Hydrangea Care Guide: How To Grow and Care for Hydrangeas
If you are looking for a flowering shrub for your landscaping that is beautiful, resilient, and adaptable, then look no further than the hydrangea! From their large and showy blooms to their deep green foliage, these landscaping plants are perfect for growing in a number of different Colorado environments and are one of the few flowering shrubs that grow well in shaded conditions. Hydrangeas come in a number of varieties all with their own unique features and growing requirements. Learn more about hydrangeas and find the perfect one for your yard today!
What Are Hydrangeas?
Hydrangeas are a popular ornamental flowering shrub belonging to the genus Hydrangea. They are known for their large, showy flower clusters and are widely cultivated for their attractive blooms and lush foliage. Hydrangeas are native to various regions in Asia and the Americas, and there are numerous species and cultivars available. Hydrangeas are often used in gardens, landscapes, and floral arrangements due to their striking appearance. They prefer moist, well-draining soil and typically thrive in partial shade to filtered sunlight, though some varieties can handle full sun. Proper care and maintenance, including regular pruning and adequate watering, can help keep hydrangeas healthy and vibrant.
The most distinctive feature of hydrangeas is their flower clusters, which are large and often globe-shaped or dome-like. These clusters can be several inches in diameter and are made up of smaller individual flowers. One unique aspect of hydrangeas is their ability to change flower color based on soil pH. In acidic soils (lower pH), they tend to produce blue or purple flowers, while in alkaline soils (higher pH), they produce pink or red flowers (learn how to change soil pH below). White and green varieties are also common, and some cultivars maintain their color regardless of soil pH. Hydrangea leaves are typically large and glossy with serrated edges, creating an attractive and contrasting backdrop for the flowers.
Hydrangeas vary in size and growth habits. Some are compact and suitable for containers or smaller garden spaces, while others can grow into large, mounding shrubs. The blooming season for hydrangeas varies depending on the species and cultivar. Some varieties bloom in early summer, while others flower in late summer or early autumn.
Types Of Hydrangeas
There are numerous hydrangea cultivars available, each with their own unique flower shape, color, and growth habits. Some popular cultivars include the following:
Hydrangea macrophylla (Bigleaf Hydrangea)
If you are looking for the type of hydrangea whose flower color changes depending on the pH of the soil, this is the one! Bigleaf hydrangeas can display a flower color that is either pink or a blue-purple color based on the acidity or alkalinity of the soil. They generally bloom in late spring and push sequential blooms through summer. They make for wonderful cut flowers and can reach 3-5 feet tall and 4-5 feet wide once mature. Macrophylla hydrangeas have big glossy leaves that contrast beautifully with the flowers.
Hydrangea paniculata (Panicle Hydrangea)
Panicle hydrangeas are the easiest to grow, being very hardy and adaptable to a number of different environments. They are drought tolerant, can handle more sun exposure than other hydrangea varieties, and can even grow in poor soils as long as there is good drainage. The flower color of panicle hydrangeas is less affected by soil pH and are more affected by the season. Panicle hydrangeas bloom in mid-to-late summer and hold their blooms through fall. Blooms are white or lime in the summer and often transition to a pink/mauve color in the fall. Their leaves are more leathery than other types of hydrangeas and have better heat tolerance once established.
Hydrangea arborescens (Smooth Hydrangea)
Hydrangea arborescens, often referred to as smooth hydrangea or wild hydrangea, are easy to grow and can adapt to a number of different soil conditions, though they are not tolerant of drought and prefer to be grown in medium, consistent moisture. Well-draining soil will also be important, and slightly shaded conditions are ideal. The Annabell hydrangea is possibly one of the most popular varieties, displaying breathtaking clusters of white flowers up to 12 inches across!
Hydrangea quercifolia (Oakleaf Hydrangea)
As can be assumed by the name, Oakleaf hydrangea differs from other varieties in the shape of their foliage, which resemble oak leaves. The blooms on this flowering shrub also appear in cone-shaped clusters of either single or double blooms that appear in late spring and last through early summer. This versatile shrub is tolerant of a variety of different growing conditions and displays beautifully colored foliage throughout the fall, resembling a tie-dye effect of purples, reds, and oranges.
How To Care for Hydrangeas
Caring for hydrangeas involves providing the right growing conditions, proper watering, pruning, and occasional fertilization. Here are some essential tips for caring for hydrangeas:
1. Hydrangea Soil Requirements
Ensure the soil is well-draining and rich in organic matter. Hydrangeas thrive in slightly acidic to neutral soil (pH 5.5 to 7). If you want blue flowers, keep the soil acidic (pH below 6.0). You can amend the soil with Soil Acidifier to change the pH in this way. For pink flowers, make the soil slightly alkaline (pH above 6.0). To achieve this, amend your soil with Garden Lime.
2. Hydrangea Watering Needs
Hydrangeas require regular watering, especially during dry spells and intense summer heat. Keep the soil consistently moist but not waterlogged. A deep watering once or twice a week is generally sufficient for established shrubs, depending on your climate and soil type.
