Repotting guide

When & how to repot Sea Spurge (Euphorbia paralias)

Also called Sea spurge, Sea euphorbia.

More about sea spurge

About Sea Spurge

Euphorbia paralias · also called Sea spurge, Sea euphorbia · flowering

Euphorbia paralias is a glaucous, blue-green coastal perennial in the family Euphorbiaceae, native to sandy beaches and coastal dunes around the Mediterranean, Atlantic coasts of Europe, and the Canary Islands. It forms compact, upright clumps of closely spaced, fleshy leaves arranged spirally on erect stems, and produces typical euphorboid yellowish-green cyathia in summer. It requires full sun, sharply drained sandy soil, and tolerates salt spray and drought exceptionally well. Like all Euphorbia species, it produces a caustic white latex sap and is toxic to both cats and dogs.

Mature size: 30–60 cm tall, 30–50 cm wide

Watch for — Root and crown rot in wet conditions: The roots are very sensitive to sustained moisture; in heavy or waterlogged soil, fungal rots (Phytophthora, Pythium) quickly kill the crown. Ensure perfect drainage and avoid overhead watering or mulching against the stems.

How to tell sea spurge needs repotting

Repotting on a calendar is less reliable than reading the plant. For sea spurge, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot sea spurge

Every 2–3 years, into bone-dry mix. Sea Spurge's growth habit — upright, clump-forming perennial with erect stems densely clothed in overlapping, spirally arranged, linear-oblong glaucous leaves. — sets the pace. Euphorbia paralias is a glaucous, blue-green coastal perennial in the family Euphorbiaceae, native to sandy beaches and coastal dunes around the Mediterranean, Atlantic coasts of Europe, and the Canary Islands. It forms compact, upright clumps of closely spaced, fleshy leaves arranged spirally on erect stems, and produces typical euphorboid yellowish-green cyathia in summer. It requires full sun, sharply drained sandy soil, and tolerates salt spray and drought exceptionally well. Like all Euphorbia species, it produces a caustic white latex sap and is toxic to both cats and dogs.

What size pot to step sea spurge up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Sea Spurge stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot sea spurge

Spring or summer, while sea spurge is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting sea spurge

Repot dry. Do not water sea spurge for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty sandy, gritty, very well-drained, low fertility ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set sea spurge at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep sea spurge completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for sea spurge

Sea Spurge wants sandy, gritty, very well-drained, low fertility. Naturally grows in nutrient-poor coastal sand; provide a lean, gritty mix of sand and compost at roughly 2:1, or incorporate large amounts of horticultural grit into garden soil to improve drainage. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting sea spurge — frequently asked questions

How often should you repot sea spurge?

Every 2–3 years, into bone-dry mix for sea spurge. Repot sea spurge every 2–3 years into a snug pot of sandy, gritty, very well-drained, low fertility, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does sea spurge need?

When is the best time of year to repot sea spurge?

Should you water sea spurge after repotting?

No — not straight away. Repot sea spurge into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise sea spurge after repotting?

Not immediately. Wait about 3 weeks after repotting sea spurge. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.