Altona (Hydrangea macrophylla ‘Altona’)

Grow Hydrangea macrophylla 'Altona' in morning sun or partial shade, evenly moist fertile soil, and a protected location. Water deeply during dry periods and avoid letting the root zone dry out.

Hydrangea macrophylla 'Altona' is a mophead, or hortensia-type, hydrangea with rounded flower heads made mostly of showy sterile florets.

Hydrangea macrophylla 'Altona' typically reaches about 2 to 5 feet tall and 3 to 5 feet wide, depending on climate and growing conditions. It generally forms a compact, bushy shrub.

Give Hydrangea macrophylla 'Altona' morning sun or partial shade. It can tolerate more sun if the soil stays reliably moist, but hot afternoon sun may scorch leaves or cause wilting.

Plant Hydrangea macrophylla 'Altona' in moist, fertile, well-drained loam, clay, or amended sandy soil. Incorporate organic matter if the soil is poor, compacted, or dries quickly.

Yes, Hydrangea macrophylla 'Altona' can grow in clay soil if it is improved with organic matter and drains adequately. Avoid planting where water remains stagnant around the roots.

Hydrangea macrophylla 'Altona' is best treated as a protected bigleaf hydrangea, because winter cold can kill the old stems and flower buds. Its dependable outdoor performance varies by local climate, exposure, and winter protection.

Water Hydrangea macrophylla 'Altona' whenever the top inch of soil begins to dry, especially during hot or windy weather. Apply water slowly and deeply rather than giving frequent shallow sprinklings.

Wilting is usually caused by dry soil, excessive heat, or root stress from poor drainage. Check soil moisture first, then provide deep watering and afternoon shade while correcting drainage problems if the soil stays saturated.

The most common causes are winter damage to flower buds, pruning at the wrong time, insufficient light, or drought stress. Because this mophead flowers mainly on older stems, avoid cutting healthy stems heavily before the next bloom season.

Hydrangea macrophylla 'Altona' may be affected by aphids, scale insects, vine weevils, leaf spot, powdery mildew, and gray mold. Good air circulation, careful watering, and removal of badly affected foliage help reduce problems.

Fertilize Hydrangea macrophylla 'Altona' only when growth is weak or soil fertility is low, using a balanced slow-release fertilizer in spring. Avoid excessive nitrogen, which can produce leaves at the expense of flowers.

Plant Hydrangea macrophylla 'Altona' in spring or fall when the soil is workable and temperatures are moderate. Spring planting is preferable in colder regions so roots can establish before winter.

Yes, Hydrangea macrophylla 'Altona' can be grown in a large container with drainage holes and moisture-retentive, well-drained potting mix. Containers require more frequent watering and extra winter protection than plants in the ground.

Set Hydrangea macrophylla 'Altona' at the same depth it was growing in its nursery container, backfill with amended soil, and water thoroughly. Mulch the root zone with about 2 to 3 inches of organic mulch, keeping it away from the stems.

Prune Hydrangea macrophylla 'Altona' lightly after flowering or in mid-spring by removing spent flower heads just above a strong pair of buds. Remove dead or damaged stems at the base, but avoid cutting back healthy old wood unnecessarily.

You can cut Hydrangea macrophylla 'Altona' to the ground after severe winter damage, but it may produce few or no flowers the following season. The plant normally flowers on older stems, so hard pruning removes potential flower buds.

Propagate Hydrangea macrophylla 'Altona' most reliably from softwood cuttings taken during active growth. Root the cuttings in a sterile, evenly moist medium under bright, indirect light and high humidity.

Hydrangea macrophylla 'Altona' may be harmful if eaten and its foliage may irritate sensitive skin. Keep pets and children from chewing the plant, and wear gloves when handling it if you are prone to skin irritation.

The flowers of Hydrangea macrophylla 'Altona' may range from rose-pink to mauve or deep blue-purple, depending largely on soil acidity and available aluminum. Color can also vary with climate and growing conditions.

To encourage bluer flowers, grow Hydrangea macrophylla 'Altona' in acidic soil and use an appropriate aluminum sulfate product according to its label. Results are limited in strongly alkaline soil and may take more than one season.

Hydrangea macrophylla 'Altona' generally blooms from early or mid-summer into late summer, with flower heads often aging into red or antique tones in fall. The exact timing depends on climate and winter survival of the flower buds.

Yes, the large flower heads of Hydrangea macrophylla 'Altona' are suitable for fresh or dried arrangements. Cut stems when the florets are well developed, and allow some older flower heads to remain for seasonal interest.