UNITED STATES—Most vegetation within home gardens is better than it was naturally in the wild. For many, systematic selection isolated the best from average populations. Selective breeding and hybridization improved many others. Some are too genetically compromised by breeding to produce viable seed. Feral progeny of those that are not demonstrate the divergences.
Such feral progeny are generally not true to type. They are, to varying degrees, more like their ancestors than their direct parents. Some can revert directly to a natural state in the first generation. Some do so slower through a few generations. Feral progeny of hybrids are still hybrids but may be more primitive. Many hybrids produce no viable seed though.
‘Jewel Mix’ nasturtium, for example, blooms with many shades of yellow, orange and red. Several are pastels. Some are dark enough to be almost brown. A few are bicolors. Their progeny though, blooms with less light, dark and red colors. Bloom becomes exclusively bright yellow and orange as feral plants replace originals. It reverts to more natural color.
Improvement is debatable.
That is because nature is efficient. By human standards, innately unnatural breeding and selection improve plant life. They produce better fruits, vegetables, flowers and anything that grows on plants. However, they interfere with natural functions such as reproduction. Seedless limes, which are preferable within home gardens, would go extinct in the wild.
Plants that revert to more natural feral states are merely trying to survive. Sterile pampas grass is only sterile because it is exclusively female. Naturalized Andean pampas grass can pollinate it from a distance, though. Their hybrid but nonsterile feral progeny may be as invasive as their Andean parent. They are detrimental to their ecosystem but survive.
Not all feral flora grows from seed. Seedless and thornless honeylocust are grafted onto wild honeylocust understock. Seedy and thorny suckers can grow from such understock below its grafts. They commonly develop after removal of original grafted trees. By some standards, they become aggressively invasive. By other standards, they are sustainable.
Highlight: Nasturtium
Most consider nasturtium, Tropaeolum majus, to be a warm season annual. Some might consider it to be a cool season annual. A few press its tender stems into moist soil to root and continue growth as a perennial. Plants that bloom for summer can disperse seed for winter bloom. Plants that bloom for winter can likewise disperse seed for summer bloom.
Because they replace themselves so readily, they may seem to be perennial. In actuality, plants from one season, whether warm or cool, may not last long in the next. Seed might be sneaky about spreading. Trailing nasturtiums might naturalize in riparian ecosystems. Nasturtium seedlings are available in cell packs, but do not grow as vigorously as seed.
Nasturtium bloom is diverse shades and tints of yellow, orange and red. Varieties bloom with particular colors within that range, although few are true to type. Their feral progeny bloom only bright orange and bright yellow. Their tender growth does not get much more than one or two feet deep. Trailing varieties can climb as high as first floor eaves though. Nasturtium leaves are almost circular like those of water lilies.
Tony Tomeo can be contacted at tonytomeo.com.
