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.
gardeninacity 
Excellent advice — thank you for pointing out this resource! Hard to believe but so true that soon we’ll all be studying and selecting plants for the new season. I’m going to check out the hardy geraniums’ rankings, which should prove helpful IF I can identify the many varieties planted here before we arrived!
That can be tough. Many of the varieties look pretty similar.
Thank you Jason for this idea. I’ve never read the the Chicago Botanic Garden’s Plant catalog and the next spring I should do. I think our climate is a bit similar.
Your at a more northern latitude, I think your winter is longer. But we both have cold winters and hot summers.
Thanks for the link and info, Jason. I have a couple kinds of bee balm, but until I saw your photo, I had not thought of mixing them in the same planting. Duh!
Some things seem obvious only after they are right in front of you. i’ve had the same experience.
Good to know! We have a number of excellent plant trials in our region, with University of Georgia, University of Tennessee, and University of NC among the best, but I don’t know of a comprehensive study such as CBGs.
How are those University plant trials different from CBG’s?
Thank you for the tip. 🙂
You’re welciome.
Thanks, Jason. I have seen results of several of their trials in Fine Gardening. What we really need is a Craig’s List sort of thing for plants.Of course, that means one for your ecozone, and one for my ecozone. and one for ……. It does get complicated, doesn’t it?
It does, and even in the Upper Midwest conditions can vary considerably, so that no evaluation is really fool proof.
And the award for the most prolific garden blogger goes to…GIAC. Man,seems like you’re popping up in my mailbox with great posts like this every few days. Will be sure to check out this resource, my friend.
I aim for every other day, actually. But I know people who post every day.
I have been growing Geranium ‘Brookside’ for years but then my name is Brook! It flowers so much longer than the basic form.
Great to have powdery mildew advice on Monardas. If you get the wrong ones on my sandy soil they are a complete mess with this disease
I have heard other gardeners speak highly of ‘Brookside’.
Sounds like a great resource. Will be useful for those that garden in the Midwest. Although I am not too familiar with the trials that the RHS do over here, I’m sure they don’t give them a points rating but when we see the words RHS AGM on the label, then we know it should a worthy plant for the garden.
We have an American Horticultural Society but it is not nearly as well known as the RHS.
Great Plant Picks is our go-to resource for plants that do well here. It’s valuable but often ignored: we do suffer from our share of zonal denial, after all. Sounds like your experience is bearing out CBG’s conclusions.
I tend to be cautious about using plants that are marginally hardy, too timid for zonal denial.
I pay lots of attention to those plant trials. Monarda is a hot mess when it’s mildewy so I have lots of Raspberry Wine, too. But in my humidity, every variety ends up with at least some mildew so I’ve just have to learn to deal with it. But some times I just have to plant a few different cultivars that are reported to be mildew resistant and see what does the best for me. But I do avoid the ones known to be mildew magnets.
I have the same attitude. I try to stick with varieties that have good resistance but some time before the end of August they all have mildew. I just accept it.
Resources like that can be very valuable!
Exactly.
That looks like a great resource, even for people in other parts of the country! I’m not surprised that Raspberry Wine scored well; I have a lot of it too. It looks great in your garden with the wild bergamot.
I would have liked to see the species Geranium maculatum evaluated too, just out of curiosity. I love it.
It’s funny but they did test the straight species wild bergamot and found its performance poor, which has not been my experience.
Reblogged this on Rhymes with Linnaeus and commented:
Here’s a handy post from the Garden In A City blog about the Chicago Botanic Garden Plant Evaluation Program. Since Southern Ontario shares the same ecoregion as the Chicago area, you’re safe to assume that the information works well for us, too. Now finding the top performing plants for your garden is just a click away. Enjoy the read!
Thanks for reblogging!
Thanks for the info: I will definitely check it out! It may not apply directly to me up here in Wisconsin, but I’m close. And it seems we have similar garden conditions, except that I have more shade and less sun than you do. I only have the straight species of Geranium maculatum in my garden–it grows prolifically here with plentiful blooms! The pollinators (and the people) love it!
I think you’ll enjoy them. For one thing, I was amazed at all the varieties I had never heard of.
I’ll check out this resource. When I first started gardening I kept seeing ‘Johnson’s Blue’ as a must-have plant but have never been able to keep it going.
I’m keeping my ‘Johnson’s Blue’, it’s quite floriferous and I like its habit.
UMMMM….how cool is this!!!! I am jumping on over right now!!! Thank you for passing this one along friend! Hope you have a wonderful vacation with your family! Nicole
Happy Holidays, Nicole!
What a great idea – wish there’d be something like this around here but often when I read American garden books (and English ones of course) I can’t help but think we have a lot to learn still.
I have the impression you have much milder weather than we do here.
where I am now yes but before winters were tough and long
That does sound like a helpful resource! I must see if we have anything like that……oh….roll on spring!xxx
Maybe the RHS?
That is a great service to the community. I cannot even guess at how much money I have spend on dud plants — the ones that catalogues hype but never seem to perform well. The federal government used to sponsor agricutural schools across the country to do this kind of thing — test varieties of crop and ormanmental plants to see what grows well regionally. It is really a crime that those programs have withered.
The same thing has happened to so many public services provided for the common good.
Plant trials are in Buffalo also. I do believe gardeners should pay attention to what grows in their locale rather than advice given from other parts of the country. Growing conditions (mostly soil, but also air with salt or excess wind as examples) can vary greatly even in short distances from the home garden.
It’s tricky because there are variations even within a region – areas of clay and sandy soil, for instance.
Thanks for the advice, Jason. I get emails from the Chicago Botanic Garden, but I’ve never really checked out their plant trials. For general info, I often go to the Missouri Botanic Garden’s website, which is also very helpful. One of our local MG’s sends out the results each year of trial plants in our Idea Garden, and I’ve come to depend on that a lot for picking out annuals each season. Whatever the source, I’ve learned that local or regional trials really are the best for judging whether a plant will do well in my garden, not the plant catalogs!
I am always looking for great evaluations of cultivars so am bookmarking this…thanks Jason!
Great information as usual. Delighted to find out about the CBG plant site. Grew up in Evanston, IL. but now garden in North Carolina. But! I’ve got a grown daughter with her first home and garden in Chicago suburbs. She will love this post, which I will forward to her. This is always a well done blog deserving kudos.
Jason, Thanks for sharing this resource. I clicked over to the CBG site and immediately confirmed my ‘plant nerd’ credentials by getting totally lost in the reports.