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Plant care

Nettle-leaved Bellflower (Bats-in-the-Belfry) care

Campanula trachelium

Also called Nettle-leaved Bellflower, Bats-in-the-Belfry, Coventry Bells, Throatwort.

RHS H6USDA 4-8Pet-safeIndoor 60–90 cm tall

Watering rhythm

Medium indirect light (a couple of metres from a window)

Moderate — keep consistently moist, especially in summer

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Light

Medium indirect light (a couple of metres from a window)

Soil

Fertile, humus-rich, moist but well-drained

Humidity

Moderate

Temp

-20°C to 28°C

Pet safety

Pet-safe

Mature size

60–90 cm tall

Care at a glance

Light

The Goldilocks zone. Not the south-facing windowsill (too hot, too direct), not the back of the room (too dim, growth stalls). Prefers partial shade to dappled light under deciduous canopy; flower colour is often richer in shade, and plants do not wilt as readily as in full sun. If you can't decide, a free phone lux-meter app aimed at the leaf at noon should read between 800 and 1,500 lux.

Watering

Watering nettle-leaved bellflower: moderate — keep consistently moist, especially in summer. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Needs more moisture than dry-soil bellflowers; mulching around the base in spring helps retain moisture during the flowering period.

Soil and pot

Nettle-leaved Bellflower grows best in fertile, humus-rich, moist but well-drained. Thrives in loamy, woodland-type soils with added leaf mould; tolerates clay if not waterlogged, and grows well on chalk soils with added organic matter. 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

Nettle-leaved Bellflower sits happiest at around Moderate humidity and -20°C to 28°C (-4°F to 82°F). Adapted to the ambient humidity of woodland margins; no special misting required in outdoor cultivation. 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 nettle-leaved bellflower sparingly. Apply a balanced general fertiliser (e.g. 10-10-10) once in early spring to support the tall flowering stems; avoid high-nitrogen feeds that produce leafy growth without flowers. 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 nettle-leaved bellflower in the Growli community. Each is annotated with the most common cause so you know where to start.

  • Powdery mildew — Common on plants stressed by dry conditions at the root in summer; maintain soil moisture and remove affected leaves promptly — do not overhead-water to compensate.
  • Slugs — Young shoots and developing flower spikes are eagerly grazed; protect new growth in spring with iron phosphate pellets or physical barriers.

Propagation

Divide clumps in spring or autumn; sow seed in containers in a cold frame in spring (surface-sow, as seeds need light); basal cuttings taken in spring root readily in gritty compost. 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

Nettle-leaved Bellflower is pet-safe. Campanula species are listed as non-toxic to cats and dogs on the ASPCA Toxic and Non-Toxic Plant database; no toxic principles have been documented for this genus. 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.

Nettle-leaved Bellflower care — frequently asked questions

What is the common name for Campanula trachelium?

Campanula trachelium is most commonly called Nettle-leaved Bellflower, but it is also known as Nettle-leaved Bellflower, Bats-in-the-Belfry, Coventry Bells, Throatwort. The names refer to the same species, so care instructions for Nettle-leaved Bellflower apply identically to anything sold as Bats-in-the-Belfry.

How much light does nettle-leaved bellflower need?

Nettle-leaved Bellflower grows best in medium indirect light (a couple of metres from a window). Prefers partial shade to dappled light under deciduous canopy; flower colour is often richer in shade, and plants do not wilt as readily as in full sun.

How often should I water nettle-leaved bellflower?

Water nettle-leaved bellflower moderate — keep consistently moist, especially in summer. Needs more moisture than dry-soil bellflowers; mulching around the base in spring helps retain moisture during the flowering period. 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 nettle-leaved bellflower toxic to cats and dogs?

Nettle-leaved Bellflower is pet-safe. Campanula species are listed as non-toxic to cats and dogs on the ASPCA Toxic and Non-Toxic Plant database; no toxic principles have been documented for this genus.

What USDA hardiness zone does nettle-leaved bellflower grow in?

Nettle-leaved Bellflower is rated for USDA zone 4-8 and RHS hardiness H6. Outside that range, grow it as a container plant that overwinters indoors before the first hard frost.

Nettle-leaved Bellflower deep-dive guides

Every aspect of nettle-leaved bellflower care, each with its own calibrated guide:

Featured in these plant shortlists

Nettle-leaved Bellflower qualifies for 9 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 low-light houseplants — Houseplants that need no direct sun and cope with a north-facing room or a spot well back from a window.
  • Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
  • Best pet-safe low-light plants — Non-toxic to cats and dogs AND happy with no direct sun — the two hardest constraints to satisfy at once.
  • 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 bedroom plants — Non-toxic to cats and dogs and happy in lower light — calming greenery for a bedroom where a pet often sleeps too.
  • 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

Nettle-leaved Bellflower is also known as Nettle-leaved Bellflower, Bats-in-the-Belfry, Coventry Bells, and Throatwort.