The beauty of a hydrangea macrophylla (Mathilda Gutges) lies in its crowded balls of flat-leaf blossoms, which appear in shades of pink, blue or purple, depending on the acidity level of the soil. Introduced in Germany in the mid-1950s, Mathilda Gutges hydrangeas grow from 3 to 6 feet tall, bloom from midsummer to fall and tolerate light frost. Whether propagated by seed or cutting, these prolific shrubs provide interest to flower gardens and landscapes for many years.
Place enough large stones or pieces of broken pottery at the bottom of the container to keep the soil in the pot while allowing water to pass through the drainage hole at the bottom.
Fill the container with equal parts slightly moistened potting soil, organic compost and coarse sand to create a loamy, well-draining base for the hydrangea.
Dig a hole deep enough to accommodate the root ball of the starter plant while allowing the top of the root ball to sit level with the soil line.
Remove the starter plant from the store-bought container and gently loosen any compacted roots, using your fingers to lift roots away from the soil without tearing them.
Place the plant into the prepared hole and pack soil around the sides to keep it in an upright position.
Moisten the plant thoroughly with water to set it in place and cover it up to the stem with a 3- to 5-inch layer of mulch or organic compost.
Apply a balanced, water-soluble fertilizer every other month during the growing season, starting at least one month after planting. Follow the manufacturer's dosage and application recommendations.
Water the hydrangea regularly to keep soil slightly moist but never saturated. Too much water leaves the plant susceptible to a variety of foliage and root diseases such as grey mold or root rot.
Snip off spent blooms and dying leaves as they occur during the growing season. Make the cuts with pruning snips.
Prune off dead branches after winter. While some bloom production may be lost in the process, this creates a fuller, healthier plant.
Changing Bloom Color
Test the soil with a soil-test kit or by taking samples to your local agricultural extension agency. The acidity of the soil determines the color of the Gutges Mathilda blooms. Acidic soil creates blue and purple blooms, while neutral soil pH creates pink blooms.
Add hydrated lime to acidic soil to create pink blooms. The University of Georgia Cooperative Extension recommends adding 1 tbsp. lime to 1 gallon water. Drench the soil around the base of the plant with the mixture, avoiding the foliage, once a month for three months starting in March.
Add aluminum sulfate, at a rate of 1 tbsp. to 1 gallon water, to neutral soil to create bluish-purple blooms.