It would take many lifetimes to exhaust all the possibilities of plant selection and design options for our gardens. Take kinetic plants, for example. These are species that sway in the wind or even in a mild breeze. They include ornamental grasses, sedges, and rushes. Butterfly bushes (Buddleja spp.) and wand flowers (Gaura/Oenothera linheimeri) possess this quality as well. Many are extremely drought tolerant while others can live on the edge of a pond and yet, planted in the garden, may require only occasional summer water.
San Marcos Growers lists 91 different types of ornamental grasses alone and Monrovia Nursery lists 156 options (monrovia.com/shop/by-type/grasses.html) under what they broadly classify as grasses. The reason for Monrovia’s more extensive list is that bamboos, which are members of the grass family, and sedges and rushes which are not grasses but resemble them in certain respects, make Monrovia’s list, as do mondo grass and liriope, which actually belong to the lily family.
There is one common denominator to the diverse plant groups found on the Monrovia list referenced above. They are all monocots. Flowering plants or angiosperms are divided into dicots and monocots. Dicots have two seed leaves or cotyledons and monocots have one. The two halves of a kidney bean are known as seed leaves, the first “leaves” to show themselves when the seed germinates. A corn kernel, by contrast, or a palm tree seed, when planted, reveals a single slender seed leaf upon germination. You might think that monocots would be a more primitive life form than dicots. After all, isn’t a rose, a notable dicot, a more complex flower than a cornflower, whether a corn’s male tassel or female silk is concerned? And don’t we typically associate complexity with more advanced evolutionary plants and animals? This was the accepted theory regarding which came first – the monocot or the dicot – until the late 19th century.
For more than a century, however, the dominant theory to emerge on this subject maintains that monocots evolved from dicots. Most recently, DNA sequencing has given this theory greater credibility. Also, when it comes to resilience and persistence, qualities that determine fitness and therefore more advanced and sophisticated development in evolutionary terms, monocots outshine dicots. Grasses are found on 20% of the earth’s land mass, much of this in areas where nothing else will grow. Having only one cotyledon, the embryo – which consists of a rudimentary root and first true leaf – of a monocot obtains all its sustenance from a single source whereas a dicot embryo must have two cotyledons fully functioning to sustain its embryonic growth. Monocotyledons such as grasses also grow rapidly and quickly form flowers whereas many dicots must first produce wood and may grow for several years before flowering. Monocots are also tougher than dicots in showing a greater capacity to regrow after being burned or grazed, in addition to being resistant to diseases and insect pests. I must say that, having observed a wide variety of ornamental grasses for decades, I have never noticed any signs of disease or insect damage among them.
Getting back to kinetic plants, I decided to write about them after receiving the following email from Donna Pullman, who gardens in Seal Beach. “I live sort of near the beach and have a spot by the sidewalk to plant in front of a picket fence. I really need to simplify my life with low-maintenance plants. I would love something that can blow in the breeze and have some movement. I like the Mexican feather grass but am thinking it’s maybe not good for our environment. Thank you for any advice.”
I remember the first time I saw Mexican feather grass (Nassella tenuissima) years ago and recognized it as one of the most beautiful plants under the sun. It’s a clumping grass with delicate tresses of green that become blonde and then tawny gold as they mature. What’s more, Mexican feather grass self-sows with alacrity and will soon take over a sidewalk planter, needing only a modicum of moisture to thrive, to say nothing of its swaying back and forth in the gentlest breeze.
The problem with Mexican feather grass, as Ms. Pullman hints, is that it knows no boundaries. Within a few years, it could easily take over your garden and adjacent gardens in your neighborhood as well and eventually spread into the surrounding hills and canyons, choking off native flora. Most nurseries no longer sell this plant because of its invasive tendencies.
Furthermore, when it comes to low-maintenance plants, I would not necessarily place ornamental grasses in this category. Aside from the fact that some of them spread, if not as wildly as Mexican feather grass, even many of the tamer grasses need to be manicured once a year in order not to end up looking ragged. It’s recommended that the popular burgundy fountain grass (Pennisetum setaceum var. Rubrum), for instance, which is sterile and does not self-sow, is best cut back once a year. The pruning procedure may be carried out at any time from late fall to early spring. Trim down so that one-third of each clump remains. If you cut back too far, they may not regrow. Once the clump starts sending up new growth, you can divide it and plant the divisions in other parts of the garden. Make sure you divide when plants are actively growing and before winter comes. Otherwise, your divisions may languish and even die after being transplanted.
Incidentally, there is an ornamental grass that does self-sow but not so aggressively and it is sometimes suggested as a lawn substitute. The species in question is blue oat grass (Helictotrichon sempervirens). There are two types of lawn substitutes, both of which, by definition, are drought tolerant: those that function as lawns, meaning they can accept foot traffic to one degree or another, and those that simply cover the space that a lawn would otherwise occupy. Blue oat grass is of the second type. I once planted it and witnessed it slowly but surely taking over space that once was lawn but had since been turned into perennial beds. I removed most of it but can vouch for its charms. It does not require yearly pruning like fountain grass to keep its fresh countenance and fountainesque shape.
If you do decide to go with grasses, you might contrast burgundy fountain grass with blue oat grass, blue rye grass (Leymus arenarius ‘Glaucus’) or blue moor grass (Sesleria caerulea). Variegated grasses are also popular, with white- and yellow-striped zebra grasses (Miscanthus varieties), and variegated reed grass (Calamagrostis x acutiflora ‘Overdam’)leading the way.
Two pink flowered grasses come to mind and they would also contrast well with the blue and burgundy species mentioned above. One of them is widely considered to have the most beautiful flower tassels of all ornamental grasses. Known as ruby grass (Melinus nerviglumis), it blooms in the hottest summer weather when it displays spellbinding pink inflorescences that turn an attractive burgundy bronze. Photos never do justice to ruby grass, imparting but a small measure of its essential beauty. Pink hair or pink muhly (Muhlenbergia capillaris) is fully capable of surviving a drought, although it looks better when soaked on an occasional basis as it is transformed into a fluffy cloud of pink.
Then there are the demonstrably kinetic rushes, including the California gray rush (Juncus patens), with strong cylindrical stems to two feet high. My favorite rush, native to South Africa, has a feature that, to the best of my knowledge, is not found on any other plant. Brown bands on its cylindrical stems turn to gold on the inside before sloughing off; it is as if you are looking at peeling, 22-karat gold leaf strips each time you walk by the plant. Eventually, attractive brown flowers form on stem tips. This plant goes by the name of cape rush, and comes in two sizes, one with three-foot stems (Chondropetalum tectorum) and one with stems reaching up to five feet or more (Chondropetalum elephatinum). Both ornamental grasses and rushes make excellent container specimens.
As mentioned earlier, butterfly bush is a kinetic plant, and a highly desirable one at that, especially now when its flower clusters in lilac or purple expand to a length of 12 inches or more. You never have to prune it but for larger flower clusters and a more compact plant, you will want to prune it back by two-thirds every now and then; just before the growing season begins is the time to do it. Wand flower, also referred to as gaura or whirling butterflies, sends up two-foot shoots studded with white or magenta pink blooms all summer long.
If you have had success with a kinetic plant (or plants), please share your story by sending it to the email address below. You are invited to send questions, comments, or photos to [email protected]