Help for Midwest Gardeners: How Do I Choose the Right Plant?
Let’s say you’ve decided you want to plant Bee Balm (Monarda didyma). You go to an online catalog, and there could be dozens of varieties to choose from. How do you know which is best? You can go by the description in the catalog, which may be more or less accurate. This may purport to tell you the size or color of a variety, but won’t tell you much about how a specific variety performs in your region.
That’s where the Chicago Botanic Garden’s Plant Evaluation Program comes in. CBG tests the garden performance of large numbers of varieties and species for selected genera. So far they have produced 37 reports, all of which can be downloaded for free from their website. To visit their website, click here.
Many more are in the pipeline. Before evaluations are completed, however, perennials are tested for four years, shrubs and vines for six, and trees for seven to ten.
Of course, performance depends in part on local conditions, and different varieties of the same species may be best suited to different environments. These evaluations, then, are most relevant to gardeners in the upper midwest. Still, gardeners elsewhere may want to take note.
This is especially true because these reports are a delight for obsessive plant nerds.
For example, the report on Monarda and mildew resistance evaluated 39 Monarda varieties. And the folks at CBG Plant Evaluation are tough judges. Plants are rated on a one to five star scale, and none of the varieties got all five stars. Only two – ‘Raspberry Wine’ and ‘Marshall’s Delight’ – got 4.5 stars (I have lots of ‘Raspberry Wine’.).
I was especially interested in the report on Hardy Geraniums. The report evaluated 97 varieties derived from 17 species. Again, none of the varieties earned a perfect five star rating. Only six varieties got 4.5 stars. The only one of those six I was familiar with was ‘Brookside’.
And 14 of the varieties flunked out completely, including ‘Bressingham Pink’.
I was interested to see how the Hardy Geraniums in my garden fared in the report. ‘Johnson’s Blue’ got 3.5 stars, just fair to good. I was a little offended on JB’s behalf, as I had always found him to be a strong perfomer. ‘Biokovo’ got four stars (good), which is consistent with my experience. And ‘Tschelda’ (Geranium renardii) got just two stars (poor). This sadly confirms my own observations, mainly due to ‘Tschelda’s’ scarcity of flowers.
I have lots of the wild Geranium maculatum, but unfortunately the straight species was not evaluated.
Before you know it the holidays will be over and it will be time to start pouring over plant catalogs. When you do, you might want to peruse the Chicago Botanic Garden’s Plant Evaluation website for backup.