Hydrangeas for Beginners: 7 Care Tips for Beautiful Blooms

Roses, lilacs, and hydrangeas are the trifecta of deciduous shrubs. No garden is complete without at least one, and having all three is a treat. If you were to pick one, a hydrangea is an excellent option for North American growers. There are native hydrangeas, evergreen ones, and cold-hardy specimens for every gardener, regardless of your experience.

Not only are there different species with various characteristics, but there are also varieties with many flower hues. Similar to roses, hydrangeas are a longtime favorite of plant breeders. They’ve created thousands of varieties with variegated leaves, multi-color sterile blossoms, and reblooming stems. 

Select Beautiful Blooming Species

Not only are there thousands of hydrangea varieties, but there is also a wide variety of species! Hydrangea species shrubs behave differently from each other, which can cause confusion amongst beginners trying to care for them. Some species bloom on old wood and some on new wood. They also vary in flower color, structure, height, and life cycle. Here are the most common species:

Common Name	Scientific Name
Climbing Hydrangea	Hydrangea anomala petiolaris
Smooth Hydrangea	Hydrangea arborescens
Rough-Leaved Hydrangea	Hydrangea aspera
Bigleaf Hydrangea	Hydrangea macrophylla
Panicle Hydrangea	Hydrangea paniculata
Oakleaf Hydrangea	Hydrangea quercifolia
Evergreen Climbing Hydrangea	Hydrangea integrifolia
Mountain Hydrangea	Hydrangea serrata

Overall, the most common hydrangeas are the bigleaf ones in the species Hydrangea macrophylla. They produce mophead clusters with mostly sterile flowers that sprout well in mild winter climates. Sterile flowers, although lacking in pollen and nectar, last a long time in fresh or dry bouquets. They aren’t beneficial for pollinators, but they look incredibly ornamental in your landscape. 

Three large hydrangea species are native to North America: smooth, oakleaf, and evergreen climbing. The first two, smooth and oakleaf, originate from the eastern U.S. They tolerate colder temperatures than the bigleaf kinds. Smooth varieties thrive throughout hardiness zones 3 through 9, while oakleaf types are best for zones 5 through 9. Evergreen climbing varieties grow natively in Mexico and work well in winter temperatures above 0°F (-18°C).

Climbing, rough-leaved, panicle, and mountain hydrangeas are excellent species for North American gardens. They aren’t native to the continent but thrive with the right care and conditions. Panicle hydrangeas are unique from other types—they sprout cone-shaped flower clusters larger than any other species. Train them as single-trunk trees or multi-stem shrubs.

Transplant Shrubs In Fall or Spring

Hydrangeas need cool, mild weather during transplanting to adapt readily. They set roots out when they receive continuous moisture, sunshine, and cool temperatures. The best time for transplanting is during the fall or early winter in mild winter zones.

You’ll want to transplant your shrubs in the spring if you live in a zone with frigid winters, especially if you’re growing a cold-tender species. Bigleaf hydrangeas are more frost-tender than other species, and they have a fighting chance in cold winter zones when you plant them in the spring. They function best in hardiness zones six through eleven.

Although fall or spring are the best times to transplant these shrubs, it doesn’t mean you can’t do it at other times. The only season to avoid doing this is in midsummer when days are hot and long. All hydrangea species need time to adapt to their new homes before they can resist harsh conditions. If it’s midsummer, simply wait until fall to transplant your specimens.

Use Rich, Porous Soil

Hydrangeas prefer fertile soil high in organic matter. Rich soil often contains lots of air pockets, absorbent materials, and plenty of nutrients. These benefits allow shrubs to resist droughts, freezes, and heat waves. 

If your soil is heavy clay, incredibly sandy, or low in nutrients, you’ll want to amend it before transplanting. A month before, add compost or organic mulch to the site. Mix it in with the existing soil and water, then rake it even. Let the area rest, and the amendments will inject nutrients, microorganisms, and fungi into the dirt. Then, when you transplant your shrubs, they’ll root into the soft soil and benefit from its porosity, nutrients, and crumbliness.

