“What’s the best way to ensure that my blue [bigleaf] hydrangea stays blue?” Question from Gaye of Saint Peters, Missouri
Answer: It all has to do with soil pH. There are two hydrangeas that have flowers whose color changes depending on whether the soil is acidic (3.5-6.8), alkaline (7.2-10), or neutral ( around 7). These are bigleaf hydrangeas (Hydrangea macrophylla, Zones 5-11) and Japanese mountain hydrangeas (Hydrangea serrata, Zones 6-9). If your flowers are on the pinker side then your soil is more alkaline, and if they are erring towards purple then your soil is more neutral. To achieve flowers with a bluer hue, you will need to lower your soil pH. There are several ways to do this.
We’ve had a long hot and dry summer here in the Pacific Northwest, so those plants that relish the sun and take drought have performed beautifully. In turn, shade lovers, that thrive in cool, moist environments have needed extra care. In my garden, we have a mix of areas with blazing afternoon sun, almost total shade, and both sun and shade. I have banked on a large selection of shade plants to provide color in the form of foliage as well as flowers in my full and partially shady areas, and as summer wanes, I count on certain fall bloomers to keep my shade gardens looking sharp.
Reblooming hydrangeas are the first group of plants that come to mind for late-summer and fall color in the shade garden. While many will tolerant some sun, I think they look their best, and the flowers last much longer if the plants are grown in afternoon shade. Bigleaf hydrangea (Hydrangea macrophylla, Zones 6-9) and mountain hydrangea (Hydrangea serrata, Zones 5-9) are some of the best adapted to shade, and rebloomers flower the most reliably into fall. One excellent selection to try is the large-panicled Let’s Dance®Rhythmic Blue®reblooming hydrangea, which reaches 4 feet by 4 feet and produces big violet-blue (or pink in more alkaline soils) flower clusters well from midsummer to fall. Another is the very compact 3-foot Tuff Stuff Ah-Ha® reblooming mountain hydrangea with its lacy pale-blue flowers. It grows well in-ground or in well-drained containers filled with a quality mix, like Natural & Organic Black Gold Flower & Vegetable Soil.
Good water is essential. If the plants become stressed for moisture, often the flowers will turn crisp, especially when in the hot sun. Despite our tough summer, hydrangeas have thrived when given adequate moisture and some protection from the sun. When I walk around my neighborhood, I see gorgeous hydrangea flowers on those plants that have been given the right care. This is where a good mulch will also help keep the plants hydrated and happy. Black Gold Garden Compost Blend is an ideal water-holding soil amendment as well as mulch.
Another popular and well-known flower for partial shade is fuchsia (Fuchsia hybrids, Zones 9-11). ‘DebRon’s Smokey Blue‘, with its dark rose and purple flowers, is a personal favorite. Mine have been blooming all summer and will continue well into the fall. We have fuchsia plants in containers on our deck that are covered with flowers and have many buds yet to open. While the flowering will not be as prolific as it is now, they should continue to bloom until frost. Some fuchsias have the addition of colorful variegated foliage, so the plants can be colorful even without flowers. With their brightly colored flowers and foliage, fuchsias provide quite a show in the autumn shade garden.
Hardy fuchsia (Fuchsia magellanica, 6-10 feet, Zones 6-9) is an Argentinian shrub that blooms from summer to fall with many small, red and pink, pendulous flowers that feed migrating hummingbirds. While many of the hardy fuchsias will grow in the sun, I’ve found that they perform better without the hot afternoon summer sun. It is wise to place hardy fuchsia near the home or protective stone walls to provide it extra winter protection.
A new plant for me this year is palm leaf begonia (Begonia luxurians, Zones 9-11). The leaves are very tropical looking, and it has been in bloom during the past month with clusters of white and yellow flowers. I have my plant in a container with Black Gold Natural & Organic Potting Mix. It’s in an area where it only gets filtered sunlight because of overhead trees. It was about 12 inches tall when I bought it in early June and has now grown to 4 feet. Technically a perennial, it would be treated as a summer annual here or could be brought indoors as a house plant in a sunroom or greenhouse. It would not survive our winters outdoors.
Yellow Wax Bells
Yellow wax bells (Kirengeshoma palmata, Zones 5-8) is a perennial in the hydrangea family that is native to eastern Asia. It is quite a mouthful to say in Latin as well as to remember. While the common name, yellow wax bells, is much easier to remember and say, it is not well known and would be hard to find in most garden centers under that name. I rarely see it in local gardens, and I don’t know why. It grows beautifully for me. A plant was gifted to me many years ago. I have it in a shady location, and it thrives.
The plant itself is about 4 ft tall and wide and is coming into bloom now. Its waxy yellow flowers are very pretty and look attractive against its large, bold, palm-shaped leaves. It likes shade and moisture and is winter hardy. I mulch it regularly with Black Gold Garden Compost Blend.
This is just a sampling of plants that give late summer color to shaded gardens. To add to the list, I have written about fall anemones (click here to read), dahlias, some other favorite fall-flower picks (click here to read). Check out your local garden center, and you may be surprised at the large selection of blooming plants that are still available.
