Carex ‘Blue Wave’

Carex 'Blue Wave' is a weeping sedge that solves the two problems most groundcovers cannot solve at once: it sits happily in a damp low spot, and it survives a dry summer. It forms a soft mound about 40cm tall and 50cm wide, with fine blue green blades that arch over and ripple in wind. Mass planted, it looks like water.

Why you'll love it

• Wet feet or dry ground. It tolerates soggy soil that rots most strappy plants, and once established it also handles drought, so it suits ground that swings between the two.
• Blue green colour with no flowers to manage. The foliage does all the work, which means no spent flower heads and no seasonal gap.
• The weeping habit fills gaps. Blades arch outwards rather than standing upright, so a planting closes over bare mulch faster than the plant size suggests.
• Low maintenance and pet friendly. One shear a year is the whole job, and it is not toxic to cats or dogs.

Where it works best

Mass planting and groundcover. Plant 40cm apart for a flowing mass planting, which is roughly six plants per square metre. Run it across a slope or a wide bed and the mounds knit into one continuous surface.

Borders and rockeries. The soft edge sits well against stone, steel and concrete. Use it to break the line where paving meets planting.

Damp corners and pots. It is a sensible choice for the low point of a garden that stays wet after rain, and it holds its shape in a pot on a windy balcony.

Growing Carex Blue Wave in Australia

Position and climate. Full sun to part shade. It suits cool temperate, warm temperate, subtropical and Mediterranean gardens, and it is frost hardy, so cold southern districts are no obstacle. Coastal and salt tolerant too, which makes it useful on exposed foreshore blocks.

Soil. Almost any soil works, including heavy clay that holds water. There is no need to raise the bed for this one. Mulch 50mm deep between plants while they fill in.

Water and feed. Water twice a week through the first summer to build the root mass, then step back. A controlled release fertiliser in early spring keeps the colour strong; more than that gives you soft floppy growth.

Pruning. Shear the clumps back to about 10cm in late winter. Old blades otherwise accumulate in the centre and the mound loses its shape from the middle out.

What to expect when it arrives

Two sizes are sold: tube stock, and a 140mm pack of 10. Tubes are young plants with a full root plug, cheap enough to plant in the numbers a mass planting needs, and they reach full size within two seasons. The 140mm plants are a season ahead and give a quicker result on a smaller area.

Sedges travel well because the foliage bends instead of breaking, though creased blades are normal on arrival and grow out. Plants are delivered Australia wide, with delivery from $29.95 and a minimum order of $300 before delivery. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Designing with ornamental grasses
• Browse grasses and strappy leaf plants
• What to plant in a waterlogged garden
• More plants that are safe around pets

Common questions

How many do I need per square metre?

Six at 40cm spacing. A pack of 10 covers a little under two square metres, or about four metres of single row border.

Will it cope with a spot that floods after storms?

Yes, within reason. It tolerates wet feet and periods of standing water, which is why it works in swales and low corners. Permanently submerged ground is a different matter.

Does it spread or seed around?

It grows as a slowly widening clump rather than a runner, so it stays where it is planted. Flowering is insignificant and it is not a self seeding nuisance in a mulched bed.