Too Good to be True Perennials

I get asked a lot by clients to include long flowering, colorful, and unique perennials in their designs. When a new perennial comes out on the market claiming to be one or more of these, I always proceed with caution.  I’ve been disappointed before. Here are a few perennials that fell flat and a couple tried and true perennials that can’t be beat.

1.  Limerock Ruby Coreopsis. This was a true red flowering lace-leaf coreopsis introduced about 12 years ago. It seemed cold hearty for Zone 5, but was originally tested on sandy soil, not clay, which is found over much of the midwest. It is now considered a tender perennial in the Chicagoland area, which means that in mild winters they will often survive, but in typical seasons may not.  Try Moonbeam or Zagreb Coreopsis for a light and dark yellow option of this perennial that has proven cold hardiness. I prefer it in an informal setting like a back border or cottage garden because it re-seeds freely.

2.  Frosty Morn Sedum. I point this one out to explain the caution using any variegated plants. I had purchased Frosty Morn Sedum for my parents yard years ago before I knew better. Slowly non-variegated stems began to grow in with the white tipped leaves of the variegated stems. After a season or two the plant had reverted back to the parent plant. This is very common with variegated plants. They are essentially mutants that are bred for their unique characteristics, but thus are unstable.  The tried and true version is called Autumn Joy Sedum. For a darker flower that has shown hardiness try Autumn Fire Sedum.

3. Sunset Coneflower. One of the first orange coneflowers is fairly unstable and the seeds produced by the plant will yield purple flowers, not orange. The Chicago Botanic Garden has introduced the Meadowbrite series, which show promise. Coneflowers have been in the spotlight for interesting cultivars like Double Decker which has flower petals on the top and bottom of the cone and a host of others. I have proceeded with caution on planting thus far and stuck with Magnus,  or Kim’s Knee High.

4.  Butterfly Blue Scabiosa. This one isn’t a total flop, but I’ve tried it many times and have had issues with powdery mildew. My guess is that clay soil is a contributing factor in preventing the plant from drying out quickly between waterings. This variety was grown for its compact size and blue flowers. I would prefer to get blue flower color using Catmint. I use Walker’s Low for spots that can handle the spreading habit. I have been using Kit Kat for a few years for areas that cannot handle the spreading habit, but it isn’t as floriferous.

5.  Dwarf Fountain Grass. This is a perennial I have seen do very well in some locations. Often the straight species does the best and if I do plant it, that is the one I try to stick with. As with many of the other plants I’ve found to not be hardy, the problem seems to lie in the soil. Hameln, Little Bunny and Little Honey are all varieties that have not survived over the winter. However,  the worst survival rates, we found, were in the new subdivisions where much of the soil is disturbed or lacking.  At homes with a lot of topsoil, the survival rate was better. I have been on a quest to find a compact ornamental grass that my clients have liked equally as well as Fountain Grass and so far haven’t been greatly successful. I substitute Prairie Dropseed for compact clump forming grasses and have tried Tufted Hair Grass, though it needs a special location because the seed heads grow very tall and the grass foliage is very low.

Also some newer varieties or rediscovered perennials I am in love with right now are Summer Beauty Allium, Amsonia ‘Ice Blue’, Heuchera ‘Obsidian, and Stachys ‘Hummelo’ to name a few.

Any stories of your favorites tried and trues or disappointments? I’d love to hear about it.


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