Growing Four O'Clocks: A Complete Profile
By Growing Home Greens Team · July 18, 2026
Four o’clocks are named for exactly what they do: the trumpet-shaped flowers stay closed most of the day and pop open in late afternoon, releasing a strong sweet fragrance that carries into the evening. It’s a low-effort plant to get started — the seed is large and easy to handle, nothing like the dust-fine seed of many other flowers — but it needs real room once it’s growing.
What to expect
Direct sow about a week after your last frost date, seed pointed roughly 1/4 to 1/2 inch deep. Germination is quick and reliable for such a large seed. By midsummer each plant fills out into a bushy, sprawling mound 2 to 4 feet wide, so the 0.5-per-square-foot spacing isn’t a typo — this is one of the few flowers on this site that genuinely needs a full square foot or more to itself. Give it a spot at the back or corner of a bed where its bulk won’t shade out smaller neighbors.
Common problems
The most common complaint is disappointment that the flowers “won’t open” — they’re doing exactly what they’re supposed to, just not on a morning-gardener’s schedule. If plants stay stunted or fail to sprawl, check they weren’t crowded at planting; this species genuinely fights for space once mature and undersized specimens are usually just packed too tight. In zones below roughly 9, expect it to die back at frost like any other annual — the tuberous root can be dug and stored over winter the same way dahlias are, but it isn’t worth the effort unless you’re attached to a specific plant.
Where this fits in your garden
Four o’clock isn’t paired with specific companions or antagonists in our data — see the full companion guide for four o’clocks for how it’s tracked. Because it needs so much lateral room, plan its spot in the Garden Designer as a dedicated corner or border rather than trying to tuck it between other plants.
Companion planting guide for Four O'Clock · Find your planting dates
Typically viable in USDA zones 2-11. Not sure your zone? Look it up by ZIP code.
Method: Direct sow — Direct-sow outside — Four O'Clock doesn't transplant well, or doesn't need the extra time indoors.
See exact start-indoors, direct-sow, and harvest dates for your zone →
Spacing: about 2 square feet per plant (square-foot-gardening spacing).
Where to buy four o'clock seeds
Some links on this page go to retailers we may eventually earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a genuine consensus of positive, independent reviews — see the sources cited on each item.
See it growing
Search YouTube for "growing four o'clock" videos → (a live search, not a hand-picked video — results vary and aren't vetted by us)