Deno’s GardenMy Garden

Phlox pilosa

Downy Phlox · Prairie Phlox

Family PolemoniaceaeGenus Phlox

Domed heads of pink five-petalled flowers with notched tips, on leafy stems above gravelly ground.
FlowerUnknownPublic domain

About the plant

What it is and where it grows — not part of any germination protocol.

The plant

Habit
Herbaceous Perennial, WildflowerExtension Gardener Plant Toolbox
Height
1-2 ft30-60 cmExtension Gardener Plant Toolbox
Spread
1-1.5 ft30-45 cmExtension Gardener Plant Toolbox
Flower
Pink, Purple/Lavender, WhiteExtension Gardener Plant Toolbox
Blooms
Spring, SummerExtension Gardener Plant Toolbox
Native range
Canada, lower 48 statesPLANTS Database
Hardiness zones
4-9Extension Gardener Plant Toolbox

Growing conditions

Sun
Full sun; Partial ShadeExtension Gardener Plant Toolbox
Soil
Clay, Sand, Shallow RockyExtension Gardener Plant Toolbox
Soil pH
Acid (<6.0), Neutral (6.0-8.0)Extension Gardener Plant Toolbox
Moisture
Good Drainage, Moist, Occasionally DryExtension Gardener Plant Toolbox

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Extension Gardener Plant Toolbox — NC State Extension; PLANTS Database — USDA NRCS.

Worth knowing

  • Only butterflies, moths, skippers and the largest bumblebees have tongues long enough to reach the nectar at the bottom of prairie phlox's long flower tube; shorter-tongued bees and flower flies come for the pollen instead. It is a larval host of the phlox moth. Wikipedia: Phlox pilosa

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around April 8, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on April 7, 2026.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    7 germinated in this phase.

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    7 germinated in this phase.

  3. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

    7 germinated in this phase.

  4. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    27 germinated in this phase.

  5. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 12 months from start to step 5. Germination happens during step 5, in 3 days.

33% germination in 2–3 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Phlox p. 191Public domain
Show the original text
Phlox (Polemonlaceae). Phlox seed is hard to collect as there are only a few seed in each spherical capsule and these capsules roll away as soon as ripe. As a result seed of Phlox is not readily available except for the annual P. pilosa germ. 70(7%)-40(7%)-70(7%)-40(27%)-70(33% in 2-3 d) and 40- 70(17% in 6-9 d) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Phlox p. 191. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around December 27, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 3 months from start to step 2. Germination happens during step 2, in 9 days.

17% germination in 6–9 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Phlox p. 191Public domain
Show the original text
Phlox (Polemonlaceae). Phlox seed is hard to collect as there are only a few seed in each spherical capsule and these capsules roll away as soon as ripe. As a result seed of Phlox is not readily available except for the annual P. pilosa germ. 70(7%)-40(7%)-70(7%)-40(27%)-70(33% in 2-3 d) and 40- 70(17% in 6-9 d) using fresh seed.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Phlox p. 191. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

Add to My Garden

View species page