3. Hydrangea Sun Requirements
Hydrangeas grow well in shaded or partially shaded conditions, preferring locations with morning sun and afternoon shade. Be careful, excessive heat and direct sunlight can stress the plants and affect flower production.
4. Fertilizing Your Hydrangeas
Hydrangeas benefit from a balanced fertilizer formulated for flowering shrubs. Apply it in spring, following the manufacturer's instructions. Avoid excessive use of high-nitrogen fertilizers, as this can lead to lush foliage but fewer flowers.
5. How to Prune a Hydrangea
The pruning requirements depend on the hydrangea type:
Bigleaf Hydrangeas (Hydrangea macrophylla): Prune after flowering, removing dead or weak wood and cutting back old flower heads to a healthy pair of buds.
Panicle Hydrangeas (Hydrangea paniculata): Prune in late winter or early spring before new growth begins. Prune back dead wood only. Panicle hydrangeas can also be pruned for size control and to improve airflow between limbs.
Oakleaf Hydrangeas (Hydrangea quercifolia): Minimal pruning is required. If necessary, prune after flowering.
Smooth Hydrangea (Hydrangea arborescens): Blooms form on new wood, so plants may be pruned back close to the ground in late winter. This will revitalize the plant and encourage vigorous stem growth and best form.
6. Pest and Disease Control
Keep an eye out for common pests like aphids, mites, and snails. If necessary, use environmentally friendly methods or insecticidal soaps to control them. Hydrangeas can be susceptible to diseases like powdery mildew and leaf spot, so ensure good air circulation and avoid overhead watering. Copper fungicide is what we recommend for use in the case of most diseases your plant may encounter.
7. Winter Protection
In colder climates, protect the plant during the winter by adding extra mulch around the base and covering the plant with burlap or a frost blanket. This is only necessary during extremely cold temperatures or dramatic fluctuations in winter temperatures. Cold hardiness can vary depending on the hydrangea variety.
Removing spent flowers can encourage the plant to produce more blooms. However, for certain varieties, leaving the faded flowers on the plant can add winter interest and protect new buds from frost damage.
Remember that different hydrangea varieties may have specific care requirements, so it's essential to identify the type of hydrangea you have and tailor your care accordingly. With proper attention, hydrangeas can reward you with beautiful, long-lasting blooms year after year. If you need help identifying your hydrangea and its specific care needs, come into the Garden Center or reach out to us to get in touch with one of our plant professionals!
How To Plant Hydrangeas
1. Choose the Right Location
Ensure that the area you are planting in is suited to the needs of the specific type of hydrangea you choose to plant. Take into consideration which side of your house you plant on. North-facing areas get the least sun and South-facing areas get the most sun. Consider things like proximity to your home or other structures, other plants in the area, trees that may create dense shade, and the like.
2. Prepare Your Soil and Dig Your Hole
It is always a good idea to test the pH of your soil before planting any new tree, shrub, or perennial. Most hydrangeas prefer slightly acidic to neutral soil (pH 5.5 to 7). Amend the soil to achieve the ideal soil pH. Adding organic matter such as compost or well-rotted manure is also recommended to improve drainage and enrich the soil. Dig a hole that is two to three times the width of the root ball and slightly shallower than the height of the root ball. If you're planting multiple hydrangeas, be sure to space them adequately so they do not crowd each other when they reach mature size.
3. Plant Your Hydrangea
Gently remove the hydrangea from its nursery container, being careful not to damage the roots. You may have to score the root ball if you notice the plant has become rootbound (roots appear to be circling inside the pot). Place the plant in the center of the hole and backfill with the soil you removed. Gently press the soil down around the root ball to remove any air pockets.
4. Water Your Newly Planted Hydrangea
After planting, water the hydrangea thoroughly to settle the soil and help the plant establish its root system. During the first few weeks, check the soil moisture regularly and keep it consistently moist, but not waterlogged. Consistent watering within the first year of growth will be important to help your hydrangea establish a strong and deep root system. Remember that slow and deep watering is always better than fast and shallow watering!
5. Mulch Around Your Plant
Apply a layer of mulch around the base of the plant to help retain moisture, regulate soil temperature, and suppress weed growth. Avoid piling the mulch against the main stem, as it can lead to rot.
Hydrangea Propagation Tips
Hydrangeas are beautiful flowering shrubs that can be propagated through various methods, including cuttings, layering, and division. Here are some tips for successfully propagating hydrangeas:
1. Choosing the Right Time
The best time to propagate hydrangeas depends on the method you're using. Generally, late spring to early summer is a good time for softwood cuttings, while late fall to early winter is suitable for hardwood cuttings and division.
2. Taking Softwood Cuttings
Select healthy, non-flowering stems with new growth that's not too woody.
Cut a 4-6 inch section just below a leaf node.
