Phlox (Annual) Growing Guide

Phlox drummondii

Phlox (Annual)

Crop Rotation Group



Well-drained soil of average fertility.


Full sun.

Frost tolerant

Limited, though young seedlings often survive light frosts.


Mix a light application of a balanced organic fertiliser into the soil prior to planting. In midsummer, drench plants with a liquid fertiliser to prolong bloom time.


Annual phlox is a heavy bloomer that looks best when grown in clumps or masses. It is an excellent flower to naturalise along fences, or you can include it in a wildflower meadow.


Single Plants: 15cm (5") each way (minimum)
Rows: 15cm (5") with 15cm (5") row gap (minimum)

Sow and Plant

Sow annual phlox seeds indoors to get a head start, or you can plant the seeds where you want the plants to grow two weeks before your last spring frost is expected. Transplant carefully, without disturbing the roots.
Our Garden Planner can produce a personalized calendar of when to sow, plant and harvest for your area.


Annual phlox attracts butterflies and beneficial pollinators. In warmer areas, annual phlox sometimes reseeds but it is never invasive. Colours include rose pink, white, purple and light pink.


After annual phlox has bloomed heavily for a few weeks and is slowing down, cut back the plants by half their size. The new growth will produce a second flush of flowers.


In humid areas, powdery mildew often appears on tired plants in late summer.

Planting and Harvesting Calendar

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Pests which Affect Phlox (Annual)