There is no doubt about it: weeds are sustainable. Otherwise, they would not be weeds. By definition, they grow where they are undesirable. Less sustainable vegetation should be less invasive. Also, it should be less resistant to eradication than most familiar weeds are. Unfortunately, also by definition, weeds are undesirable. They can not become fads.
Sustainable horticulture is a fad, though. Unlike most fads, it is actually quite sensible. In theory, it is horticulture that requires as minimal intervention as possible. It excludes that which requires intensive or impractical cultivation. For example, native species that grow wild are sustainable. Tropical species that may survive only within greenhouses are not.
A problem with the sustainability fad is its marketability. “Sustainable” and “Sustainability” have become cliche buzzwords. They too often describe merchandise that is contrary to the fad. Realistically, genuine sustainability is unsustainable within profitable marketing. Truly sustainable merchandise would eliminate most of the need to ever purchase more.
Modern cultivars can qualify as “new and improved” as they first become available. They are certainly new. However, their improvements may be questionable. Hybridization and extensive breeding can cause genetic deficiency. Even natural variegation compromises vigor. Seed is not true to type. Most aesthetic improvements are contrary to sustainability.
Native species are technically sustainable. Once established, they might survive without irrigation or other attention. Unfortunately though, some are not very adaptable to refined home gardens. Some are vulnerable to rot if nearby vegetation needs frequent irrigation. Some perform vigorously only for a few years. Several species are innately combustible.
Ironically, several of the most passe and old fashioned species are the most sustainable. That is why some of them became passe. Lily of the Nile can survive indefinitely. If it gets overgrown, it is easy to divide and relocate. It may be available for free from neighbors or friends. African iris, New Zealand flax, bergenia, most aloe and many yucca are similarly sustainable.
Highlight: cardinal flower
This warm season annual is actually a biennial. Cardinal flower, Lobelia cardinalis, may stay relatively short for its first summer. It might bloom four feet high for its second or third summer. By then, pups are easy to divide as new plants to replace the old. Most cardinal flower plants from nurseries are rather mature. They might grow tall for their first summer.
Common cardinal flower has rich cardinal red bloom and bright green foliage. “Alba” has white bloom. “Rosea” has pink bloom. “Queen Victoria” has familiar rich red bloom above deeply bronzed foliage. Individual flowers are only an inch-and-a-half from top to bottom, but are numerous. Basal leaves can be almost six inches long.
Upper leaves are shorter.Cardinal flower enjoys richly organic soil with regular irrigation. It dislikes getting too dry. It appreciates a bit of partial shade as the weather gets warmest after noon. Seed is easy to collect. However, seed from fancy cultivars is not necessarily true to type. Subsequent generations eventually revert to familiar rich cardinal red bloom and bright green foliage.
Tony Tomeo can be contacted at tonytomeo.com.