If you’re after a hydrangea that stands out from the crowd, Hydrangea serrata ‘Kiyosumi sawa’ is a wonderful choice. This rare and refined variety offers elegant lacecap flowers and attractive foliage in a compact, easy-to-manage form.
Plant Description
‘Kiyosumi’ is a compact, upright to rounded, bushy deciduous shrub reaching aroun 1m (3ft) in height.
It features prominently veined, ovate, pointed dark green leaves that often show appealing maroon or burgundy flushes, especially on new growth. The overall effect is a graceful medium-sized shrub with rich, textured foliage that provides interest even when not in flower.
Flowers
The inflorescence is a classic lacecap type, featuring a generous cluster of small fertile pinkish-white flowers at the centre surrounded by larger sterile flowers on the outside. Deepish pink to ruby red buds open to reveal white blooms with delicate red to pink margins, creating a pretty picotee effect. These flowers sit beautifully against the dark foliage, giving the plant a refined, two-toned appearance.
Size and Growth Habit
Hydrangea serrata ‘Kiyosumi sawa’ is naturally compact, typically reaching around 1 metre or less in height and width. It responds well to pruning, making it suitable for smaller gardens, courtyards, or containers.
Landscaping Uses and Planting Ideas
The delicate structure of the flowers and attractive foliage make ‘Kiyosumi sawa’ ideal for lightly shaded positions where its subtle beauty can be appreciated up close. It suits woodland-style gardens, shaded borders, and Asian-inspired designs.
Suggested planting schemes:
- Plant in groups of three or five for a dramatic drift under trees.
- Pair with a low groundcover for contrast.
- Use in mixed shady borders or near water features where dappled light enhances the flower detail.
- Excellent for large pots on shaded patios.
- Consider planting under trees.
Companion Plants
Good companions include other shade lovers that thrive in similar conditions:
- Ferns (such as Japanese painted fern or autumn fern) for fine texture contrast.
- Hostas and Heucheras for varied foliage colour.
- Astilbes and Tiarella for additional summer flowers.
- Low-growing Japanese forest grass (Hakonechloa) for graceful movement.
- Early spring bulbs like snowdrops or bluebells for seasonal interest before the hydrangea leafs out.
Hydrangea serrata ‘Kiyosumi sawa’ – Care Guide
Hydrangea serrata ‘Kiyosumi sawa’ is relatively low-maintenance when given the right conditions.
- Position: Best in light to dappled shade. In warmer or hotter climates, provide more shade and protection from afternoon sun.
- Soil: Humus-rich, moist but well-drained soil. It appreciates a slightly acidic to neutral pH.
- Watering: Keep the root zone consistently moist, especially during hot, dry periods. Extra summer watering is often needed in warmer regions.
- Mulching: Apply a generous layer of organic mulch each spring to retain moisture, cool the roots, and improve soil structure.
- Pruning: Prune lightly after flowering if needed to maintain shape and size. Remove any dead or damaged wood in late winter.
- Fertilising: Use a balanced, slow-release fertiliser for shrubs in spring, or apply well-rotted compost. Avoid high-nitrogen feeds that can encourage leafy growth at the expense of flowers.
- Pests & Problems: Generally trouble-free, though watch for occasional aphids or powdery mildew in humid, stagnant conditions. Good air circulation helps prevent issues.
Origin
This attractive variety is named after Mount Kiyosumi in Japan, where it was originally discovered.
Hydrangea serrata ‘Kiyosumi sawa’ brings refined beauty and manageable size to shaded gardens. Its combination of dark foliage and picotee lacecap flowers makes it a standout choice for gardeners seeking something a little different.
