In “Thugs in the Garden” (KL, Summer 2015) I wrote about plants that overtake a border by intensive root systems or by self seeding. Part of an education of a gardener includes figuring out which plants are aggressive and which ones are well behaved. I have been gardening in the same location for 13 years and a list has emerged of plants that know how to have a conversation with the plants next to them. It has taken me a while to figure this out because in a young garden there tends to be plenty of space for plants to grow and fill in. I have been an impulsive buyer of plants. Many of the most aggressive plants behaved perfectly well for the first five to seven years, but once the plants grew into each other all sorts of things start to happen. For years I got along by thinking they will work it out amongst themselves. But after several recent bouts of removing some of these aggressive plants, I realized that it’s not a good idea to put off editing a garden. The longer you avoid these problems the harder the choices are, and the physical work of removing plants gets more labor intensive with each passing year.
Naively, I once believed that a mature garden would be easier to work in than a young garden. But a more established garden is like an old body: it requires more checkups, attention to detail, and tweaking. The knee that worked fine in my youth, can suddenly becoming wobbly overnight. The muscles that hold the knee in place need to be strengthened. An older garden requires the same sort of attention. Plants age and can outgrow their allotted space. We need to make decisions about how to create a pleasing balance so the whole garden doesn’t go to hell in a hand basket. Do I shape the shrub to let in light and leave space for the tree peony? Or do I let the shrub grow to its mature height, choking the peony of all light? Or do I risk killing the tree peony by transplanting it to another area? Our designs need to change as plants fulfill their natural shapes and sizes. Change requires us to give up some of our initial intentions and this can be painful.
Last year, I removed several large clumps of phlox- ‘David’ from several borders. The white flowering phlox had grown so large that a once colorful border had turned into a white garden. By removing the clumps I allowed other plants room to grow into the new space; but in other areas I was left with huge holes. I decided to fill in these gaps with native species, shrubs or well behaved perennials. It will take me several years to get rid of each of the aggressive plants, but I have a plan and clear idea of how to proceed.
Hybrids and variegated plants tend to be weaker plants and so are less likely to spread. Some species seem to be more aggressive such as Astrantia ‘major’, is a meadow plant in Europe. The hybrids- Astrantia ‘Ruby’s wedding’ and A. ‘Roma’ behave very well, but do not bloom as long, nor do they spread all over the garden. A friend grows Echinacea ‘purpurea’- (the native) in her garden and it has self seeded all over the place. I grow the hybrid Echinacea ‘White swan’ and it has hardly moved at all.
After compiling the list of plants that behave in my garden I Googled “well -behaved perennials” and the list I found online was identical in terms of species. I wish I had thought to do this when I laid out my garden. Gardening, like life, is about constant change and loss. Reacting to the present reality, while difficult, is a whole lot easier than trying to hold onto what was. I have found being present in the garden and meeting those necessary changes, while challenging, is the only way to keep my garden vibrant and myself engaged. I hope the list below provides a good starting point for plants that do know the art of conversation.
Well Behaved Perennials:
Early Spring May- June
Dicentra exima or spectablis Alba – bleeding heart
Papavar Oriental cultivars- Oriental poppies,
Mid Summer June- July
Geranium ‘Ballerina, G.Rozanne, G.Dragon Heart, and G.Johnson’s Blue
Veronica Blue carpet,
Nepeta ‘Dropmore blue’, N. ‘Walker’s Low’, N. ‘Sixhills Giant’
Iris siberica- Siberian Iris
Echinops ritro -Globe thistle
Late Summer August- September