Illustration
Fire Chief
Thuja occidentalis 'Fire Chief'
Fire Chief is grown for its foliage rather than flowers, giving the garden structure and color all season long.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Fire Chief
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 5–8. Expect it to reach about 2.5 ft tall and 2.5 ft wide at maturity, in roughly 10 years (a house reading).
Is Fire Chief toxic to dogs or cats?
- Listed as toxic to dogs and cats by University of California Agriculture and Natural Resources.
Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.
What was checked
Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Fire Chief
Plant Fire Chief in spring once the soil is workable, or by very early fall at the latest: an evergreen needs its roots down well before the ground freezes. In zone 6, the middle of its hardy zones 5 to 8, that is March to May, or August on the fall side.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Fire Chief get?
2.5 fttall5 ft 7 inan adult2.5 ftwideSee Fire Chief in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Fire Chief
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Fire Chief about 2.5 ft apart, center to center, so each plant has room to reach its full width.
Add Fire Chief to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Fire Chief's height, spread, hardiness zones, sun, water and trait tags were checked against 8 published sources on October 20, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources. Bloom was checked as well: Fire Chief bears no flowers, so there is no bloom window for a source to carry.
- conifersociety.orgAmerican Conifer Societyheight, spread and trait tags
- RHSRoyal Horticultural Societysun, water and trait tags
- southernlivingplants.comSouthern Living Plant Collectionhardiness zones, water and trait tags
- larchcottage.co.ukLarch Cottage Nurseriesheight and spread
- Purdue ArboretumExplorerhardiness zones and water
- Sooner Plant Farmhardiness zones and sun
- willowaynurseries.comWilloway Nurserieshardiness zones and trait tags
- Plant Addictssun
How the checking works, and what each standard covers, is on the verified plants page.
Where it grows wild
A garden form of Arborvitae (Thuja occidentalis)
Its wild parent is native to 21 states and 6 provinces.
Its parent's own page: Arborvitae.
United States: Connecticut, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, West Virginia, Wisconsin and 9 more
Canada: Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec
Range data from the World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 4.0, adapted) and USDA PLANTS. How the native range is credited.
Good to know about Fire Chief
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Foliage and oil hold thujone, a convulsant neurotoxin. Small culinary or homeopathic amounts are safe, but concentrated oil or large ingestions can cause convulsions and liver and kidney toxicity. per Evidence-Based Complementary and Alternative Medicine
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