Types of hydrangeas include bigleaf, oakleaf, paniculata, arborescens, and quercifolia. Hydrangeas are shrubs that have colorful flowers that bloom through summer and into fall. The colors of the flowers typically are shades of blue, purple, and pink; however, some hydrangeas have white, green, or red flowers. Most hydrangeas grow well in Zones 3-9 and prefer partial shade. There are several types of hydrangeas, which include bigleaf, oakleaf, paniculata, arborescens, and quercifolia.
Varieties suitable for zones 3-9.
There is variation in the mature size of different varieties. Some varieties only grow to be 3-feet tall and wide, while others can grow to be 15-feet tall and 12-feet wide.
Sun or shade?
Hydrangeas usually bloom best when they get some shade during the day, but some varieties can tolerate full shade or full sun. The amount of sun they can handle varies depending on where you live—in northern areas, they can take more sun, while in southern areas they prefer just a few hours of morning sunlight.
Hydrangeas generally bloom during summer, with some species blooming earlier in the season and some later (and if you’re lucky, potentially even into fall).
The majority of hydrangeas bloom in shades of blue, purple, or pink. However, there are also white, green, and even some red varieties. Some hydrangeas will open one color and then change colors as they age. Additionally, the flower color (mainly on bigleaf or mountain varieties) can be manipulated to be more blue, pink, or purple depending on the soil composition and soil pH levels. For more information on how to change the color of hydrangeas, click here.
Types of hydrangeas:
There are six main types:
- Bigleaf or French (H. macrophylla)
- Oakleaf (H. quercifolia)
- Climbing (H. petiolaris)
- Panicle (H. paniculata)
- Smooth (H. arborescens)
- Mountain (H. serrata)
In addition to different sizes, you can also choose from four different kinds of flowers: lacecap, panicle, mophead, or snowball. Some hydrangeas only bloom on old wood, some only bloom on new wood, and some bloom on both old and new wood.
When it comes to planting hydrangeas, timing, location, and healthy soil are key.
When to plant hydrangeas:
Make sure there is no threat of frost when planting container-purchased plants in spring or fall.
Where to plant hydrangeas:
- The best location is one that receives morning sun and afternoon shade. If you live further north, they will tolerate more sun (possibly full sun all day).
- Consider mature size, give it plenty of room to grow.
- Choose an area with excellent drainage. Amend the soil with compost if necessary.
- Don’t plant beneath a tree—the root competition and lack of sunlight will prevent them from thriving.
- Avoid planting in exposed areas where gusty winds could snap stems.
How to plant hydrangeas:
- Get your plant off to a healthy start by amending your soil with up to 15% organic matter and an all-purpose slow-release fertilizer (use half of what is recommended).
- Plant slightly higher than they were in the nursery container.
- The planting hole should be 2 to 3 times wider than the root ball to give the roots plenty of room for expansion.
- Gently loosen potbound roots before planting.
- Backfill with the amended soil and water well.
- If planting a grouping, space at least 3 feet apart (more, if planting larger varieties).
Planting hydrangeas in pots:
- Use a bagged potting mix rather than garden soil.
- Mix in a slow-release fertilizer.
- Leave 1 to 2 inches between the top of the soil and the rim of the pot for watering.
- Make sure the pot has drainage holes and has room for the plant to grow.
HYDRANGEA CARE & PRUNING
Do not cut off the new buds forming on your mophead hydrangeas in spring.
Most shrubs only need a little bit of pruning to remove old flowers and dead stems. Some shrubs need pruning to improve their shape or structure. Some shrubs need to be pruned to let sun and air in.
The type of plant will determine how and when it should be pruned. To prune a plant, you must first determine if it blooms on old wood, new wood, or both.
Learn more here: How to Prune Hydrangeas.
Most varieties of Hibiscus prefer soil that is rich in organic matter and well-drained. Soil composition can affect the flower color of H. macrophylla and H. serrata; other varieties can tolerate a range of soil alkalinity.
Learn more here: Changing Hydrangea Color.
It is recommended that you add a layer of organic mulch every year, or use a slow-release 10-10-10 fertilizer. Be sure to water the area thoroughly before and after you apply the fertilizer.
It is important to keep container plants moist, but not wet. They may need to be watered daily. Adding mulch will help to keep the soil moist.
Why is my hydrangea not blooming?
This is more common with types that bloom on old wood (last year’s growth). Three common reasons are:
- You may have pruned at the wrong time and inadvertently removed the stems that would have produced flowers.
- The flower buds may have been damaged by a hard frost—cover plants during cold snaps if this may be any issue.
- It could be caused by too much shade or over-fertilizing.
Common Pests and Problems
The plants can endure many hardships if they are properly taken care of outdoors. Those most commonly seen include:
- Powdery mildew
- Ring-spot virus
- Leaf spots
- Gray mold
Mold and Mildew Problems
Powdery mildew is the main problem for big-leaf varieties of plants, and it is more likely to occur if the plants are grown in very humid conditions or in deep shade.
If powdery mildew is present on your plants, you will notice a light gray, dusty coating on the leaves. Additionally, you may see some purple splotches. Although this condition will not kill your plants, it is not aesthetically pleasing. To help prevent powdery mildew, maintain a healthy environment with adequate sunlight, good air circulation, and light, well-drained soil.
