Border forsythia
Forsythia x intermedia
Border forsythia (Forsythia x intermedia) is a shrub suited to the Colorado Front Range. It matures to about 6–10 ft tall and 6–10 ft wide, fast-growing, needs medium water, and prefers full sun. Flower buds often kill in our late spring frosts, many years it blooms only on the lower stems sheltered by snow.
On the CSU listmedium water6–10 ft tall and 6–10 ft wideZones 2–3 (keep it back from the house)Deer-resistant
Photos
- Photo 1: (c) David Dyck, some rights reserved (CC BY)
- Photo 2: (c) Ana Ka'ahanui, some rights reserved (CC BY)
- Photo 3: (c) Dr. Boli, some rights reserved (CC BY)
At a glance
Will it survive here?
- Hardiness zones
- USDA 4–8
- Water needs
- medium water
- Sun
- Best in full sun.
- Soil
- clay, loam
- Soil pH
- 6.0–7.5
- Hail tolerance
- moderate
- Wind tolerance
- moderate
- Salt tolerance
- low
- Firewise (defensible space)
- Zones 2–3 (keep it back from the house)
How big, what shape?
- Mature size
- 6–10 ft tall and 6–10 ft wide
- Planting spacing
- ~10 ft apart (7 ft for a hedge/screen)
- Growth rate
- Fast
What it looks like, and when
- Bloom time
- early spring
- Bloom color
- yellow
- Bloom length
- 2–3 weeks
- Foliage
- Deciduous
Who else benefits
- Pollinator value
- low
- Deer
- Generally deer-resistant
- Colorado native
- No
Things to know before you plant
- Spreads aggressivelyBranches root where they touch ground; expands clump steadily
Frequently asked questions
- Is Border forsythia good for the Colorado Front Range?
- Yes, Border forsythia is a well-suited shrub for Colorado's Front Range.
- What should I know before planting Border forsythia?
- The main things to know: Branches root where they touch ground; expands clump steadily
- How big does Border forsythia get?
- It matures to about 6–10 ft tall and 6–10 ft wide.
- How far apart do I plant Border forsythia?
- Space Border forsythia about 10 ft apart for a full, natural form, or about 7 ft apart for a faster hedge or screen.
- Is Border forsythia hardy on the Front Range?
- Border forsythia 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 Border forsythia need?
- It needs medium water once established.
- How fast does Border forsythia grow?
- Border forsythia is a fast-growing shrub. Growth rate depends on water and site conditions on the Front Range.
- Is Border forsythia native to Colorado?
- No. It is not a Colorado native, but it grows well on the Front Range.
- Is Border forsythia deer-resistant?
- Border forsythia is generally considered deer-resistant, though no plant is deer-proof when browse pressure is high.
- Is Border forsythia a good firewise plant near the house?
- Border forsythia is suitable in defensible-space zones 2–3, best kept back from the house rather than in the area right against the structure. This is general suitability guidance based on CSU Extension firewise plant lists, not a guarantee that any plant won't burn, a well-irrigated, well-maintained plant is the goal. Follow CSU Extension defensible-space guidance and check with your local fire district before planting in the wildland-urban interface.
- How long does Border forsythia bloom?
- Border forsythia blooms for about two to three weeks on the Front Range. Bloom timing shifts a week or two with elevation and spring weather.
