Compass Plant (Pilot weed) care

Light

Most houseplants will scorch where compass plant thrives. Give it the windowsill you'd otherwise leave empty because everything else burned there. Requires full sun (6-8+ hours); the deep taproot allows survival of prairie fires and drought but the plant will not flower reliably in any shade. A plant moved abruptly from low light to direct sun bleaches in 48 hours — always acclimatise over a week.

Watering

Aim for every 2-4 weeks once established for compass plant, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Once established (2-3 years), virtually self-sufficient in typical UK and US conditions; water newly planted specimens regularly for the first two growing seasons while the taproot develops.

Soil and pot

Compass Plant grows best in deep, well-drained to medium clay-loam. Tolerates the heavy clay soils of its native prairie origin as long as they are not waterlogged; a deep, uncompacted soil profile is important to accommodate the extensive taproot. 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

Compass Plant sits happiest at around Low to moderate humidity and -34 to 38°C (-30 to 100°F). Adapted to continental prairie climates; grows well in both the low humidity of the central US and the higher humidity of the UK, provided good air circulation. 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 compass plant sparingly. No feeding required; native to infertile prairie soils and overly fertile conditions promote excessively tall, floppy stems that may need staking. 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 compass plant in the Growli community. Each is annotated with the most common cause so you know where to start.

• Transplant failure — The deep taproot makes established plants almost impossible to move successfully; plants older than one year will typically die if transplanted. Always site permanently and transplant only seedlings or pot-grown first-year plants.
• Slow establishment — Focuses energy on root development for the first 2-3 years and may not flower until year 3-5; patience is essential. Do not mistake slow above-ground growth for failure — check that the root crown is still viable.
• Stem borers — Borer larvae (e.g., Papaipema species) can tunnel into the thick stems, causing wilting or collapse of flowering stems. No reliable chemical control; remove and destroy affected stems.

Propagation

Sow fresh seed in autumn directly into the ground (seeds require cold-moist stratification); stratify refrigerated for 60-90 days before spring sowing. Do not attempt to divide established plants. Seedling transplants must be placed in their permanent site in the first growing season. 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

Compass Plant is pet-safe. Silphium laciniatum is not listed on the ASPCA Toxic and Non-Toxic Plant database as harmful to cats or dogs; Silphium species produce a resinous sap (rosin) but are not known to be toxic to pets. 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.

Compass Plant deep-dive guides

Every aspect of compass plant care, each with its own calibrated guide:

• Common compass plant problems & fixes
• Compass Plant watering schedule
• Compass Plant light requirements
• Best soil mix for compass plant
• Compass Plant fertilizing guide
• When to repot compass plant
• How to propagate compass plant
• How to prune compass plant
• What's eating my compass plant?
• Compass Plant growth rate & size
• Compass Plant cold hardiness
• Compass Plant temperature & humidity
• Is compass plant toxic to cats & dogs?
• Is compass plant toxic to cats?
• Is compass plant toxic to dogs?
• All 7 Silphium varieties
• Getting compass plant to bloom

Featured in these plant shortlists

Compass Plant qualifies for 11 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 pet-safe large indoor plants — Big, floor-standing houseplants the ASPCA lists as non-toxic to cats and dogs — a statement plant that is safe around pets.
• 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

Compass Plant is also known as Compass plant, Pilot weed, and Rosinweed compass plant.

• Purple Needlegrass care — light, water and common problems
• Purple Love Grass care — light, water and common problems
• Weeping Love Grass care — light, water and common problems
• All 10153 plant care guides in the Growli library