How To Choose and Plant Hydrangeas

Hydrangeas are beloved for their stunning, showy blooms that add a touch of elegance to any garden. These versatile shrubs come in various colors and sizes, making them a popular choice for both novice and experienced gardeners. In this guide, we’ll explore how to select the right hydrangea for your landscape and hardiness zone and provide step-by-step instructions for planting these beautiful flowers. This Old House landscaping contractor Roger Cook shares his expertise on choosing and planting hydrangeas in the video above.

*Unless otherwise noted, costs in this article reflect an average of prices that our team found from hardware stores like Lowes and Home Depot, and on Amazon.com.

Selecting the Right Hydrangea

When it comes to choosing a hydrangea, there are several factors to consider. Making the right choice from among the various species available to your specific garden conditions will ensure your hydrangeas thrive.

Types of Hydrangeas

There are several popular types of hydrangeas, each with its own unique characteristics:

• Bigleaf hydrangeas (Hydrangea macrophylla): Known for their large, colorful blooms that can change color based on soil pH
• Oakleaf hydrangeas (Hydrangea quercifolia): Native to North America, featuring distinctive oak-like leaves and white flowers
• Panicle hydrangeas (Hydrangea paniculata): Hardy plants with cone-shaped flowers that bloom late in the season
• Smooth hydrangeas (Hydrangea arborescens): Known for their large, round flower heads and ability to tolerate more sun

Considering Your Garden Conditions

Before selecting a hydrangea, assess your garden’s conditions to ensure the plant will thrive:

• Available space: Consider the mature size of the plant when selecting a location
• Climate: Choose a variety that is suitable for your USDA Hardiness Zone
• Soil type: Hydrangeas generally prefer well-draining, rich soil
• Sunlight: Most hydrangeas prefer partial shade, but some varieties can tolerate more sun

Planting Your Hydrangea

Once you’ve chosen the perfect hydrangea for your garden, it’s time to plant. Follow these steps to ensure your new shrub gets off to a great start.

Timing Your Planting

The best time to plant hydrangeas is in the spring or fall when temperatures are mild. This allows the plant to establish its root system before facing extreme weather conditions. Roger Cook demonstrates planting a hydrangea in early fall, which is an ideal time.

Preparing the Planting Site

Proper site preparation supports the success of your hydrangea. To begin, choose a location with the proper amount of sunlight for your specific variety. Next, clear the area of weeds and grass. Dig a hole twice as wide as the root ball and just as deep. Finally, amend the soil with compost to improve drainage and fertility.

Planting Process

Follow these steps to plant your hydrangea:

1. Remove the plant from its container and gently loosen the roots by gently scratching the sides with a cultivator.
2. Place the plant in the hole and make sure it’s about the same depth as it was in the container.
3. Backfill the hole with the amended soil, firming it gently around the roots.
4. Water thoroughly to settle the soil and eliminate air pockets.

Watering and Mulching

Post-planting care helps the plant’s health. Water deeply and regularly, especially during the first growing season. Apply a 2–3-inch layer of organic mulch around the base of the plant, keeping it away from the stem. Watch soil moisture and adjust watering as needed.

Pro Tip: Hydrangeas are heavy drinkers. According to This Old House Magazine, those planted in sandy, fast-draining soils or beneath water-hogging shade trees are especially prone to drying out in summer. During the growing season, regularly check the top 6 inches of soil for moisture to ensure your hydrangeas stay hydrated.

Additional Planting Tips

Apart from the essentials, there are additional tips to enhance your hydrangea’s growth:

• Spacing: Provide adequate spacing between plants to allow for proper air circulation
• Companion plants: Plant hydrangeas alongside other shade-loving plants like ferns and hostas
• Monitoring growth: Regularly check for signs of stress or disease and address them promptly

Caring for Your Hydrangea

Proper care will ensure your hydrangea thrives and produces abundant blooms year after year.

Pruning

Pruning requirements vary depending on the type of hydrangea:

• Bigleaf and oakleaf hydrangeas: Prune after flowering in late summer
• Panicle and smooth hydrangeas: Prune in late winter or early spring before new growth begins

Fertilizing

Feed your hydrangea with a balanced, slow-release fertilizer in spring as new growth emerges. Avoid over-fertilizing, as this can lead to lush foliage at the expense of flowers.

According to This Old House Magazine, you should sprinkle just a half cup of slow-release 10-10-10 granular plant food around the shrub’s entire root zone in early spring, then apply a second dose in midsummer. Hydrangeas also benefit from an annual topdressing of well-rotted manure or compost, which supplies nutrients and improves the soil’s moisture retention.

