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Plant care

Mediterranean Sea Holly (Pyrenean Eryngo) care

Eryngium bourgatii

Also called Mediterranean Sea Holly, Pyrenean Eryngo, Mediterranean Eryngo.

RHS H6USDA 4-9Pet-safeIndoor 45–60 cm tall in flower

Watering rhythm

Direct sun (at least 4-6 hours)

Low — water young plants to establish, then rely on rainfall

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Light

Direct sun (at least 4-6 hours)

Soil

Dry to moderately moist, well-drained, poor to moderately fertile

Humidity

Low to moderate

Temp

-20°C to 30°C

Pet safety

Pet-safe

Mature size

45–60 cm tall in flower

Care at a glance

Light

Mediterranean Sea Holly needs sun on the leaves, not just bright ambient room light. Needs a minimum of six hours of direct sun daily; the metallic blue colouring of stems and bracts intensifies in full sun and fades noticeably in shade. A south or west-facing windowsill in the northern hemisphere is the default; anywhere else, expect the plant to stretch and pale out within a season.

Watering

Water mediterranean sea holly low — water young plants to establish, then rely on rainfall. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Once the deep taproot is established the plant tolerates prolonged dry spells well; consistent overwatering is more harmful than underwatering.

Soil and pot

Mediterranean Sea Holly grows best in dry to moderately moist, well-drained, poor to moderately fertile. Gritty, alkaline or neutral loam suits it perfectly; avoid rich, moisture-retentive soils which cause lush, floppy growth and root rot. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Mediterranean Sea Holly sits happiest at around Low to moderate humidity and -20°C to 30°C (-4°F to 86°F). Prefers dry, open conditions with good air movement; stagnant, humid air around the crown in winter increases the risk of fungal disease. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed mediterranean sea holly sparingly. No feeding required; overly fertile soil reduces the intensity of the blue colouring and produces weak, flopping stems. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on mediterranean sea holly in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Powdery mildew — Can appear in dry spells with poor air circulation; improve ventilation around plants and avoid wetting foliage. Badly affected growth should be removed.
  • Slugs and snails — Young plants and newly emerging spring growth are vulnerable to slug damage; protect with grit mulch or slug traps, particularly through spring.
  • Root rot in heavy soils — Waterlogged clay in winter causes rapid root and crown rot; always improve drainage before planting and avoid mulching directly over the crown.

Propagation

Root cuttings taken in late winter are the most reliable method. Seed can be sown fresh in autumn in a cold frame. Division is possible but plants are slow to re-establish due to the taproot. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Mediterranean Sea Holly is pet-safe. Eryngium is not included in the ASPCA list of plants toxic to cats or dogs; the genus is considered non-toxic, though spiny foliage may cause physical irritation. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Mediterranean Sea Holly care — frequently asked questions

What is the common name for Eryngium bourgatii?

Eryngium bourgatii is most commonly called Mediterranean Sea Holly, but it is also known as Mediterranean Sea Holly, Pyrenean Eryngo, Mediterranean Eryngo. The names refer to the same species, so care instructions for Mediterranean Sea Holly apply identically to anything sold as Pyrenean Eryngo.

How much light does mediterranean sea holly need?

Mediterranean Sea Holly grows best in direct sun (at least 4-6 hours). Needs a minimum of six hours of direct sun daily; the metallic blue colouring of stems and bracts intensifies in full sun and fades noticeably in shade.

How often should I water mediterranean sea holly?

Water mediterranean sea holly low — water young plants to establish, then rely on rainfall. Once the deep taproot is established the plant tolerates prolonged dry spells well; consistent overwatering is more harmful than underwatering. The finger-test (or lifting the pot to feel its weight) beats a fixed weekly calendar because pot size, light, and season all change how fast the soil dries.

Is mediterranean sea holly toxic to cats and dogs?

Mediterranean Sea Holly is pet-safe. Eryngium is not included in the ASPCA list of plants toxic to cats or dogs; the genus is considered non-toxic, though spiny foliage may cause physical irritation.

What USDA hardiness zone does mediterranean sea holly grow in?

Mediterranean Sea Holly is rated for USDA zone 4-9 and RHS hardiness H6. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Mediterranean Sea Holly deep-dive guides

Every aspect of mediterranean sea holly care, each with its own calibrated guide:

Featured in these plant shortlists

Mediterranean Sea Holly qualifies for 7 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

  • Best pet-safe houseplants — Houseplants the ASPCA lists as non-toxic to cats and dogs — every one verified against the ASPCA toxic and non-toxic plant list.
  • Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
  • Best pet-safe flowering plants — Flowering houseplants the ASPCA lists as non-toxic to cats and dogs — colour and blooms in a pet home, without the worry.
  • Best pet-safe plants for bright light — Non-toxic to cats and dogs and happy in a bright, sunny spot — safe plants for your best-lit windowsill.
  • Best houseplants for full sun — Houseplants that want direct sun — the species for a hot south or west-facing windowsill where shade-lovers scorch.
  • Best cat-safe plants — Houseplants the ASPCA lists as non-toxic to cats (and dogs) — safe greenery for a home with a curious cat.
  • Best dog-safe plants — Houseplants the ASPCA lists as non-toxic to dogs (and cats) — safe greenery for a home with a curious dog.
  • Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Mediterranean Sea Holly is also known as Mediterranean Sea Holly, Pyrenean Eryngo, and Mediterranean Eryngo.