Avant Gardening

This Spring Let Us Do The Switcheroo!

Native Alternatives to Invasive Plants

Many of the once ‘beloved’ ornamental horticulture plants are beginning to take advantage of our admiration for them… Recent studies have found that these plants are escaping from our well-manicured flower beds and reverting to their rebellious ways, scattering themselves throughout our natural ecosystems and displacing our native species.

The next couple blog posts will discuss plants that are currently on the Wisconsin Department of Natural Resources Non-Restricted or Caution lists. According to the WI-DNR “Non-Restricted” means that the species ‘…may have some beneficial uses as well as negative impacts on the environment but are already integrated into Wisconsin’s ecosystems so that control or eradication is not practical or feasible. Not proposed to be regulated at this time.’

Some of these plants are grown commercial and thus would cause economic hardship to those who sell it – as you can imagine this makes ‘blanket’ regulating more challenging, for instance proposed regulation allows for a phasing period in which their current stocks can be diminished. The plants listed below are still readily available and sold in nurseries, both as wholesale products to landscapers and in retail settings to the general public – BUT think twice before you buy!Amelanchier 'Coles Select'Serviceberry (Amelanchier x grandiflora) vs. Callery Pear (Pyrus calleryana)

Surprisingly, Callery Pear has actually been imported multiple times to the U.S. starting in 1909 to the Arnold Arboretum. The U.S. Department of Agriculture used it for the development of a fire blight resistant common pear and it was widely planted as a rootstock originally. Around 1950, the ornamental value and urban tolerance of Callery Pear was recognized and lead to the creation of the widely planted cultivar ‘Bradford’.

Nps.gov summaries the potential threat best, ‘While some genotypes are self-incompatible, meaning they require cross pollination from another genotype in order to set seed, others can pollinate themselves. Different genotypes growing near each other (e.g., within about 300 ft.) can cross-pollinate and produce fruit with viable seed. Also, cultivars are often grafted onto seed-grown rootstocks with varying genotypes; if the plant produces shoots from the rootstock (which it often does), then these shoots and the graft can pollinate one another. Thus, the Bradford pear cultivar is one of several cultivars (varieties) of Callery pear capable of spreading and being invasive.’

In Illinois, it isn’t hard to find Callery Pear escapees in lawns, fencerows, and disturbed wooded areas. Wisconsin is a little more protected from this species invasion because the plant was originally borderline hardy, but since cold hardy cultivars have been developed the threat is on our doorstep. Not to mention our changing climate and increasingly less harsh Wisconsin winters…20160323_083820

Serviceberry is an EXCELLENT native alternative! The cultivar ‘Autumn Brilliance’ can be purchased as a single stem small ornamental tree in the same height range as Callery Pear, but with better branching structure. Observations of Amelanchier spp. phenology can provide valuable information. For example, they are some of the first trees to break bud in springtime, which reflects warming soil temperatures and possible times for planting. They can also be a good indicator species of drought, when it becomes too dry their leaves begin to curl inward.

During springtime there is a profusion of white flowers, that give way to edible blueberry-sized, red/purple berries that are delicious! Some people describe them as a mix between an apple/raspberry/blueberry! Great red-orange fall color later in the season rounds out this multi-seasonal beauty.

Stay tuned for more easy plant switcheroo’s in the upcoming weeks!