Winter Protection

In colder regions, protect your hydrangeas from winter damage. Start by applying a thick layer of mulch around the base of the plant. For severe winter conditions, wrap the shrub in burlap. If you have potted hydrangeas, move them to a protected area or bury the pot in the ground.

Pro Tip: Susan Cohan, a landscape designer featured in This Old House Magazine, advises: “The safest approach is to move the container into an unheated garage and water the soil periodically during the winter. Put it back outside in early spring when the danger of a deep freeze is past.” If you prefer to leave pots outdoors, she recommends placing them in a spot sheltered from wind and out of the sun, and insulating the soil by piling leaf mulch around the outside of the container and holding it in place with burlap.

Handling Pests and Diseases

Even with proper care, hydrangeas can sometimes face challenges from pests and diseases. Here are a few to watch for:

• Aphids: These small insects can cluster on new growth. Treat them with insecticidal soap.
• Powdery mildew: A common fungal issue that appears as a white powder on leaves. Ensure good air circulation and avoid overhead watering to prevent this.

Troubleshooting Common Hydrangea Issues

Even with meticulous care, hydrangeas can sometimes face challenges. Here are some common issues and how to address them:

Lack of Blooms

If your hydrangea isn’t blooming, consider these potential causes:

• Improper pruning: Ensure you’re pruning at the right time for your specific variety
• Insufficient sunlight: Move the plant to a sunnier location if necessary
• Late spring frost: Protect buds from frost damage in early spring
• Wrong variety for Hardiness Zone: Your hydrangea may be a species that isn’t suited for your Hardiness Zone, like the example in the video. 

Leaf Problems

Hydrangea leaves can sometimes develop issues:

• Brown spots: Indicate a fungal disease—improve air circulation and avoid overhead watering
• Wilting: Often caused by under-watering or excessive heat, so adjust watering accordingly
• Yellowing leaves: This may indicate nutrient deficiency or overwatering

Understanding Yellow Leaves: If only new foliage is yellowing, the plant may need more iron—a condition called chlorosis that often occurs where soils have a high pH. Amending the soil with chelated iron and mixing in some compost will correct the issue. If only older leaves are yellowing, however, try fertilizing, as the shrub may be lacking essential nutrients.

Enhancing Hydrangea Blooms

Apart from regular care, a few additional tips can help enhance the blooms of your hydrangea.

Adjusting Soil pH

For bigleaf hydrangeas, bloom color can be influenced by soil pH. Acidic soils (pH below 6) result in blue flowers, while alkaline soils (pH above 7) lead to pink flowers. Test your soil pH and amend it accordingly using aluminum sulfate to lower pH—like Roger demonstrates in the video—or lime to raise it.

Why It Works: Hydrangeas require aluminum to produce blue flowers. Plants can easily extract metals from acidic soils, but under alkaline conditions, metals become insoluble and flowers bloom pink. This is why simply adjusting pH — rather than adding dye or other additives — is the most effective way to shift bloom color.

Providing Adequate Nutrients

In addition to regular fertilizing, providing hydrangeas with additional nutrients can enhance blooms. Use a mix rich in phosphorus. Organic options like bone meal and compost can be beneficial as well.

Optimal Watering Techniques

Hydrangeas benefit from consistent and deep watering. Consider using a drip irrigation system to ensure plants receive a steady supply of moisture without overdoing it.

Creative Landscaping with Hydrangeas

Hydrangeas can be more than just additions to your garden—they can be centerpieces. Here are some creative landscaping ideas:

Designing Hydrangea Borders

Use hydrangeas to create stunning borders along pathways or garden edges. Their lush blooms add color and texture. Pair them with evergreen shrubs to maintain visual interest year-round.

Mixing Varieties

Incorporate different types of hydrangeas for diverse textures and bloom times. For example, mix bigleaf and panicle hydrangeas for a prolonged blooming season.

Creating Focal Points

Plant hydrangeas in strategic locations to serve as eye-catching focal points in your garden. Use them around seating areas, near entryways, or as part of larger flower beds.

Our Conclusion

Choosing and planting hydrangeas can be incredibly rewarding for any gardener. By selecting the right variety for your local climate, providing proper planting and care techniques, and employing additional tips for enhancing blooms, you can enjoy these stunning shrubs for years‌ to come. Remember to be attentive to factors like sunlight, soil type, and climate when making your selection. Don’t hesitate to experiment with different varieties to find your perfect hydrangea. 

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