Illustration
DeGroot's Spire
Thuja occidentalis 'DeGroot's Spire'
DeGroot's Spire 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 DeGroot's Spire
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 3–8. Expect it to reach about 15 ft tall and 3.5 ft wide at maturity, in roughly 12 years (not yet checked).
What this means
Written with AI assistance and not yet checked plant by plant against recorded sources, so treat every fact above as a starting point. Its scientific name was checked against botanical registries, an audit keeps its values consistent with the rest of the library, and a July 2026 review re-read the main facts of every plant then in the library against horticultural authorities without recording a source for each, which is why none of that counts as checked here. The source-by-source check is working through the whole library in the open, and a checked plant says so in this row.
When to plant DeGroot's Spire
Plant DeGroot's Spire 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 5, the middle of its hardy zones 3 to 8, that is April to June, or August on the fall side.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does DeGroot's Spire get?
15 fttall5 ft 7 inan adult3.5 ftwideSee DeGroot's Spire 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 DeGroot's Spire
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space DeGroot's Spire about 3.5 ft apart, center to center, so each plant has room to reach its full width.
Add DeGroot's Spire to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Good to know about DeGroot's Spire
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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Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.