In order to help them survive, humans throughout the ages have carefully manipulated plants in order to propagate desirable traits. Ancient cultures in central Mexico transformed small tufted grasses into what we now know as corn, and the Romans worked tirelessly to create the perfect rose.
Profound changes to these species were wrought through cultivation, wherein the intrepid grower would select plants with certain qualities and breed them together to hopefully ensure offspring with similar traits.
This ancient practice still continues to this day, and in fact a large percentage of the plants we eat are specific cultivated varieties- or cultivars- of plants that look very different from their ancestors.
Many commonly sold plant varieties have been designed to dazzle human visitors yet offer very little food, shelter, or nesting sites for wildlife. This can be due to the fact that some cultivars rely on strange mutations in order to accomplish their end goal. Take, for instance, the ‘double flower’ or ‘double bloom’ variety seen commonly in roses, lilacs, peonies and others. Plants of this cultivar are immediately stunning to the eye- their flowers are packed with twice the amount of petals as normal, and seem to almost burst at the seams.
This beauty is purely superficial, however, as these added petals are actually mutations of the reproductive structures of the flower itself. This means that while there are larger flowers, any animal visitors looking for nectar or pollen will find their efforts fruitless and a waste of valuable energy, as little to no pollen is available and the crowd of petals makes nectar collection difficult.
Other plant varieties alter leaf colorations in order to suit the taste of gardeners, but these too can come at a price. Leaf color is usually determined by the chemicals in said leaf, and many of these chemicals also serve to ward off other creatures.
Animals reacting with a plant that has altered leaf colors can sometimes come into contact with chemicals that they were not prepared to deal with. In many instances insects are the ones that feel the brunt of these changes, and whole populations are lost when their naturally preferred plants are replaced by poisonous ones overnight.
The practice of cultivating specific varieties is not purely for aesthetic purposes, however, and there are varieties bred in order to be more resilient to environmental stressors. This can make restoring natural landscapes easier in areas that have been deeply disturbed by human development or natural disasters.
Many cultivars currently on the market are weaker to environmental stressors than their unchanged counterparts. This is because current horticultural trends rely on cloning in order to propagate desirable qualities once they are found.
This practice can lead to those new plants having less genetic diversity between themselves. Less genetic diversity means that it is easier for a pest or disease to take advantage of a shared weakness in the species. There are varieties being bred to become more resistant to pests and diseases as well, however, so some of these weaknesses may soon be mitigated.
While not all cultivars are as harmful to wildlife as those that impact bloom type or foliage color, it is a good idea to diversify your plantings – try and plant unchanged species wherever possible as well. In most cases, the unchanged version is tougher and far more beneficial to the environment than cultivars of the same species.
The effects that cultivars have on the wildlife around them is a bustling field at the moment, perhaps soon even leading to varieties of plants that are resilient to pests and diseases while also having little or no negative impact on the world around them.
Brannen Basham and his wife, Jill Jacobs, operate Spriggly’s Beescaping, a business dedicated to the preservation of pollinators. Contact him at firstname.lastname@example.org.