How to Grow and Care for Annabelle Hydrangea

Annabelle hydrangea earns its reputation as one of the best-loved, smooth-leaf hydrangeas because it is covered all summer in huge, rounded flowers measuring up to a foot across. Large, crisp white blooms make a statement against a background of dark green, sharply toothed foliage. Annabelle hydrangea is a low-maintenance cultivar that prefers acidic, moist clay or rocky soil and thrives in full or partial sun and moderate temperatures. This shrub is also tolerant of the black walnut tree. All hydrangeas are toxic to animals.

Annabelle Hydrangea Care

Here are the main care requirements for growing Annabelle hydrangea.

• Plant Annabelle hydrangea where there's morning sun and afternoon shade.
• Keep soil on the acidic side and consistently moist but not soggy for this plant.
• Fertilize an Annabelle hydrangea once a year.

Light

Plant Annabelle hydrangea where it receives morning sun and afternoon shade. The shrub tolerates full sun only in locations that are consistently moist. It can survive in full shade, though blooms may be diminished without some sun exposure.

Soil

Soil acidity does not impact the color of an Annabelle hydrangea's white flowers. The plant adapts to soil composition from clay to sandy with pH levels of 5.5 to 6.5 (acidic).

Water

Annabelle hydrangea is not drought tolerant, so it must be watered regularly throughout the growing season to keep soil consistently moist. The leaves and flowers decline in hot, dry conditions. In southern regions you may have to water as much as three times a week.

Temperature and Humidity

Temperatures between 65 and 85 degrees Fahrenheit provide the ideal environment for an Annabelle hydrangea. Flowers fade quickly in heat levels above 85 degrees Fahrenheit. The shrub tolerates winter temperatures down to 30 degrees Fahrenheit. For best flowering, it needs a six- to eight-week period of temperatures around 40 degrees Fahrenheit.

Fertilizer

Fertilize Annabelle hydrangea annually in early summer with a slow-release, organic, acidic fertilizer with an NPK of 15-10-10 or 10-5-5. Alternatively, treat the leaves with kelp or fish emulsion foliar spray.

Pruning Annabelle Hydrangea

This cultivar blooms on new wood, which means the only time you should not prune the Annabelle hydrangea is when new spring growth emerges.

In autumn, you can remove the flowers, which have faded to tan, or leave them on for winter interest. They should be removed in late winter, along with any diseased or damaged branching. Annabelle hydrangea can also be cut to ground level in winter or when the growing season ends. Leave several old-growth branches to support new growth and the large, heavy flowerheads.

Propagating Annabelle Hydrangea

Annabelle hydrangea is propagated with softwood cuttings taken in the spring. You'll need 3- to 5-inch pots with drainage holes, sandy potting mix, rooting hormone, and sterile clippers. Here is how to increase your hydrangea collection.

1. Fill several small pots or a larger pot with loose, sandy potting mix. Several cuttings can be rooted in one larger pot.
2. Clip 6 to 12 inches of a new branch that has five or six softwood stems and leaves.
3. Separate softwood stems from the main branch and remove lower leaves from these cuttings.
4. Dip the bottom of each cutting in rooting hormone to cover the nodes where the bottom leaves were removed.
5. Make deep, narrow holes in the potting mix and insert the bottoms of the cuttings into the holes. Three to four cuttings can be placed in a 5-inch pot.
6. Water and continue to keep the soil moist.
7. Place in a shaded area with filtered or indirect light. Roots form in two to three weeks.
8. Pot up individual seedlings into their own 3- to 5-inch containers and grow out until fall when new shrubs can be transplanted into the garden.

Overwintering

Because Annabelle hydrangea blooms on new growth, only its roots need protection from winter temperatures that dip below 30 degrees Fahrenheit. Maintain a 3-inch layer of wood chips or pine straw and add more in the fall if needed. Mulch will also help retain soil moisture.

Common Pest and Plant Diseases

This smooth hydrangea is vulnerable to the larval form of the leaftier moth, which cocoons in leaves and can cause diminished flowering. When you find distorted foliage or leaves stuck together, this small, black-headed caterpillar is likely responsible. Organic pesticide BTK is effective as a preventive if applied on new leaves in the spring. If caterpillars have established cocoons, remove and dispose of the leaves and any damaged flower buds.

Leaf spot, powdery mildew, and rust aren't common but these fungal infections can affect Annabelle hydrangea. Manage these issues with proper moisture and sunlight exposure. In severe cases, spray foliage with the recommended fungicide.

How to Get Annabelle Hydrangea to Bloom

Bloom Months

Annabelle hydrangea first blooms in June as small green corymbs (flower clusters) that open to white as they increase in size. Blooming continues through August with a brief re-blooming phase in autumn.

What Do Annabelle Hydrangea's Flowers Look and Smell Like?

Annabelle hydrangea has colossal 12-inch clusters of dozens of small white flowers that cover the shrub in prolific numbers. Flower heads are uniform and rounded, resembling large snowballs. Buds are green but turn white when fully open and hold color until autumn when they fade to tan. Annabelle hydrangea's flowers do not have a scent.

How to Encourage More Blooms

If Annabelle hydrangeas are getting enough water and light, they should bloom effortlessly. However, removing faded flowers plus an inch of stem growthmay stimulate the hydrangea into a second flush of blooms.

Common Problems With Annabelle Hydrangea

This smooth hydrangea cultivar is relatively problem-free. Regular watering to keep soil consistently moist, planting in well-draining soil, and pruning back to ground level in autumn work to avoid fungal infections that plague other ornamental shrubs. But watch for signs that your Annabelle hydrangea may be in distress so you can return it to health.

Plant is Drooping

A drooping Annabelle hydrangea may need water. Annabelle hydrangeas are not drought tolerant and require regular watering to keep the soil consistently moist. The plant may be receiving too much sun which may make the hydrangea droop, as well.

No Blooms

Annabelle hydrangeas need sufficient water and light to develop buds to bloom. The plant may have been pruned too late in the seasons, as well, reducing the number of buds that set on the new wood.

Leaves Turning Brown

Your Annabelle hydrangea may be suffering from scorch. Scorch occurs from dry winds, extreme sunlight, or underwatering.

Leaves Turning Yellow

Hydrangea leaves turn yellow for many reasons. Yellow leaves happen because of too much or too little hydration, poor soil, pests, or a lack of nutrients, Learn the cause and mediate your plant's conditions to improve its health.

From: thespruce