Didn’t My Hydrangeas Flower and Why Do They Have Spots?

“My hydrangeas didn’t flower this year and also have “black/brown” spots on the leaves.  Any ideas on what to do?” Question from Debra of Saint Inigoes, Maryland

Answer: Mophead or lacecap hydrangeas (Hydrangea macrophylla) are prone to fungal leaf diseases when there is excess moisture and the shrubs are poorly aerated. And, there are a couple of reasons why hydrangeas fail to bloom. 

Hydrangea Leaf Fungal Diseases

Do the spots on your plants look small, roundish, and purplish brown with lighter centers? If so, then they have the common disease, Cercospora leaf spot. It is not deadly, but it is unsightly and can eventually cause leaf drop. If your spots are larger, greyish, and more irregular, then your shrubs are suffering from Anthracnose spot. This appears when weather is excessively rainy and hot.

Both diseases take hold in spring but do not become visually apparent until later in the season. The best way to manage them is to clean old and diseased leaves diligently, and selectively prune to help aerate plants, which will reduce the onset of the disease. Also, refrain from overhead watering, which can further spread leaf spot.

Remove select stems down to the ground within your hydrangeas to encourage airflow, and if only a few leaves are spotty, remove them as you see them. Any fungicides you might use would be strong and not 100% effective at this stage, so I do not recommend them. In fall, be sure to remove all of the leaves that fall to the ground, and apply a fresh layer of mulch around them. Next year, keep an eye on your plants and remove any spotty leaves as you first see them.

Some hydrangeas resist spot diseases. These include the varieties ‘Veitchii’ (whitish flowers), ‘Pretty Maiden’ (soft pink flowers), ‘Ayesha’ (pink or blue white-centered blooms), and ‘Tovelit’ (brilliant pink or violet-blue flowers). If you continue to have lots of trouble, remove your hydrangeas and plant one of these.

Why Hydrangeas Fail to Bloom

Leaf spot will stress plants and can reduce bud set, but it should not totally keep hydrangeas from blooming. Two of the most common reasons hydrangeas fail to bloom in a season are 1) improper pruning or 2) winter dieback. If you prune Hydrangea macrophylla, then it is important to cut back the old blooms right after they flower. Otherwise, you may cut next year’s flower buds off. (Click here on a full tutorial on how to prune many different types of hydrangeas.) The same thing can happen if your shrubs suffered winter dieback. Sometimes late freezes damage the flower buds in spring as well.

I hope that this information helps. Please let me know if you have any additional information.

Jessie Keith

Black Gold Horticulturist

Summer Hydrangeas in the Garden and More

The brilliant white flowers of Snow Queen oakleaf hydrangea will brighten any summer garden, day or night.
The brilliant white flowers of Snow Queen oakleaf hydrangea will brighten any summer garden, day or night. (Photo by Jessie Keith)

It has been a busy summer with many exciting activities! Aside from my normal radio, writing and garden work, there have been garden tours, talks and even contests to take part in. On June 29, my garden was one of five private gardens open for Garden Conservancy Open Garden Days in the Metro Portland Area. The Garden Conservancy is a national organization dedicated to preserving and helping to maintain both public and private gardens throughout the United States. (For example, one of their current ambitious goals is to restore the gardens on Alcatraz Island.) The admission fees collected for their Open Garden Days, $5 per garden entry, go to support their cause. Continue reading “Summer Hydrangeas in the Garden and More”

Hydrangea 'Shooting Star'

Hydrangea Shooting Star I think a plant makes an especially nice winter gift for the gardener if it is blooming and so can be enjoyed indoors and then later planted in the garden. Hydrangeas from a garden center (not a florist) are usually good choices. One of my favorites is Hydrangea ‘Shooting Star’. It blooms for a long period indoors and once spring has arrived, can be planted in the garden as a permanent plant.