Maltese cross (Jerusalem cross) care

Light

Maltese cross needs sun on the leaves, not just bright ambient room light. Best in full sun, which produces the most intense scarlet flower colour and strongest stems. Tolerates partial shade (up to half a day of shade) with reasonably good flowering, though stems may need support in shadier positions. 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 maltese cross every 5–7 days in the growing season; less in cool or wet periods. 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. Prefers consistently moist soil, unlike the more drought-tolerant Lychnis coronaria. Water regularly during dry spells to maintain moisture, but ensure drainage is adequate to prevent waterlogging, which causes root rot.

Soil and pot

Maltese cross grows best in moist, fertile, well-drained loam. Grows best in moderately to well-fertilised loam with good moisture retention and reliable drainage. Adaptable to clay and sandy soils if amended. pH 6.0–7.5. Unlike rose campion, it benefits from enriched rather than poor soil. 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

Maltese cross sits happiest at around 40–70% humidity and -34 to 30°C (-30 to 86°F). Tolerates average outdoor humidity without issue. Good air circulation helps prevent powdery mildew on the foliage, which can be a problem in warm, humid conditions in the second half of summer. 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 maltese cross sparingly. Apply a balanced granular fertiliser in early spring to support strong stem growth and prolific flowering. A light balanced feed after the first flush of flowers can encourage a secondary bloom period in some seasons. 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 maltese cross in the Growli community. Each is annotated with the most common cause so you know where to start.

• Powdery mildew — White-grey fungal coating on foliage appears in warm, dry, or poorly ventilated conditions, typically in mid to late summer after flowering. Remove affected leaves, improve air circulation, and water at the base. Seldom fatal.
• Short-lived crown — Can be short-lived, especially in heavy, wet, or poorly drained soils. Division every two to three years in early spring reinvigorates plants. In ideal moist conditions it is reliably long-lived.
• Stem collapse and flopping — In windy or exposed positions, tall stems may collapse before or after flowering. Insert bamboo canes and string supports in spring, or grow compact cultivars. Staking is less needed in full sun positions with firm, moist soil.

Propagation

Divide established clumps in early spring every two to three years. Take basal stem cuttings (8–10 cm) in spring and root in gritty compost in a cold frame. Grow from seed sown in a cold frame in spring or autumn — seed-raised plants flower in their second year. 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

Maltese cross is pet-safe. Lychnis chalcedonica is not listed by the ASPCA as toxic to dogs or cats. Within the Caryophyllaceae family there are no major toxic principles known for this genus. Like related species, it may contain low levels of saponins that could cause mild gastrointestinal upset if large amounts are ingested. 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.

Maltese cross deep-dive guides

Every aspect of maltese cross care, each with its own calibrated guide:

• Maltese cross watering schedule
• Maltese cross light requirements
• Best soil mix for maltese cross
• Maltese cross fertilizing guide
• When to repot maltese cross
• How to propagate maltese cross
• Maltese cross growth rate & size
• Maltese cross cold hardiness
• Maltese cross temperature & humidity
• Is maltese cross toxic to cats & dogs?
• Is maltese cross toxic to cats?
• Is maltese cross toxic to dogs?
• Getting maltese cross to bloom

Featured in these plant shortlists

Maltese cross qualifies for 10 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 drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Best pet-safe low-maintenance plants — Non-toxic to cats and dogs and forgiving of forgotten watering — the easiest safe choices for a busy pet household.
• 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 houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• 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

Maltese cross is also known as Maltese cross, Jerusalem cross, Scarlet lightning, and Flower of Bristol.

• Polystichum makinoi care — light, water and common problems
• Polystichum neolobatum care — light, water and common problems
• Athyrium niponicum 'Red Beauty' care — light, water and common problems
• All 6887 plant care guides in the Growli library