Cornus Florida

Asked March 20, 2013, 10:37 PM EDT

I'm an experienced gardener (Master Gardener, botanical garden experience etc.) and I love dogwood but now I live in Colorado. I keep picking up hits that there are a few in Denver, one in someones yard in Boulder, one in Longmont on the Fair Grounds etc. Anyway, I want to try one here in a protected spot, moister than most, in Boulder. I've found mildew and acthracnose resistant varieties. Am sure mildew is not a problem here but do you have any thoughts about dogwood acthracnose? My suspicion is that there are so few dogwoods here it wouldn't be a problem but I realize any dogwood (cornus florida) will find itself in "foreign" territory and want to give it all the help and protection it needs. All must be shipped and I've found sources in Tennessee. Should I pay extra for the anthracnose resistance (Cornus Florida v. Appalachian Spring)? Any other thoughts?

Boulder County Colorado trees and shrubs master gardener program horticulture

1 Response

There probably are a few flowering dogwoods scattered around Denver/Boulder. But it's likely that not all of them are thriving. Flowering dogwood needs well-drained acidic soils with high organic matter content. Most Front Range Colorado soils are clayey with less pore space and not as well-drained as C. florida would prefer. Most Front Range soils - unless they have been cultivated and irrigated for many years - are alkaline, with pH ranging from 7.2 - 8.2 Most Front Range soils have low organic matter levels, often less than 1 %.

Powdery mildew is a problem on certain plants in Colorado; see http://www.ext.colostate.edu/pubs/garden/02902.html

You can see that it will be a challenge to grow one in your location, but at least a protected spot is a start.
Suggestions:
-have a soil test done to learn organic matter, pH and lime levels. http://www.soiltestinglab.colostate.edu/
-since C florida has borderline winter hardiness for our area, suggest you look at shipping one from a more northern nursery or choosing a variety known to have better winter hardiness. It won't hurt if that variety is anthracnose and mildew resistant.
-consider settling for C. controversa 'June Snow' which is better-adapted to Front Range climate and soil conditions.
- see also:
http://www.ext.colostate.edu/pubs/garden/07220.html
http://www.ext.colostate.edu/pubs/garden/07235.html

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