Garden phlox
Phlox paniculata 'Delilah'
Garden phlox (Phlox paniculata 'Delilah') is a perennial suited to the Colorado Front Range. It matures to about 24–32 in tall and 18–24 in wide, needs medium water, and prefers full sun to partial shade. A richly colored garden phlox in magenta-purple, fragrant and a magnet for butterflies from midsummer on. Wants regular water and good air circulation (mildew-prone in dry heat). Seen at Denver Botanic Gardens.
At a glance
Will it survive here?
- Hardiness zones
- USDA 4–8
- Water needs
- medium water
- Sun
- Best in full sun; tolerates partial shade.
- Soil
- clay, loam, sandy
- Soil pH
- 6.0–7.5
- Hail tolerance
- moderate
- Wind tolerance
- moderate
- Salt tolerance
- low
How big, what shape?
- Mature size
- 24–32 in tall and 18–24 in wide
- Planting spacing
- ~17–24 in apart
What it looks like, and when
- Bloom time
- mid summer, late summer, early fall
- Bloom color
- purple, pink
- Bloom length
- Long (several weeks)
- Foliage
- Deciduous
Who else benefits
- Pollinator value
- high
- Deer
- Not deer-resistant
- Colorado native
- No
Common problems on the Front Range
- Powdery mildew
- Spider mites
These are general tendencies for this group of plants on the Front Range, not a diagnosis. Many are stress-driven and preventable with good siting and watering. For a specific plant or an active problem, consult a certified arborist or your local CSU Extension office.
Planting & establishment
Give it steady moisture and good air flow; drought stress and crowding invite powdery mildew.
Frequently asked questions
- Is Garden phlox good for the Colorado Front Range?
- Yes, Garden phlox is a well-suited perennial for Colorado's Front Range.
- How big does Garden phlox get?
- It matures to about 24–32 in tall and 18–24 in wide.
- How far apart do I plant Garden phlox?
- Space Garden phlox about 17 in apart for a faster, fuller bed, or up to 24 in apart for a looser planting.
- Is Garden phlox hardy on the Front Range?
- Garden phlox is hardy in USDA 4–8. The Colorado Front Range spans roughly USDA 4b–6a, so it is well within range.
- How much water does Garden phlox need?
- It needs medium water once established.
- Is Garden phlox safe for dogs?
- Garden phlox is not known to be toxic to dogs, but confirm with your vet for a specific animal.
- Is Garden phlox deer-resistant?
- No. Garden phlox is not considered deer-resistant and may need protection where deer browse.
- Is Garden phlox prone to pests or disease on the Front Range?
- Garden phlox can be affected by powdery mildew and other issues common to this group on the Front Range. These are general tendencies, not a diagnosis, many are stress-driven and preventable with good siting and watering. For a specific plant or an active problem, consult a certified arborist or CSU Extension.
- How long does Garden phlox bloom?
- Garden phlox blooms for several weeks, a long-season performer on the Front Range. Bloom timing shifts a week or two with elevation and spring weather.