Other than powdery mildew, there are a number of fungal infections that can affect this plant such as leaf spot organisms which can cause gray or brown lesions on the leaves. These may be surrounded by a purple circle of fungi. However, just like powdery mildew, these problems can be avoided and controlled if the plant is taken care of properly.
If a plant is kept in excessively wet conditions, it may develop root rot. This is especially true for oakleaf varieties. The most common type of root rot is Armillaria, which causes plants to wilt suddenly and die. To prevent root rot, plant hydrangeas in light, airy, well-drained soil and avoid over-watering.
Rust is a problem that affects their leaves from time-to-time. It manifests as orangish/brown spots on the backs of leaves. If you rub the spots, they will turn to dust which is the fungal spores. This usually happens toward the end of autumn just before the leaves fall. While it isn’t usually deadly, it can still be problematic.
You may find Japanese beetles on your oakleaf varieties, but they don’t usually come in large numbers. If you want to get rid of them, you can pick them off and drop them in a bucket of soapy water, or dust or spray your plants with an insecticide. However, most of the time you don’t need to do anything.
Infestations of aphids can occur on any type of plant early in the spring when the leaves are tender.
If you see ants on your plants, look on the undersides of the leaves and on the plant stems to see if there are aphids.
Ants tend to aphids and protect them from predators in order to harvest the honeydew that the aphids excrete.
In order to get rid of aphids and ants, spray your plants with insecticidal soap. This will also prevent them from coming back.
Aphids will be less attracted to leaves as they toughen up throughout the season.
Spider mites can become a problem during periods of drought when they are attracted to new growth to suck the moisture out of it.
If you notice new growth wilting, or if you see webbing between new leaves, it is likely that you have a mite infestation. Pruning off the affected foliage and watering your plants should help to deal with this problem. Regular watering can also help to prevent mite infestation.
Slugs enjoy all kinds of green, leafy veggies including hydrangeas. To prevent and control their predation you can use a variety of methods, including:
- Water early in the morning so that your plants will be dry at night when slugs are active.
- Set up beer traps to attract them and drown them.
- Use a flashlight and tweezers to pick them off at night.
- Use an iron phosphate slug bait for large areas.
- Surround your plants with copper strips to repel slugs and snails. In the garden, Diatomaceous earth helps control slugs, snails and a variety of other pests.
There are a few things you can do to help keep snails and slugs out of your garden. If you have a problem with snails and slugs in your garden, there are a few things you can do to help keep them out. Snails and slugs are attracted to cool, damp places, so try to keep your garden as dry as possible. If you have plants that snails and slugs like to eat, you can try putting a barrier around them, such as a ring of grit or crushed eggshells. You can also try using snail and slug traps, which you can buy at most garden centers.
Soil Related Problems
If the soil pH level is too high, bigleaf hydrangea may suffer from a deficiency of iron, which causes the leaves to turn yellow.
If the leaves of a plant turn yellow and die, the problem can be fixed by adding chelated iron to the soil. This product is easy to find at your local garden center or online.
Be sure to read and follow packaging directions carefully to eliminate the problem in the short term. In the long term, you should change the soil conditions by adding aluminum sulfate and/or mulching with pine bark or other acidic materials to lower the soil pH levels.
In addition to this, Courtenay from “The Creek Line House” also recounts her experience of using baking soda to revive a wilted hydrate.
Hydrangea As Cut Flowers
Cut your hydrangea blooms early in the day while it is cool to avoid wilting.
Do not clip very young blooms as they will not survive long. Mature flowers will last longer if you put them in water immediately. Even if you are careful, your fresh hydrangea arrangement may only last an hour or two.
Make sure to wait until the flower heads are mature and have taken on a papery texture before adding them to a dry flower arrangement. Gather the hydrangea flowers on a still, dry day.
To dry roses, remove all the leaves from the stem and hang the blooms upside down in a dark, dry, warm, and airy location. If you hang them in bunches, they will stick together and dry with squashed spots.
It is best to wait at least two weeks before using the flowers to make wreaths or other arrangements. You can enhance or change the color of the blooms by spraying them lightly with a diluted mixture of Rit dye.
If you want to create lots of interesting dried hydrangea decorations, you should seek out varieties that have naturally interesting colors. Big-leaf varieties offer the most variation, with blooms in shades of green, blue, purple, violet, and rose.
LANDSCAPING WITH HYDRANGEAS
Hydrangeas are a versatile plant that can be used in many different ways in a garden. They make good hedges and screens, and they look great in borders. They are also good for container gardening.
- White-flowered varieties create the illusion of snowballs in summer.
- Mass pink and blue types with similarly-colored garden phlox and lilies for a visual confection of candy colors.
- Blue hydrangeas look like sapphires against a gray wall or set alongside a slate patio.
- Bigleaf varieties make imposing container plants—feature a pair in large urns.
- Panicle hydrangeas can be maintained as good-sized “trees” in large pots. Learn how to grow a hydrangea tree.
- Oakleaf hydrangeas are bold and have a coarse texture that lends visual strength to shrub borders and woodland plantings.
Where To Buy Hydrangeas
Remember to check the cold hardiness of any plant you are considering to be sure that it will do well in your area.
Be sure to get plants that will do well in your climate by checking with local garden clubs and/or attending local plant sales. If you see a plants you like, find out who owns it and ask for cuttings!
If you’re looking for unusual cultivars, you can check local and online specialty nurseries to find plants that will improve your landscape.