Cedar apple rust/ Hawthrown apple rust - Ask Extension
Hi there,
I am a Landscape architect working on a project on the Front Range (Greeley CO). I am hoping to include disease resistant crabapples, Ame...
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Cedar apple rust/ Hawthrown apple rust #922758
Asked December 09, 2025, 9:45 AM EST
Hi there,
I am a Landscape architect working on a project on the Front Range (Greeley CO). I am hoping to include disease resistant crabapples, Amelanchier (Malus x Indian Summer, x Radiant) and Craetagus ambigua in our design. I have been made aware there will be native Juniperus scopulorum, Juniperus osteosperma in adjacent lots and design areas within a 1 mile radius. Knowing native junipers are a host species for CAR, how resistant are the above mentioned selections? We have no desire to have fruit production, all our Apple/Rose/Hawthorn species are for ornamental purposes.
Is it better to avoid using these altogether and specifying different ornamental trees? Or will these CAR resistant species appropriate even when in close proximity to native Juniperus host species?
Weld County Colorado
Expert Response
Hi Stefan,
Both would be good options to avoiding rust. While I am less familiar with the Malus X indian Summer cross with Radiant--both have good resistance (https://trees.umn.edu/crabapple-malus-spp , https://extension.psu.edu/theres-a-flowering-crabapple-for-that)
In general Crataegus spp. tend to have excellent resistance (https://ecommons.cornell.edu/server/api/core/bitstreams/565fe493-a2c5-4e3a-b559-084019c2f3a4/content , https://www.gjcity.org/727/45-Russian-Hawthorn)
Hope this helps!
