The ‘Blue Deckle’ Hydrangea is a captivating choice for gardens, offering an elegant display of color and form. Its unique blooms and manageable size make it a desirable plant for various landscape designs, appreciated for its subtle charm and consistent seasonal color.
Understanding Blue Deckle Hydrangeas
‘Blue Deckle’ Hydrangea (Hydrangea serrata ‘Blue Deckle’ or Hydrangea macrophylla ‘Blue Deckle’) is a distinctive lacecap variety. It features large heads of tiny “true” flowers encircled by a ring of larger, showy florets. The term “deckle” refers to the finely serrated or fringed edges of these outer sepals, contributing to its delicate and textured appearance. This compact, rounded deciduous shrub typically reaches about 3 to 4 feet tall and wide.
The natural coloration of ‘Blue Deckle’ blooms ranges from pale pink to lavender in neutral soil. In acidic soil conditions, its signature pale blue hue emerges. The foliage is dark green and glossy with pointed tips, often developing attractive red or purple hues in autumn, adding seasonal interest.
Planting and General Care
Choosing a Location
‘Blue Deckle’ Hydrangeas thrive in partial shade, ideally receiving morning sun and protection from intense afternoon heat. While they can tolerate some full sun in cooler climates, direct sun can burn the flowers. A sheltered location also protects the plant from strong winds.
Soil Preparation
‘Blue Deckle’ Hydrangeas perform best in moist, fertile, and well-drained soil. Proper drainage prevents waterlogging and root issues. Incorporating organic matter, such as compost or well-rotted bark, improves fertility and structure. Plant at the same level as the container, in a hole twice the root ball’s diameter.
Watering
Consistent moisture is necessary for ‘Blue Deckle’ Hydrangeas, especially during establishment and dry spells. While they appreciate moist conditions, avoid overwatering to prevent root rot. Container plants may require more frequent watering, sometimes twice daily during hot summer months. Monitor soil moisture regularly.
Fertilizing
‘Blue Deckle’ Hydrangeas benefit from regular feeding for robust growth. Apply a slow-release fertilizer at planting. In early spring, as new growth begins, use an organic-based fertilizer like blood and bone meal, or a balanced shrub fertilizer.
Pruning and Winter Protection
Pruning Techniques
‘Blue Deckle’ Hydrangeas bloom on old wood, meaning flower buds form on previous year’s growth. Prune after flowering, typically in late summer or early autumn. Alternatively, prune in early spring after the danger of frost, as spent flowers and leaves offer some protection. Remove flowered canes, thin, crowded, or damaged shoots, cutting them back to the base. Leave unpruned shoots, as these will produce next season’s blooms. Deadheading spent flowers can encourage further blooming and improve appearance.
Winterizing Your Hydrangea
‘Blue Deckle’ Hydrangeas are hardy in USDA Zones 5 through 10a. In zones colder than 7, provide winter protection to safeguard latent flower buds. Apply a generous layer of mulch, such as pine needles, pine bark, or leaf litter, around the base in late autumn. This insulates roots, retains soil moisture, and helps protect lower buds.
Keeping Your Hydrangea Blue
The Science of Blue
The blue color of ‘Blue Deckle’ Hydrangea flowers is directly influenced by aluminum availability in the soil. For absorption, the soil must be acidic, ideally pH 5.2-5.5. In this acidic environment, aluminum ions become soluble and accessible, interacting with anthocyanin pigments to create blue coloration. In alkaline conditions, aluminum is less available, leading to pinker blooms. Using a low-phosphorus fertilizer is recommended, as phosphorus can bind with aluminum.
Adjusting Soil pH
To encourage blue blooms, lower the soil pH. Elemental sulfur is effective for acidifying the soil. Peat moss can also reduce pH over time. Coffee grounds may provide a slight, temporary pH reduction. Soil adjustments are not instantaneous and may take several months to a year. Test soil regularly to monitor pH levels.
Aluminum Sulfate Application
Applying aluminum sulfate directly provides aluminum and lowers soil pH for blue blooms. Dissolve about 1 tablespoon of aluminum sulfate per gallon of water and apply as a soil drench around the root zone. Apply in early spring (March, April, May) before flower buds fully develop. For ongoing maintenance, repeat applications every few weeks or 6-8 weeks, depending on soil conditions. Water the plant thoroughly before applying aluminum sulfate to prevent root burn. Avoid getting the solution on the leaves.