Chose the right type of hydrangeas for your area, and these flowering shrubs will always make you smile.
Hydrangeas are some of the most popular and sought-after flowers. But because of the variety of hydrangea species, they often cause great confusion. This article will simplify these beautiful flowering shrubs and explain how to grow hydrangeas. Success with hydrangeas comes down to three things. The first is choosing the perfect type for your region. Second, planting them in the right location. And finally, knowing how to care for them.
How to Grow Hydrangeas: The Best Type for You
When most people choose to grow hydrangeas, they choose specific varieties with the flowers they want in their garden. This might backfire when it comes time to grow hydrangeas, however, because some of the species behave very differently, which affects blooming. Knowing which type you’re considering, and matching it to the weather in your area, is key to seeing flowers on your plants.
Hydrangea plants are available at most garden centers. However, a full selection of hydrangea plants can be hard to find in local stores. That’s why we have included some of our favorite website sources for these plants, including NatureHills.com and Amazon.
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Those Big Blue or Pink Mopheads
Yes, the large flowers on Hydrangea macrophylla varieties are amazing. When these plants are grown in places where the winters don’t get too cold (basically below 10° Fahrenheit) and the summers don’t get too hot (much above 90° for any length of time) these shrubs bloom well for most of the summer.
But since they form their flower buds for the following year in July or August, if the winter temperatures are too cold the germ of those blooms gets zapped. In this situation the plants grow new stems from their roots but won’t produce flowers. Even the varieties that bloom on new stems may not flower in areas where frost comes early enough to kill those developing blooms.
Those who garden in the perfect climate for mophead hydrangeas will get the most long-lasting flowers if these shrubs receive morning sun and afternoon shade. You can find mophead hydrangeas at NatureHills.com and Amazon.com.
Pruning Hydrangea macrophylla
Because the buds for the following year are already there in the summer, there is no time when you can cut the canes down that won’t affect flowering for the next season. The only pruning that should be done on Hydrangea macrophylla plants is the removal of dead canes in the spring.
Once the buds formed the previous year have started to open and there are green leaves the size of a dime, cut out any cane or top of the stems where there is no new growth. If these hydrangeas are cut back to “neaten them up” or attempt to make them smaller in the fall or the spring, you will have many fewer flowers the following summer.
How to Grow Hydrangeas: Root Hardiness versus Bud Hardiness
When it comes to the cold hardiness of Hydrangea macrophylla, there’s a difference between the root hardiness and the ability of the buds to make it through the winter. That’s why the plants may not produce flowers in colder climates.
Many of these plants are root hardy in USDA Zone 4, but the flower buds that are formed the year before won’t make it through the winter. In places where the temperatures go below 10 degrees Fahrenheit, the plants will grow back from the roots. But the flower buds on the stems will be killed. Most mopheads are root hardy in Zones 4 or 5 but only bud-hardy when winter temperatures stay above 10° Fahrenheit.
If you live in areas too cold to keep the flower buds alive through the winter, grow these magnificent plants in pots and pull them into a garage or cold basement for the winter. As long as the temperatures in the building don’t go below freezing, and you check the soil for moisture periodically, these shrubs go dormant inside and will leaf out and produce flowers the following summer. Varieties that are bred to be shorter are especially successful in pots.
Lacecaps are the hydrangeas that produce lacy flowers. They have tiny fertile flowers in the center of the bloom circled by the larger, infertile petals. These are either the mountain hydrangeas (H. serrata), or the bigleaf types (H. macrophylla). Hydrangeas in the serrata species are slightly more bud hardy than others, Unfortunately, winter temperatures in the single digits or below can still kill the buds.
Grow these lacecap hydrangeas in partial shade for the longest-lasting flowers. Like the mopheads, they are root hardy in Zone 4 to 5, but not necessarily bud hardy in those regions. Shorter varieties of lacecap hydrangeas can be grown in containers. Then, move them into the garage during the winter if you live in Zone 6 or below.
White to Pink Panicles
If you live where the temperatures dip down below zero on the Fahrenheit scale, you can still grow hydrangeas. The panicle varieties may not be blue, but they are beautiful and reliable. Unlike the mopheads and lacecaps, varieties of Hydrangea paniculata form their flower buds in the spring and early summer. The plants will still flower even if the temperature drops to -15°. Or if someone cuts them back in the fall or spring.
Some panicle-type hydrangeas have flowers that stay white most of the season. Occasionally the flowers get a blush of pink in the fall. Limelight, Bobo, and the classic PG are three varieties in this category. Other panicles turn pink, often while some petals are still white, creating a two-tone look as the flowers age. Vanilla Strawberry, Fire Light, Quick Fire, and Pinky Winky are four large-growing panicles that turn a brilliant pink as the summer progresses. Little Quick Fire and Fire Light Tidbit are two cultivars that turn pink but stay smaller. These varieties are perfect for foundation plantings and smaller gardens.
Most panicle hydrangeas are hardy in a Zone 4. Since they don’t form their flower buds the year before, you don’t have to worry about bud-hardiness. You can find hydrangeas at NatureHills.com and Amazon.com.
Grow Smooth Hydrangeas: Round White, Pink or Green
Hydrangea arborescens is another species of this shrub that produces flowers on new growth. These smooth hydrangeas are especially cold hardy. They are native to the southeast United States and are even more cold tolerant than the panicles. Although Annabelle, ‘Grandiflora’ and Incrediball are the most widely known arborescens varieties, there are new cultivars being introduced frequently.
Invincibelle Spirit II and Pinkerella have pink flowers and grow to about four feet tall. Mini Mauvette is also pink, but shorter, and Wee White only grows a foot or two high. Limetta is a newer introduction with flowers that open as a lime green and age to a softer shade of jade. Most smooth hydrangeas are hardy in zones 3-9.
The panicle and smooth varieties grow and bloom best in full to part sun. They can be pruned early in the spring by removing dead wood, crossed branches and stems that are growing into the center of the plant instead of toward the outside.
Make sure to group your hydrangea shrub with other plants that like a deep soaking every few days. Also, mulch the beds to retain moisture in the soil. Fertilize with an organic fertilizer in the spring. One application is usually enough, because too much fertility will create larger flowers that are more prone to flopping. You can find hydrangeas at NatureHills.com and Amazon.com.
This is how you grow a happy hydrangea! If you need info about fertilizing this gorgeous plants, read How to Fertilize Flowering Shrubs and Perennials.