Hydrangeas are not just known for their beautiful blue summer flowers, but they offer a lot more. With their striking shades of blue, purple, red, pastel pinks, and rich creams against deep green leaves, hydrangeas are a wonderful addition to any garden. They are easy to grow and a great choice for novice gardeners who want to make a significant impact in their garden. These shrubs are eye-catching and can be planted alone or complemented with low-growing perennials such as Heuchera, Nepeta, Hosta, Salvia, or any other combination that you can think of. Whether clustered together or climbing up a trellis, hydrangeas are resilient and their stunning blooms can be enjoyed wherever they are planted.
Plant Classification
Plant Category: Shrub or Vine
Seasonal Preferences: Summer until early fall
Common Pests: Aphids, beetles, and spider mites
Family Name: Hydrangeaceae
Genus: Hydrangea
Species: Hydrangea spp.
Exposure to Sunlight: Partial Sun
Common Diseases: Fungal diseases
Time Until Maturity: Three to four years
Maintenance Level: Medium
Rate of Growth: Rapid
Soil Type: Well-draining and acidic soil
Native Area: Asia
Spacing between Plants: Depends on the variety
Attractions: Pollinators and common wildlife
Hardiness Zone: USDA zones 3 to 7
Good Companion Plants: Low-growing perennials and annuals
Plants to Avoid Planting Near: Lavender and deep shade plants
Depth of Planting: Equivalent to the depth of the root ball
Watering Requirements: Moderate
Height of Plant: Dependent on the variety
Plant History: N/A
Hydrangeas have a long history of growth in Japan, where they were first cultivated thousands of years ago. Today, they can still be found growing wild in the mountainsides of Japan. The journey of hydrangeas to North America remains a mystery, but fossils dating back 40-65 million years ago have been discovered in North America. In Europe, the flower gained popularity and was named Hydrangea because of the shape of its flower, which reminded botanist Grovonius of an ancient water pitcher. Hydrangea root has been used for centuries to treat bladder-related issues, although it is not a popular herbal remedy. Hydrangea stems have become popular in floral bouquets, symbolizing gratitude, unity, and togetherness.
Hydrangeas belong to the family Hydrangeaceae and are a versatile plant with over 70 different species. They can be used in various ways such as landscaping, lining walkways, peeking through fences, in large containers, and even as a foundation planting or tree form. The six most popular species found in North America and Europe are the smooth hydrangea, bigleaf hydrangea, panicle hydrangea, oakleaf hydrangea, mountain hydrangea, and climbing hydrangea, each with distinct differences.
When it comes to propagating hydrangeas, there are two common methods: cuttings and layering. These methods are relatively simple and have similar success rates. To propagate using cuttings, take a cutting of the desired stem and remove the lower leaves. Dip the cut end in rooting hormone and place in a pot filled with a well-draining soil mix. Keep the soil moist and wait for roots to develop before transplanting into its permanent location.
Growing hydrangeas through cutting stems is a favored method of planting this popular plant. To start this propagation process, find a green branch or stem that has not yet bloomed in the current season and cut it to about five to six inches in length while leaving a few sets of leaves intact. Remove the bottom two sets of leaves to expose two leaf nodes, which will serve as the growth point for the new plant. Use any sterile type of medium, such as coarse sand or vermiculite, to fill a container and dip the bottom of the cutting into rooting hormone powder, which is optional but increases the chances of successful rooting and protects the cutting from unwanted diseases. Gently press the cutting into the soil, water it well, and allow the water to drain out of the pot. Cover the cuttings and the pot with plastic to create a greenhouse-like atmosphere and keep them in bright light, without direct sunlight, until the top of the soil feels slightly dry. It will take about two to three weeks for the hydrangea cuttings to root. At this point, you can transplant them into larger pots or directly into the ground.
Hydrangeas can be propagated easily through ground layering, which is a fun and simple process that can be done in your own garden. To start, choose a branch close to the ground and remove the leaves from around five inches of the area where it will touch the ground. Then, scratch some bark off the underside of the branch in the same area and make sure at least one leaf node will be under the ground. Afterward, dig a small hole around two inches deep and place the branch into it. Cover generously with garden soil and use a stone or brick to keep it in place. Water occasionally until roots begin to form on the stem where the incision was made. Once the new plant has established roots, cut it from the mother plant and move it to a new location in your garden. Let it stay in place for one to two weeks before transplanting to give it time to adjust to its new environment.
Hydrangeas are most commonly purchased in small pots from a nursery and then transplanted into the garden. However, I prefer to buy mine from plant sales at local botanical gardens, where they are typically grown from cuttings. You can find many different varieties available in all sorts of sizes at nurseries and garden centers. The same planting process will work for mature cuttings as well.
When selecting the perfect plant, make sure to keep the mature size of the hydrangea in mind. This will reduce the amount of pruning you might need to do later on. Before digging your hole, water the plant while it is still in its container to prevent any transplant shock. Dig a hole twice as wide as the size of the pot and amend the soil with compost or peat if it is dense or clay-like. Do not plant deeply; keep the base of the plant at the same depth as it is in the nursery pot. Water it well immediately after planting and continue to water until it is established.
When growing hydrangeas, there are many things to take into consideration. You want to ensure that you have enough light, water, and the right climate. If planting with other plants, consider hydrangea companions that won’t compete for nutrients. You also want to make sure your soil conditions are favorable and use recommended fertilizer when it’s time to feed your plant.
