Growing Annual Phlox: A Complete Profile
By Growing Home Greens Team · August 10, 2026
Annual phlox is a compact, fast, and easy bedding flower in unusually bright, saturated colors, worth telling apart from the taller, perennial garden phlox that shares the common name but grows and behaves quite differently.
Sowing it in the dark
Direct-sow in spring as soon as the soil is workable, or start indoors 4 to 6 weeks before your last frost. Unlike many flowers on this site, phlox seed needs darkness to germinate, not light, so cover it with about 1/8 inch of fine soil rather than leaving it exposed. Germination takes 5 to 10 days at 60-65°F. Space plants 8 to 12 inches apart.
Handle transplants gently
Phlox dislikes root disturbance more than most bedding annuals, so if starting indoors, handle the move to the garden carefully and avoid letting roots get pot-bound beforehand. It thrives in full sun with rich, moist, well-drained soil, and works as well in containers and borders as it does in a dedicated cutting row.
Cutting for a vase
Harvest fresh stems once about half the flowers on a stem have opened, which balances bloom count against the longest usable vase life.
Phlox has no recorded companions or antagonists in our data. See the full companion guide for phlox for how it’s tracked. At 2 plants per square foot, it works well as a dense border filler or container plant in the Garden Designer.
Source: Phlox: Key Growing Information, Johnny’s Selected Seeds.
Companion planting guide for Phlox (Annual) · Find your planting dates
Typically viable in USDA zones 2-11. Not sure your zone? Look it up by ZIP code.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Phlox (Annual) tolerates either.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Phlox (Annual) plants fit per square foot?
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 0.5-1.5 ft.
Varieties worth considering
- Straight-species annual phlox (Phlox drummondii): Johnny's Selected Seeds sells this species in a range of named color mixes and single strains; the growing requirements are consistent across them, so the species itself covers what matters for care. (source)
- 'Cherry Caramel' annual phlox (best for: cut-flower stem length): Johnny's Selected Seeds describes this as having long stems and an antique look, a perfect cut flower and border plant, bred longer-stemmed than a standard bedding mix. (source)
- 'Art Shades Mix' annual phlox (best for: fast-growing bouquet color): Johnny's Selected Seeds lists this as a fast-growing accent flower for bouquets and borders, a mixed-color alternative to the single-tone Cherry Caramel above. (source)
Cited from the source shown next to each variety. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement.
Where to buy phlox seeds
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may 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 phlox (annual)" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
%3A%20An%20easy%20bedding%20and%20cut%20flower%20in%20saturated%20colors%2C%20distinct%20from%20the%20taller%20perennial%20garden%20phlox%2C%20and%20a%20plant%20that%20dislikes%20root%20disturbance%20more%20than%20most.)
Pin this for later
Growing Phlox (Annual): An easy bedding and cut flower in saturated colors, distinct from the taller perennial garden phlox, and a plant that dislikes root disturbance more than most.
Save to Pinterest