Illustration
Yellow Four O'Clock
Mirabilis jalapa
Yellow Four O'Clock blooms from July through September.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Yellow Four O'Clock
Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 9–11. Expect it to reach about 2.5 ft tall and 2 ft wide at maturity, in roughly 1 year (a house reading).
Is Yellow Four O'Clock toxic to dogs or cats?
- Listed as toxic to dogs and cats by Pet Poison Helpline.
- Listed as poisonous to people by NC State Extension and Royal Horticultural Society.
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 Yellow Four O'Clock
Wait until all danger of frost has passed, then plant out Yellow Four O'Clock into warm soil; in most zones that means late spring. Planted then, it flowers from July to September.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 9, the middle of this plant's hardy range, start with zone 9 in February. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Yellow Four O'Clock get?
2.5 fttall5 ft 7 inan adult2 ftwideSee Yellow Four O'Clock 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 Yellow Four O'Clock
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Yellow Four O'Clock about 2 ft apart, center to center, so each plant has room to reach its full width.
Add Yellow Four O'Clock 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
Yellow Four O'Clock's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 7 published sources on October 27, 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.
- Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- NC State Extensionheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- University of Wisconsin HorticultureUniversity of Wisconsin-Madison Extensionheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- Outsidepridehardiness zones, sun, water, bloom months and color and trait tags
- ferriseeds.comFerri Seedsheight and bloom months and color
- RHSRoyal Horticultural Societysun and water
- University of Illinois ExtensionIllinois Extensionbloom months and color
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Yellow Four O'Clock
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
All parts are poisonous if eaten, seeds and roots the most, causing stomach upset; handling roots or crushed seeds can irritate skin. Extension offices rate it low-severity. per NC State
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.