When to Plant Hydrangeas

In the UK, the best time to plant hydrangeas is in spring or autumn, when the soil is moist but not waterlogged and temperatures are mild. Spring planting, from March to May, gives the plant a full season to establish before winter. Autumn planting, from September to mid-October, works just as well, especially in warmer parts of the country. Avoid planting in the middle of summer when the heat and dry conditions can stress young plants, and avoid frozen or saturated soil in winter.

Starting a Garden Display with Hydrangeas

Hydrangeas are known for their large, showy flowers and long-lasting blooms, making them a favourite for creating vibrant summer displays. They’re versatile enough for borders, containers, woodland gardens or as standalone specimens. When planted at the right time and in the right location, they become low-maintenance focal points that come back stronger each year.

Why and When to Sow or Plant

Hydrangeas are typically bought as young container-grown plants and planted out rather than grown from seed. Planting in spring gives the root system time to develop during the active growing season, while autumn planting benefits from moist soil and cooler temperatures that reduce transplant shock. The key is to allow enough time before extreme heat or cold arrives. Root establishment is essential in the first few months after planting.

Choosing the Right Hydrangea Variety

There are several types of hydrangeas, each with different growth habits, flower types and soil preferences. Hydrangea macrophylla (mophead and lacecap types) is popular for its colour-changing blooms depending on soil pH.Hydrangea paniculata produces large cone-shaped flower heads and tolerates sunnier positions. Hydrangea arborescens is hardy and reliable, while Hydrangea quercifolia offers distinctive oak-leaf foliage and autumn colour. When choosing, consider the size at maturity, flowering season and light levels in your garden.

Preparing the Planting Site

Hydrangeas prefer well-drained, moisture-retentive soil that’s rich in organic matter. They do best in partial shade, especially during the hottest part of the day, though some varieties like paniculata can handle more sun. Avoid overly dry, sandy soils or exposed, windy spots. Before planting, dig in compost or well-rotted manure to improve structure and fertility. If you're planting in a container, use a quality compost that retains moisture but drains freely.

How to Plant Hydrangeas

Dig a hole twice as wide as the root ball but no deeper than the plant was growing in its pot. Gently loosen the roots if they’re pot-bound and place the plant in the hole. Backfill with soil, firm in gently, and water thoroughly. Add mulch around the base to retain moisture and suppress weeds. In the weeks after planting, keep the soil evenly moist, especially during dry spells.

Looking After Hydrangeas

Once established, hydrangeas are relatively easy to care for. Water regularly during the first year and during prolonged dry periods in future seasons. Mulch annually in spring to improve soil quality and retain moisture. Most types benefit from light pruning, though timing depends on the variety. Macrophylla hydrangeas should be pruned after flowering, while paniculata and arborescens can be pruned in late winter or early spring to shape the plant and encourage new growth.

Looking After Hydrangeas

Once established, hydrangeas are relatively easy to care for. Water regularly during the first year and during prolonged dry periods in future seasons. Mulch annually in spring to improve soil quality and retain moisture. Most types benefit from light pruning, though timing depends on the variety. Macrophylla hydrangeas should be pruned after flowering, while paniculata and arborescens can be pruned in late winter or early spring to shape the plant and encourage new growth.

Knowing how and when to prune makes a big difference in how well hydrangeas flower year to year. For macrophylla types, avoid cutting back too hard, as they flower on old wood. Instead, remove dead stems and faded flower heads in late summer. Paniculata and arborescenstypes bloom on new growth, so they can be cut back more heavily in late winter without affecting flowering. Understanding your hydrangea variety will help you get fuller blooms and stronger structure each season.

Soil type can also influence flower colour in certain hydrangeas. In particular, Hydrangea macrophylla varieties change colour based on soil pH — turning blue in acidic soils and pink in alkaline soils. Adding aluminium sulfate to the soil can enhance blue tones, while adding garden lime can encourage pink. These colour changes won’t happen overnight, but with consistent soil adjustment, you can influence the tone of your hydrangea blooms over time.