Hydrangea – Hydrangea macrophylla

Although the Hydrangea grows wild along the banks of rivers in Japan and China, here it is often thought of primarily as a garden plant. It can, however, be used as a house plant while in flower.

Flowers and flowering

The Hydrangea has large and striking flowerheads. Some are white or pink, but if you make the potting mixture acid the flowers will turn blue. A blue-flowered Hydrangea will turn pink if it is planted in an alkaline mixture.

As a pot plant, the Hydrangea has only a relatively short life in flower. Afterwards it should be planted out in the garden or disposed of. Plants that have been forced into bloom early can be bought in spring and they will remain decorative in a cool room for 8-10 weeks. Plants bought in the summer carry on blooming through to autumn.

The plant is compact and bushy and can spread up to 60cm (2ft).

Hydrangea macrophylla is the most suitable for growing as a pot plant.Hydrangea - Hydrangea macrophylla

If you want to vary the colour of your plant from white or pink to blue or purple, grow it in an acid potting mixture. You can also water it with alum (aluminium sulphate). This is sold at florists or garden centres as a Hydrangea colorant. You should follow the pack instructions but you will have to apply it regularly or the flowers will revert to pink. Water it with alum every fortnight once the first tiny flowerbuds are visible.

Display ideas

The Hydrangea adds a touch of luxury and elegance to a windowsill. To achieve a lovely floral show, arrange 3-4 plants in separate clay pots on the terrace or patio.


1. Take cuttings in June or July. Put in water and roots will develop.

2. Pot up in a mixture of sphagnum moss and a soil-based potting compost.

3. Pinch out the cuttings to make them bushier. Pinch the growing tips just above a pair of well-developed leaves. Continue doing this until the end of July.

4. Water the new plants daily until November then move them to a cool but frost-free position until January. During winter keep new plants in a cool room.

3. Cut it right back in January to the lowest pair of buds. Put it in a warm place and water sparingly until the first flowerbuds appear.


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Looking after your plant

1. To keep a Hydrangea for a second year cut off the flower-heads after the plant has finished flowering and keep it cool.

2. Water the plant sparingly but do not let it dry out completely. Make sure that you keep it cool and out of direct sunlight.

Plant Problems

Red spider mites can be difficult to control on this plant. Their webs will be visible on the undersides of leaves.

Treatment: If you detect them early, simply wash them off the leaves by frequent spraying. If the attack is serious, use a suitable pesticide.

Young leaves and buds are sticky and misshapen. This is caused by greenfly or aphids.

Treatment: If the attack is minor, wash the insects off with soapy water. If the attack is more serious, spray with a suitable insecticide or use a systemic insecticide.

Leaves wilt and become brown at edges. This is caused by lack of water.

Treatment: During the growing season, water generously. If the plant looks droopy, immerse it, pot and all, in a bucket of water until bubbles stop appearing.

White powder on the leaves is a sign of mildew. Treatment: Treat plant with a fungicide.


This is an easy plant to care for on a short-term basis but it does need a lot of water in summer.

  • Potting: The Hydrangea thrives in a soil-based potting mixture with added sphagnum moss to make it free-draining. Repot in January or February.
  • In the growing season water generously. If it is very hot water twice a day. In autumn and winter, water just enough to keep the plant from drying out.
  • Feeding: Add a liquid plant fertilizer during the flowering season. Do not feed in winter.


  • Light: Good light in an east- or west-facing window would suit this plant. On a patio it needs a sheltered position in the shade of other plants.
  • Temperature: In summer the ideal temperature is around 20°C (68°F); in winter it is around 4°C (40°F).

With its round white, pink or blue flowers, the Hydrangea is an attractive and decorative plant to grow in the greenhouse, on a windowsill or on your patio.

English: Hydrangea macrophylla - Hortensia hyd...

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When to buy

  • Hydrangea can be bought from early spring through the summer months.
  • Choose bushy plants with large dark green leaves and stiff stems. Thin, weak stems will not be able to support heavy flowerheads.
  • You can use a Hydrangea as a house plant on a one-season throw-away basis or you can grow it in a tub on the porch or patio, year after year. Indoors, it may be tricky to bring into flower a second time.

H. involucrata is a small, spherical shrub up to 75 cm tall, which flowers from July-September. It has bristly-haired, oblong leaves, small flowerheads up to 12 cm across, consisting of large numbers of bluish-purple, fertile flowers and large, white, sterile flowers; the dead flowers remain on the plant until winter. H. macrophylla hybrids are 70-150 cm tall and flower from July-September; ‘Ayesha’ has fragrant, lilac-white flowers; ‘Blue Wave’ is a vigorous, broad shrub which produces blue flowers in acid soil, otherwise pink or lilac flowers; ‘Mariesii Perfecta’ has large, lilac pink, sterile flowers; ‘Veitchii’ (Lace cap) is an open shrub with large, white, sterile flowers; it likes lime-rich soil and shade. For neutral or acid, moist soil, also by the sea, in the sun or semi-shade.

Prune after flowering. In spring, only remove shoots to rejuvenate the plant. If the buds at the top of the plant freeze, it usually does not flower. H. paniculata is up to 4 m tall and flowers in August-September. It has oval, pointed leaves which turn yellowish-brown in autumn and large, full, white or pink flowerheads; ‘Grandiflora’ has even larger, white flowerheads, which turn pink and then red, consisting virtually only of sterile flowers. This vigorous plant requires moist soil; prune back every year. H. petiolaris (syn. H. anomala subsp. Pictiolaris, H. scandens), climbing hydrangea, grows vigorously from the second/third year to a height of 2 m. It can be trained along walls to 7 m, and flowers in June-July. It has adventitious roots, leaves 4-10 cm long, and flat, white flowerheads, 20 cm across. It is suitable as ground cover or for a north-facing wall in the (semi-) shade in lime-free soil.

Bigleaf Hydrangeaen (Hydrangea macrophylla)

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Prune only for a flat shape; propagate from top cuttings in spring. H. quercifolia, oak-leaved hydrangea, is less winter-hardy. It flowers from July-September, and has lobed, spiny leaves, which are hairy and white-felted on the underside, turning purplish-bronze in autumn, and long, white or purplish-red clusters of flowers; grow in lime-free soil and cover the base in winter. H. serrata (syn. H. macrophylla subsp. Scrrata) is an upright shrub, 1-1.5 m tall, which flowers in July-August. It has slender, almost black stems, lanceolate, dull green leaves, 5-15 cm long, and flat, pale purple flowerheads up to 14 cm across; for blue flowers, grow in acid soil; ‘Acuminata’ has pink flowers with bluish-pink, sterile flowers; ‘Blue Bird’ has red leaves in autumn and lilac flowers and white, sterile flowers; ‘Rosalba’ has white flowers, later spotted with red; requires acid or neutral soil; prune after flowering. In general, this shrub requires sun or semi-shade. Water liberally during dry periods and feed every year (spring). Flowers of H. macrophylla and H. paniculata are suitable as dried flowers. Propagate from summer cuttings.

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