Rock Soapwort in Zone 7a & 7b

Saponaria ocymoides

When to plant rock soapwort in zone 7b

Zones 7a and 7b 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	Mar 27–Apr 3
Estimated bloom	Mar 26 '28–Apr 2 '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 7's season

Zone 7b's frost-free window runs about 198 days, from April 10 to October 25. 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 7b 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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