“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 ofClaremore, 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.
“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 am looking for possibilities for flowering accent shrubs (other than roses) for the front of house landscaping. I’d prefer something that blooms throughout the summer if it exists. My Zone is 6a.” Question from Diana of Fort Wayne, Indiana
Answer: There are several flowering shrubs with a long season of bloom that will grow beautifully in your USDA Hardiness Zone 6 climate. Here are four recommendations that are easy and attractive.
Flowering Shrubs for Foundations
1. Smooth Hydrangea varieties (Hydrangea arborescens): Tolerant of sun and shade, smooth hydrangeas are very hardy and native to your region. Some of the new varieties bloom for a long time in summer, and then their blooms remain on the plants and continue to look pretty into fall and winter. I love the many varieties sold by Proven Winners, such as their Invincibelles, among others. (Click here to view them.)
2. Abelia (Abelia hybrids): Abelias bloom and bloom through summer with small flowers of pink or white. Many also have colorful foliage and some are semi-evergreen. Ruby Anniversary is a wonderful compact selection with loads of tiny pink and rose flowers that I have growing in my front yard. Kaleidoscope abelia is another beauty with multicolored leaves and pretty little blooms.
3. Reblooming Yellow Potentilla (Potentilla fruticosaHappy Face®): These mounding 3-foot shrubs bloom all summer with golden yellow flowers. The foliage is very fine and plants are sun-loving.
4. Reblooming Azaleas (Rhododendron spp.): Encore® and Bloom-A-Thon® Azaleas will rebloom and some are even evergreen. I recommend them if you have slightly acid to acid soils with good drainage.
All of these flowering shrubs are tidy and look smart when interplanted with evergreens and perennials. All will become established more quickly with soil amended with Black Gold Garden Compost Blend. I hope that you like these suggestions.
“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.
“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.
“Some tips please – I planted a Hydrangea, and it lasted just a couple of weeks. I love the plant and would like to try again. Help!” Question from Rita of Dinuba, California
Answer: Hydrangeas are lovely when they are blooming at their prime, but many can be finicky, especially when it comes to soil and moisture levels. I see that your city has a USDA Hardiness Zone of 9, and Sunset Climate Zone 8. Your hot, arid summers and cool, wet winters don’t favor the needs of standard mophead or lacecap hydrangeas (Hydrangea macrophylla). These survive in USDA Hardiness Zones 5-11, but they are really moisture-needy plants.
This doesn’t mean that you lack options. There are three possible solutions to consider.
1. Plant the tougher, more drought-tolerant panicle hydrangea (Hydrangea paniculata) in a protected spot in your yard and give it lots of care through summer. There are many beautiful varieties, such as the large, bushy ‘Limelight‘, which has greenish-ivory flowers, and the compact ‘Pinky Winky‘, which has ivory blooms that darken to deep pink as they age. I suggest planting panicle hydrangea in a partially shaded location on the north side of your home and amending 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 or leaf mulch to reduce surface evaporation. Try to plant your hydrangea where it will be protected from the midday sun. Even though this hydrangea is tougher, it will still need to be irrigated regularly throughout summer.
2. Attempt to plant a mophead or lacecap hydrangea (Hydrangea macrophylla) as you would the panicle hydrangea but give it even more water and care.
3. Plant a variety of the California Lilac (Ceanothus spp.), which is native to your state and has bold clusters of violet-blue or white flowers that rival those of hydrangea. The variety ‘Concha has extra pretty violet-blue flowers, and the flowers of the compact ‘Mill’s Glory‘ are forget-me-not blue. California Lilac would be the easiest option because the plants are best adapted to your climate. (Click here to read more about growing California lilac.)
“What am I supposed to do with my potted hydrangea in the winter? It’s too big to move around. I did cover it with leaves and pine needles. It lost all its leaves. Is that normal?” Question fromKriss of Steilacoom, Washington.
Answer: Most hydrangeas are deciduous, which means they drop their leaves in winter. Potted specimens are most often big leaf hydrangeas (Hydrangea macrophylla), particularly in the mild regions of the Pacific Northwest. They display big clusters of showy blue, pink, or white blossoms in summer and have large, robust green leaves. There are many cultivated varieties of these hydrangeas that vary in hardiness, most withstand winters in USDA Zones 6b to 9, so they should be well protected in your USDA Hardiness Zone 8 or Sunset Zone 5 location. In areas with colder winters, they can survive but typically die to the ground and don’t reliably flower. This is because they typically bloom on the previous year’s wood.
It sounds like you are doing the right thing. Protect your container specimen through the winter with protective cover, like leaves, straw, and needles. When the leaves start to appear on the stems in the spring, remove the cover, and keep a lookout for any stem dieback. If there are any dead stems, cut them off to keep your specimen looking nice. If you want to shape the shrub for good looks, wait to prune further until it has finished blooming. (Click here for a full tutorial on how to prune hydrangeas).
Otherwise, keep your shrub watered, fertilized, and replenish old mix with a quality outdoor potting mix, such as Black Gold® Moisture Supreme Container Mix. These shrubs grow best in full sun to partial shade.