Key Facts
- Clump forming biennial or short lived perennial with erect stems.
- Blue green leaves opposite on the stem.
- Produces inconspicuous yellow green cyathia in late spring to summer.
- All parts exude a milky sap that is an irritant and is toxic if ingested.
- Prefers well drained soil and tolerates poor, dry soils.
- Grows well in full sun to part shade.
- Easily grown from seed and by stem cuttings.
- Often called mole plant because of a folk use to deter moles.
Caper Spurge is a clump forming biennial or short lived perennial grown for architectural stems and blue green foliage. It performs in poor dry soils and in sun to part shade while presenting small yellow green cyathia in late spring to summer.
Identification and key traits
Plants have erect stems with opposite blue green leaves and produce inconspicuous yellow green cyathia in late spring to summer. Typical height ranges from 24 to 39 inches and typical spread is about 12 to 24 inches depending on site fertility and self seeding.
Where to grow and best uses
Use Caper Spurge in gravel beds, dry borders and mixed perennial groups where a structural upright form is wanted. It tolerates poor dry soils and light shade but shows best form and flowering in full sun. Hardiness is roughly USDA 5 to 9 and persistence and self seeding increase in warmer climates.
Planting and spacing
Sow seed in spring or plant rooted material in well drained soil and space plants about 12 to 24 inches apart to allow room for clumping. Avoid heavy wet soils that hold water. Wear gloves when handling young plants and seeds because the plants exude a milky sap that irritates skin.
Water and soil needs
Caper Spurge prefers well drained soil and tolerates poor dry or sandy soils. Poor drainage and waterlogging increase the risk of crown rot and winter loss. Signs of moisture stress or poor drainage include yellowing foliage and soft decay at the crown or stem bases.
Propagation and after flowering care
Propagate by seed or by stem cuttings and root cuttings in warm well drained compost. Take cuttings with gloves and eye protection because of the sap. Remove spent flower heads to reduce self seeding and cut back old stems after they have finished to tidy the clump and limit volunteer seedlings.
Toxicity and safety
All parts are poisonous if ingested and the milky sap causes skin and eye irritation and can cause severe reactions. Keep plants away from children and pets and wear gloves and eye protection when cutting or dividing. Seek medical or veterinary advice for any suspected exposure.
Controlling spread and volunteers
Plants can self seed and form multistem clumps where conditions suit them. Limit spread by deadheading before seed sets and pulling seedlings while small. For persistent clumps lift and divide in spring or autumn using protection against sap when working the roots and stems.
Frequently asked questions
- How fast does Caper Spurge grow?
- Growth rate varies with soil and moisture but plants typically reach their 24 to 39 inch height within a single growing season and over one to two seasons for full clump development.
- When does it flower?
- Flowering occurs in late spring to summer with exact months varying by climate and local conditions.
- Can I propagate from cuttings?
- Yes seed and stem cuttings are common methods and cuttings root in warm well drained compost. Wear gloves and eye protection because the sap is an irritant.
- Is it invasive?
- It is not broadly listed as an aggressive invasive species but it will self seed and persist, especially in warmer gardens, so manage seedheads and seedlings to control spread.
- Is Caper Spurge safe for pets?
- No all parts are poisonous if ingested and can cause vomiting and irritation. Contact a veterinarian or poison control for guidance after any exposure.
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