Guide to Growing Hydrangeas in Pennsylvania

Hydrangeas are trending plants (especially Limelight hydrangeas), and it’s easy to see why.  Homeowners and gardeners across Pennsylvania love these perennials because they offer an explosion of color and cottage charm that elevates a home’s curb appeal.  Plus, many varieties of hydrangeas have color-changing flowers.

If you want lush, gorgeous color, then hydrangeas are for you whether you’re a seasoned gardener or just starting your gardening journey.  So, here is our guide to help you grow the best hydrangeas.

Why You Should Grow Hydrangeas

Pennsylvania gardeners choose hydrangeas to have reliable perennials that get fuller and more beautiful each summer.  This also means that hydrangeas make for great flowering privacy screens, hedges, and bold border plants.  You can also use hydrangeas as focal points in your landscape or use dwarf hydrangeas in patio containers to add touches of bountiful flowers around your front door or back porch.

Hydrangeas have the additional benefit of bridging a gap in the gardening calendar.  When spring bulbs fade and summer annuals decline, hydrangeas bloom and produce flower heads that last from mid-summer until the first fall frost, which is around October 17 for Allentown, Pennsylvania.

Types of Hydrangeas

To ensure that you’re successful at growing hydrangeas, you need to know the main hydrangea types so you can choose the best hydrangea for your garden.

Bigleaf Hydrangeas

Bigleaf hydrangeas are classic varieties that produce mophead or lacecap flower clusters.  Their flower buds grow on stems grown during the previous year (a.k.a. “old wood”), so the flowers require protection during Pennsylvania’s cold temperatures in the winter and early spring to protect early spring buds.

Limelight Hydrangeas (Panicle Hydrangeas)

Limelight hydrangeas are a type of panicle hydrangea, which is a tough and easy-to-grow hydrangea variety that is cold-tolerant. They have large, cone-shaped flower clusters that only grow on new wood (meaning the current growing season’s stems).  The flowers begin as white or lime green before maturing to pink in the fall. 

Smooth Hydrangeas

The smooth hydrangea is a native plant to Pennsylvania. Some varieties grow white, snowball-esque blooms that work well for woodland garden designs and cottage gardens. Like panicles, smooth hydrangeas bloom on new wood, so freezing winters will not compromise the flowers that will bloom in the summer.

Oakleaf Hydrangeas

Known for its oak-shaped leaves and flower cones, oakleaf hydrangea shrubs offer year-round interest and year-round color, particularly since their foliage turns bronze, crimson, and purple in the fall.  Oakleaf hydrangeas tolerate more shade than other types of hydrangeas, so they are great shade garden plants.

How to Care for Hydrangeas

To get beautiful blooms from your hydrangeas, make sure that you achieve the proper balance of water and nutrients, and you need to prune the plants appropriately.

Watering

Hydrangeas need consistent watering, especially during dry stretches in July and August. Water at the base of the plant and avoid spraying foliage to help prevent fungal diseases. Give your hydrangea about one inch of water per week for established plants and increase the watering frequency for newly-planted shrubs. 

If you have any questions about watering your hydrangeas, give our Allentown, Pennsylvania garden center a call at 610-391-1570 and we’ll be happy to guide you.

Soil & Mulching

Hydrangeas need moist, fertile, and well-draining soil. To help the soil retain moisture and shield the plant’s root systems from Pennsylvania’s summer heat, apply a two-to-three-inch layer of organic mulch around the base of the plant.

Pruning

Pruning depends on the type of hydrangea you grow. For panicle (including Limelight) and smooth varieties (which bloom on new wood), prune the plant back in late winter or early spring to encourage fresh flowering stems.

For bigleaf and oakleaf varieties (which bloom on old wood), avoid winter pruning.  Trim them immediately after they finish blooming in summer so you don’t cut off next year's flowers.

Where to Plant Hydrangeas

Location matters when establishing hydrangeas because some thrive in the sun and some do best in the shade.  So, matching the hydrangea variety to your yard's light levels helps your plant grow and produce its best blooms.

For Shady Spots

Use oakleaf and smooth hydrangeas for the north side of a home or under tree canopies since these plants grow well in the shade.  However, they maximize their blooms when they get filtered morning light.

For Spots with Morning Sun and Afternoon Shade

Bigleaf hydrangeas thrive in spots with morning sun and afternoon shade.  This is because morning light fuels bud production while afternoon shade protects the leaves from wilting under the midday sun.

For Sunny Spots

Plant Limelight hydrangeas and other panicle hydrangeas in spots that have sunlight for six or more hours a day.  Panicle hydrangeas need direct light to produce sturdy stems and vibrant color transitions.

How to Change Hydrangeas’ Color

You can control what color your bigleaf hydrangea’s flowers are.  But how do you change your hydrangea’s color? 

It all comes down to the soil’s pH. The soil’s pH dictates how much aluminum the plant absorbs, and it’s the aluminum that alters the flowers’ colors. 

For blue booms, give your plant an acidic soil (a pH of 5.5 or lower).  You can lower the soil’s pH by adding a soil acidifier or aluminum sulfate to the dirt around your hydrangea.  You can also give your hydrangea an acidic fertilizer.

For pink blooms, give your hydrangea an alkaline or neutral soil (a pH of 6.5 or higher).  Add garden lime to raise the soil’s pH.

Whatever soil amendment you choose, it must be gradual to avoid shocking the plant.  Also, know that only the bigleaf hydrangea variety allows you to alter the flowers’ color in this way.  For further guidance and for these gardening supplies, visit our garden center in Allentown, Pennsylvania.

Get Hydrangeas at Lehigh Valley Home and Garden Center

Hydrangeas are one of the top-selling shrubs in America, and we have a variety of healthy hydrangeas at Lehigh Valley Home and Garden Center.  Our hydrangeas are suited to handle Pennsylvania’s climate, temperature fluctuations, and soil profiles.  Plus, our plant experts and friendly staff can give you advice on placement, pruning, soil preparation, and hydrangea care.

If you save plant videos on TikTok or Instagram, bring your phone during your next visit. Show us your video, and our team will help you identify those varieties and find matches to recreate that look in your garden.  Stop by our Allentown garden center to get started.