Remove the lower leaves, leaving only a few at the top.
Dip the cut end in rooting hormone (optional but can improve success).
Plant the cutting in a well-draining potting mix or a mix of peat and perlite.
Cover the cutting with a plastic bag or a clear plastic dome to create a humid environment.
Place the container in a bright, indirect light location.
Keep the soil consistently moist but not waterlogged.
Once the cutting has rooted and shows signs of new growth, you can transplant it into a larger pot or directly into the garden.
3. Taking Hardwood Cuttings
Collect 6-12 inch sections of mature, woody stems during the dormant season.
Make a slanting cut just below a leaf node at the base and a straight cut just above a node at the top.
Dip the bottom end in rooting hormone.
Plant the cuttings in a container filled with a well-draining rooting medium.
Water the cuttings and place the container in a sheltered spot with indirect light.
Keep the medium consistently damp but not waterlogged.
Over the winter, protect the cuttings from extreme cold and provide occasional misting to maintain humidity.
In spring, when the cuttings have rooted and new growth appears, they can be transplanted.
Choose a flexible, low-growing branch on the hydrangea.
Bend the selected branch down to the ground.
Make a small wound on the underside of the branch where it touches the soil.
Apply a rooting hormone to the wounded area.
Secure the branch in place using a U-shaped pin or a small rock.
Cover the wounded area with soil and keep it consistently moist.
In a few months, roots should form where the branch touches the soil.
Once roots are established, cut the new plant from the parent plant and transplant it.
Dig up an established hydrangea plant during its dormant period.
Use a sharp, clean tool to divide the plant into smaller sections, ensuring that each section has roots and healthy growth.
Replant the divided sections in new locations or containers.
Water the divisions well and provide appropriate care as they establish themselves.
Remember that not all hydrangea varieties respond equally to all propagation methods. It's a good idea to research the specific hydrangea variety you have and follow propagation guidelines tailored to that particular type. Patience and attention to detail are key to successfully propagating hydrangeas.
Common Hydrangea Problems & Solutions
Hydrangeas are popular and beautiful flowering shrubs, but like any plant, they can face various issues. Here are some common hydrangea problems and their potential solutions:
1. Improper Flowering
Issue: Hydrangeas may not flower if they're not receiving enough sunlight or if they've been pruned at the wrong time.
Solution: Ensure your hydrangea gets the recommended amount of sunlight for its specific variety. If you need to prune, do so immediately after flowering to avoid removing next year's flower buds.
2. Leaf Spots
Issue: Fungal diseases, such as leaf spot, can cause dark spots on hydrangea leaves.
Solution: Prune affected leaves, improve air circulation around the plant, and avoid overhead watering. Applying fungicides as a preventive measure can also help.
3. Powdery Mildew
Issue: Powdery mildew appears as a white, powdery substance on leaves and stems.
Solution: Choose mildew-resistant varieties and maintain proper spacing to ensure good air circulation. Apply fungicides as necessary, and avoid overhead watering.
4. Wilting Leaves
Issue: Hydrangeas may experience wilting leaves, which could be due to insufficient watering, root rot, or poor drainage.
Solution: Ensure the plant is receiving adequate water, especially during dry periods. Improve drainage if necessary and avoid overwatering.
5. Insect Infestations
Issue: Insects like aphids, spider mites, and Japanese beetles can damage hydrangeas.
Solution: Regularly inspect your plants for signs of infestation and use insecticidal soaps, neem oil, or other appropriate insecticides to manage the pests.
7. Yellowing Leaves
Issue: Yellowing leaves can be caused by nutrient deficiencies, poor soil drainage, or overwatering.
Solution: Test the soil to identify nutrient deficiencies and amend as necessary. Ensure proper drainage and adjust watering practices.
8. Stunted Growth
Issue: Stunted growth can result from poor soil quality, improper planting, root damage, or drought stress.
Solution: Plant hydrangeas in well-draining soil enriched with organic matter. Ensure proper planting depth and spacing, and avoid damaging roots.
9. Winter Damage
Issue: Harsh winter conditions can cause damage to hydrangeas, including dieback.
Solution: Protect plants from extreme cold by applying a layer of mulch around the base and covering the plant with burlap or other protective materials.
10. Nutrient Deficiencies
Issue: Hydrangeas may show signs of nutrient deficiencies, such as yellowing leaves on old growth, yellowing leaves with green veins, dwarfed leaf growth, or forfeiting blooms.
Solution: Fertilize your hydrangeas according to their specific needs. Acid-loving varieties may benefit from an acidifying fertilizer, while other types may require a balanced fertilizer.
Get Help From the Professionals
We hope you have found this information helpful as you learn to plant and grow hydrangeas in your landscaping and flowerbeds! If you have questions, please feel free to reach out or come into the Garden Center. Our nursery professionals are more than willing to help answer any of your questions. You can also view different types of hydrangeas in our Plant Finder and shop tons of varieties in-store today!