They also grow well in large containers, especially dwarf kinds like the oakleaf variety ‘Pee Wee’ or the bigleaf kind ‘Mini Penny.’ Give them fresh potting soil in their containers. Try to use a mix with additional drainage components like perlite, vermiculite, or coco coir. That way, your hydrangea can receive lots of water without the danger of root rot.

Manipulate Flower Color

Bigleaf and mountain hydrangeas are the two main species that change flower colors based on how much aluminum they access in the soil. Blue shades are common in acidic soils, while pink ones occur in alkaline or low aluminum ones. 

Aluminum access shifts with pH levels, meaning the higher the pH level the less aluminum these shrubs take up. Acidic soils with pH levels below 6.0 contain soluble aluminum that roots soak up easily, and excess aluminum creates sky-blue flowers. Certain nutrients also influence color, like phosphorus. Too much phosphorus locks up aluminum, causing pink flowers. 

You can use organic amendments to manipulate your shrub’s blossom color. Add garden lime to make the soil more alkaline, which causes pink blooms. You can also add a phosphorus-rich organic amendment to keep flowers pink-red. For blue blooms, add sulfur or compost to make the soil more acidic.  

Add amendments ahead of the growing season before your shrubs start to flower. They need some time to take in nutrients and shift hues. It may take up to two years for all-blue blossoms to change all-pink, and vice versa. 

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Add Fertilizer

With the right care, hydrangeas bloom heavily, producing dozens of bulging clusters annually, but beginners sometimes forget to tailor their nutrient needs. The shrubs usually benefit from organic fertilizer applications. Apply compost regularly for a slow-acting, soil-boosting effect.

Your soil may already contain the necessary nutrients. Test pH level, N-P-K ratios, and organic matter content with a soil testing kit ahead of the growing season. It will notify you which nutrients your soil needs and which ones it has too much of. Once you know what you need, you can add organic fertilizer rich in those nutrients. 

Nitrogen is the only nutrient you’ll want to be careful of applying too much. When soils are high in nitrogen, the shrubs grow many leaves at the expense of blossom clusters. Keep nitrogen low unless your soils need it.

Prune During The Correct Season

Beginners are often confused about how to properly prune and care for hydrangea shrubs to ensure an abundance of blooms. Some species bloom on year-old wood, while others bloom on fresh wood, and some new cultivars are reblooming! Prune during the right season and avoid lopping off your future flowers. Reasons to prune are for shaping, rejuvenating, and removing deadwood.

Smooth and panicle hydrangeas bloom on new wood—they benefit from late winter through early spring prunings. They start swelling their buds after putting on significant spring growth. Avoid pruning them late in spring, or you’ll cut off their flower buds.

Climbing, evergreen climbing, rough-leaved, bigleaf, oakleaf, and mountain hydrangeas bloom on old wood. They rarely require pruning except for rejuvenating old specimens. Prune them right after they bloom to shape the shrubs. Hard-prune old, wonky specimens to the ground during fall or winter; they won’t bloom the next year but will thrive for future seasons.

Protect Frost-Tender Stems

Some varieties are frost-tender, meaning they’re sensitive to freezing weather. These include bigleaf, oakleaf, evergreen climbing, rough-leaved, and mountain hydrangeas. Frozen shrubs may not bloom the next year, especially if they flower on old wood. 

Keep your tender shrubs warm by mounding compost, soil, or leaves around their base. Stack it up a few inches high so that the tender lower stems have protection. You may also use organic mulch to keep them warm. Wood chips, nut hulls, and leaf mold all maintain warmth around the base of the plants. 

The two most cold hardy species are panicle and smooth hydrangeas. They tolerate winters down to hardiness zone three and function well despite recurring freezes. Smooth hydrangeas are one of the best types for North American gardens, as they naturally grow throughout the eastern U.S. in cold regions. These two types may also benefit from warm mulch, although it’s not necessary for their survival.