Hydrangeas grow best in partial shade, so it’s recommended to plant them in areas where they can receive shade during the beginning and end of the day. While all hydrangeas can grow well in partial sun, especially in areas with morning sun and afternoon shade, this is particularly true for the macrophylla species. However, if you have more sunlight, you may want to consider planting the paniculata species which can tolerate sun throughout the day as long as there is enough moisture. It’s important to water your hydrangeas regularly to ensure healthy growth.
Hydrangeas thrive on moderate watering, best done in the morning at the base of the plant. Once established in the ideal location, watering should be minimal. To avoid the stress of summer heat, hydrangeas should be watered in the morning. Signs that your hydrangea needs water include withering flowers and drooping leaves, which can be remedied with a good soaking. Watering should be aimed at the base of the plant and soil to prevent fungal diseases, which hydrangeas are highly susceptible to. Drip irrigation is the best watering option for hydrangeas as it keeps the flowers and leaves dry but well-watered. Keeping an eye on the weather is crucial, and if it’s particularly hot, more frequent watering may be necessary. In any case, pay attention to the leaves, which will indicate when watering is needed.
For optimal growth of hydrangeas, it is recommended to use well-draining soil with an acidic pH. It is important to avoid waterlogged soil as this can harm the plant, but ensuring adequate hydration can be achieved by adding organic materials like compost, peat or dried leaves. As hydrangeas prefer acidic soil, it’s important to consider this factor when selecting the soil. Additionally, climate and temperature are other factors that can impact the growth and health of hydrangeas.
Hydrangea gardens thrive in mild climates with moderate temperatures. These hardy perennials can typically be grown in USDA zones 3-7. While most variations of hydrangeas flourish in these zones, some have also been known to succeed in warmer climates. In warmer regions, the plants may not have a chance to go dormant and prefer more shade and frequent watering. When fertilizing your hydrangeas, it is important to follow specific instructions for the type of fertilizer being used to ensure optimal growth and health.
Hydrangeas thrive on slow-release fertilizers applied in early summer. Once established, they don’t require extensive fertilization. Using manure or compost around the plant’s base is the best way to fertilize hydrangeas and improve soil conditions over time. If you opt for chemical fertilizer, choose one labeled for trees and shrubs, and look for slow-release formulas. Cover the slow-release granules with soil before application to ensure proper release. A 10-10-10 fertilizer is also an option, but avoid fertilizing hydrangeas after August as the plants prepare to go dormant. Regular maintenance is key.
Hydrangeas require minimal maintenance during summer, mainly watering. If the shrub blooms prolifically, I cut flowers for arrangements and try to make it a two-for-one task by cutting it where I would like it to be pruned the following season. When frost hits, the leaves turn yellow and fall to the ground, which should be removed by hand or using a small rake. It is advisable to wear long gardening gloves while clearing the base of the plant to clear any leaf litter that could be diseased and provide air circulation to keep fungi away. In areas where temperatures drop below five degrees during winter, it may be necessary to protect the hydrangea. Insulate the plant using something that does not compact too easily, such as pine straw or dried oak leaves. Use stakes and chicken wire, leaving enough room so that the wire does not rub against the plant. An upside-down tomato cage can also be used if the hydrangea plant is small enough.
The timing of when you should prune your hydrangeas depends on the species that you have in your garden. It is important to consider which species you are working with while pruning. Some species bloom on “old wood,” which is any growth from the previous season, including macrophylla, serrata, quercifolia, and anomala. Old wood species do not require a lot of pruning and are best left to grow freely, with pruning only for containment and to remove winter kill. Quercifolia can be pruned until April, while it is best to prune anomala after flowering in late June by merely removing the spent blooms. Macrophylla and serrata both have big heads of flowers, one mophead, one lace, and respond to the same type of pruning. On the other hand, some species bloom on “new wood,” which is the growth from the current season, including arborescens and paniculata. If you’re working with a new wood bloomer, it is best to prune them in late fall.
There are numerous hydrangea varieties, many of which perform well in full sun, and some even grow well in partial shade or full shade. Let’s explore some of the most popular varieties, such as Hydrangea macrophylla ‘Nikko Blue.’
The Nikko Blue hydrangeas are a stunning addition to any cottage garden, bringing a beautiful blue hue. Nothing can quite compare to the classic beauty of Hydrangea macrophylla ‘Nikko Blue’. With their mop head blooms, these hydrangeas have long-lasting flowers in shades of blue that are a staple of New England gardens. They’re an easy way to give your outdoor space a cozy cottage feel. These blue hydrangeas are also very popular and commonly found in gardens along the East Coast. Another variety of Hydrangea macrophylla that’s worth considering is ‘Lady in Red’.
The Lady in Red is a unique type of hydrangea that produces vibrant dark pink to red blossoms. Among a sea of blue and purple blooms like the Hydrangea macrophylla, the Lady in Red stands out as a show stopper in any garden. Although it belongs to the same species as the mophead hydrangea, this lacy cap variety offers a great contrast to your garden. During early summer, this hydrangea begins its season with light pink flowers that mature slowly to a deeper pink or even occasionally a blue color. Before the blooms appear, the plant boasts red stems and red veins in its green leaves. Another noteworthy variety of hydrangea is the Hydrangea paniculata ‘Limelight’.
The Limelight hydrangea is a great addition to any garden, with its unique green flowers. This particular variety, known as Hydrangea Paniculata ‘Limelight’, can grow up to 6-8 feet tall, making it an ideal choice for those looking for privacy planting options. The cone-shaped blooms of this plant can range in color from cream to light green, and even pink, with some blooms featuring a combination of these colors.
