Sorbus americana ‘Dwarfcrown’
The Red Cascade™ Mountain Ash is a tree of limited height and width, reportedly growing no more than 20′ tall and 8′ wide. It has clusters of white flowers that eventually turn into orange, then red fruit, smaller in size than a marble. Green pinnately compound leaves turn yellow in fall, some years with quite a spectacular show. Leaves sometimes emerge with a yellowish edge in the spring.
This is a straight and narrow tree with stout twigs, growing almost candelabra-like from the main leader. We have seen no insect or disease problems. As far as messy fruit, in most areas the birds strip the tree of its berries before they hit the ground, but I don’t think you can count on that every year.
We have found this tree easy to grow and transplant, with minimal pruning required. This is a favorite street tree in Mount Vernon, according to the Parks Maintenance Supervisor, because he can pretty much forget about this tree after its established. It maintains a relatively short oval form all on its own.
We have also found this tree to be a very tough street tree survivor. Many other trees planted in less than desirable locations, with minimal maintenance (i.e. watering), will end up with dieback (Raywoods, Crabs, Cherries, Oaks). This tree responds to drought with smaller leaves and canopy, apparently until the root system becomes established. This is especially a nice feature where watering is inadequate.
I have seen excellent specimens growing in small 24”x24” sidewalk openings for the last several years. Some have been run into, abused, and neglected, but still somehow perform quite well. If you are looking for a tough street tree with a compact crown for under power lines, where fruit may not be a problem, the Red Cascade Mountain Ash tree is a good selection. It can also be quite showy in the spring and fall for a special garden location.
Let me know what your experience has been with this tree.
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Jim Barborinas
Owner of Urban Forest Nursery, Inc.
ISA Certified Arborist #0135
ASCA Registered Consulting Arborist #356
15119 McLean Rd.
Mount Vernon, WA 98273
jim@urbanforestnursery.com
Curious how Red Cascade™ Mountain Ash fits in landscapes and urban spaces?
Here are some common questions people ask about this tree:
It’s a compact mountain ash with a tidy, narrow form that works well in limited spaces, showing flowers and fruit without overwhelming the landscape.
It grows up to about 20 feet tall with a spread around 8 feet. The canopy remains relatively short and oval, with stout branches that hold up well over time.
White flowers in spring produce orange then red fruit, and the green compound leaves turn yellow in fall, creating a bright, seasonal display.
It tolerates compact spaces, small sidewalk openings, drought, and minimal maintenance, making it a reliable choice for urban planting.
Minimal pruning is needed once established. Birds often eat the fruit before it falls, and the tree maintains its tidy, upright form with little intervention.