Oak Leaf Mountain-ash
Sorbus x hybrida
Oak Leaf Mountain-ash (Sorbus x hybrida) is a tree suited to the Colorado Front Range, rated "Conditionally Recommended" on the 2024 Front Range Tree Recommendation List. It matures to about 25–40 ft tall and 20–30 ft wide, needs medium water, and prefers full sun. More resistant to fireblight.
medium water25–40 ft tall and 20–30 ft wide
Photos
- Photo 1: (c) Bernt Rostad, some rights reserved (CC BY)
- Photo 2: "Sorbus x hybrida (Sorbus austriaca cf.) (8337826230)" by Radio Tonreg from Vienna, Austria is licensed under CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/.
At a glance
Will it survive here?
- Hardiness zones
- USDA 3–6
- Water needs
- medium water
- Sun
- Best in full sun.
- Soil
- clay, loam, sandy
- Soil pH
- 6.0–8.2
- Hail tolerance
- moderate
- Wind tolerance
- moderate
- Salt tolerance
- moderate
How big, what shape?
- Mature size
- 25–40 ft tall and 20–30 ft wide
- Mature form
- Oval / upright
- Spacing / clearance
- ~30 ft of clearance
- Growth rate
- Moderate
- Lifespan
- Medium
What it looks like, and when
- Bloom time
- late spring
- Bloom color
- white
- Fall color
- Red, orange
- Foliage
- Deciduous
Who else benefits
- Pollinator value
- high
- Deer
- Not deer-resistant
- Colorado native
- No
Site factors to consider
- Critical: Insects & DiseasesMain pressure here is Fireblight and Borers, so keep it vigorous with steady water and a well-chosen site.
Common problems on the Front Range
- Fireblight
- Borers (notably borer-prone on the Front Range)
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.
Frequently asked questions
- Is Oak Leaf Mountain-ash good for the Colorado Front Range?
- Yes, Oak Leaf Mountain-ash is a well-suited tree for Colorado's Front Range, rated "Conditionally Recommended" on the 2024 Front Range Tree Recommendation List.
- Why is Oak Leaf Mountain-ash only conditionally recommended on the Front Range?
- The main catches here: Main pressure here is Fireblight and Borers, so keep it vigorous with steady water and a well-chosen site.
- How big does Oak Leaf Mountain-ash get?
- It matures to about 25–40 ft tall and 20–30 ft wide.
- How much room does Oak Leaf Mountain-ash need?
- Give Oak Leaf Mountain-ash about 30 ft of clearance from buildings, fences, and other trees so the mature canopy isn't crowded.
- What shape does Oak Leaf Mountain-ash grow into?
- Oak Leaf Mountain-ash typically grows into an upright-oval crown, taller than it is wide. This is the species' usual mature form, named cultivars (columnar, weeping, or compact selections) can differ, so check the specific cultivar.
- Is Oak Leaf Mountain-ash hardy on the Front Range?
- Oak Leaf Mountain-ash is hardy in USDA 3–6. The Colorado Front Range spans roughly USDA 4b–6a, so it is well within range.
- How much water does Oak Leaf Mountain-ash need?
- It needs medium water once established.
- How fast does Oak Leaf Mountain-ash grow?
- Oak Leaf Mountain-ash is a moderate-growing tree. Growth rate depends on water and site conditions on the Front Range.
- How long does Oak Leaf Mountain-ash live?
- Oak Leaf Mountain-ash has a moderate lifespan for a Front Range tree. Actual lifespan varies with site, water, and care.
- What color does Oak Leaf Mountain-ash turn in fall?
- Oak Leaf Mountain-ash turns red and orange in autumn. Fall color intensity varies with the season and site on the Front Range.
- Is Oak Leaf Mountain-ash native to Colorado?
- No. It is not a Colorado native, but it grows well on the Front Range.
- Is Oak Leaf Mountain-ash deer-resistant?
- No. Oak Leaf Mountain-ash is not considered deer-resistant and may need protection where deer browse.
- Is Oak Leaf Mountain-ash prone to pests or disease on the Front Range?
- Oak Leaf Mountain-ash can be affected by fireblight 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.
