Flowering before any other hydrangea, Hydrangea serrata 'Diadem' is a compact, spreading, deciduous shrub laden with delicate lacecap flowers, up to 6 in. across (15 cm), in early summer. The flower heads are composed of large, showy sterile sepals radiating around a central cluster of tiny fertile florets. The florets are pale pink or light blue, depending on the soil pH. The profuse blossoms are beautifully framed by the foliage of narrowly-ovate, pointed, yellow-green leaves. 'Diadem' is an outstanding landscape shrub that is ideal for small gardens.
- Winner of the prestigious Award of Garden Merit of the Royal Horticultural Society
- This deciduous shrub enjoys a round, bushy habit, typically growing up to 3 ft. tall and wide (90 cm)
- A full sun or part shade lover, it is best grown in rich, medium moisture, well-drained soils. Tolerant of sun if the soil remains moist.
- No serious pest or disease issues. Watch for aphids, capsid bug, hydrangea scale and vine weevil.
- Perfect from foundation plantings to container plantings. Massed in a sheltered location or as an accent plant.
- To change the color of your Hydrangea, add aluminum sulfate to the soil to make the flowers bluer or add lime to the soil to make them pinker. Treatment should occur ahead of time (late fall or early spring)
- This beautiful deciduous shrub should be pruned after flowering by cutting back the stems to a pair of healthy buds. Prune out weak or winter-damaged stems in early spring.