Annual phlox–botanical name Phlox drummondii— is a bushy annual with neat green leaves and clusters of small pink, red, purple, blue, and white flowers that appear throughout the summer. Leaves are lance-shaped and narrow.
Annual phlox is a Texas native. Seeds can be sown outdoors after all danger of frost is past. In mild winter and desert regions, seeds can be sown in the fall.
Annual phlox is a good choice for bedding. It can serve as a ground cover for summer-blooming bulbs.
Get to Know Annual Phlox — Phlox drummondii
- Plant type: Annual
- Growing Zones and range: Zones 4-9
- Hardiness: Tender
- Height and width: 6 to 20 inches (15-50cm) tall; up to 10 inches (25cm) or more wide
- Foliage: Narrow, inversely lance-shaped to nearly ovate leaves 1-3 inches long
- Flowers: Tight clusters of star-shaped flowers 1 inch across
- Flower colors: Shades of pink, red, salmon, purple, mauve, and white; many flowers are bicolored
- Bloom time: Summer to frost
- Uses: Bedding, edging, rock gardens, containers
- Common name: Annual phlox, Drummond phlox
- Botanical name: Phlox drummondii
- Family: Polemoniaceae
- Origin: Noth America
Where to Plant Annual Phlox — Phlox drummondii
- Plant annual phlox in full sun.
- Grow annual phlox in humus-rich, well-drained soil.
When to Plant Annual Phlox — Phlox drummondii
- Sow annual phlox seeds directly in the garden in early spring in Zones 2-6. In Zones 7-11 sow seeds in late autumn for winter or early spring bloom.
Planting and Spacing Annual Phlox — Phlox drummondii
- Space annual phlox 6 to 8 inches apart. Plant annual phlox in groups of a dozen plants or more for best effect.
How to Water and Feed Annual Phlox — Phlox drummondii
- Annual phlox needs moderate moisture; keep the soil evenly moist.
- Fertilize annual phlox with an all-purpose fertilizer every 4 to 6 weeks.
Annual Phlox Care — Phlox drummondii
- Remove spent blooms to encourage new flowers.
- Heat will slow or stop annual phlox; the plant will revive in the fall.
Annual Phlox Varieties to Grow
- ‘Dwarf Beauty’ grow to 6 inches tall.
- ‘Brilliant’ grows to 2 feet tall.
- Globe Mixed are dwarf mounding cultivars.
Annual Phlox Frequently Asked Questions
Q: When do I plant annual phlox in the garden?
A: Annual phlox is slightly resistant to frost. You can sow seeds indoors 8 to 10 weeks before the last frost. Set young plants into the garden a few weeks before the last frost as long as the soil is workable. Place phlox where it can grow in full sun.
Q: How do I start phlox from seed?
A: Sow seeds indoors 8 to 10 weeks before the outdoor planting date. Sow seeds in individual pots; seedlings do not like transplanting. Start seeds in a cool room; this is important for germination. Cover the seeds completely; they need darkness to germinate. Be careful not to overwater; young plants are susceptible to damping off.
Q: What care do phlox need in the garden?
A: Fertilize phlox monthly with soluble plant food. Keep phlox well-watered. Remove faded flowers. Cut leggy plants back to encourage compactness. Phlox is fairly heat-resistant but may decline in mid-summer heat.