Rock Soapwort in Zone 6a & 6b

Saponaria ocymoides

When to plant rock soapwort in zone 6b

Zones 6a and 6b share the same average frost dates in our data, so this page covers both.

Method: Direct sow: Direct-sow outside. Rock Soapwort doesn't transplant well, or doesn't need the extra time indoors.

Start indoors	Not typically started indoors
Direct sow / transplant outside	Apr 11–Apr 18
Estimated bloom	Apr 10 '28–Apr 17 '28 (First real harvest the season after planting)

Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 6-9 in.

Rock soapwort is a trailing rock-garden perennial, and it is a different plant from the soapwort already in this dataset.

How rock soapwort fits zone 6's season

Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Rock Soapwort takes about 1 growing season to reach full flowering, so what matters here is how many of these seasons it gets, not whether one is long enough.

Rock Soapwort is hardy in zones 2-9, so in zone 6b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.5 ft of spread at maturity.

Good companions

No standout companions recorded yet for Rock Soapwort.

Where to buy rock soapwort seeds

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