Do you like the way I bloom?
Many don’t like the Callery Pears for a variety of reasons.
Being a non-native tree, many frown on seeing them so commonly used in gardens and on city streets. Good news for those disapproving of the Callery Pears is that they are short-lived trees. Most live only 20 years, at most about 30 years. Some decline of “old age” or disease (Redspire is susceptible to fire blight), where others succumb to wind damage.
Another common complaint is that the flowers have an offensive odor. It is not a cutting you want to force inside for an early flower show. Outside, I never really notice the smell. Funny thing about this odor. The volatile compounds in the Callery Pear are suspected to be attractants, and not necessarily an odor to repel pollinators. Shown in this post is the Redspire pear.
The ornamental pear is a tree that will provide food to pollinators when other plants may have yet to bloom. Many early bees, like honeybees will be seen gathering food. In late winter, the small fruit is a godsend to many birds like robins and blue jays having trouble finding berries, the preferred food plants being stripped by late fall. Yes, there are good points to this tree.
Besides just being pretty.
Ornamental pear should not be planted in most places in this country because it does invade forests perimeters. It is still undetermined to what extent how detrimental they have become.
While many of the pears were bred to be sterile, and cultivars each were propagated by cloning, each individual being genetically identical. The Callery pear is self-incompatible and can not pollinate itself to produce fruit. The problem is that each of the subsequent cultivars is genetically different from the other cultivars, which means they can cross-pollinate with each other to produce fruit. This is how they are showing up as understory trees at forest edges. New crossed-trees are being created.
So how does this fit in with a warming climate? Where our cold climate has not had the ill effects of the pears invading forests, the changing climate may allow plants that did not cause harm to get a foothold where they just might. For non-native trees, predicting invasion risk is hard to do because those species may not have yet spread into all the habitats where they could get a foothold, like our area.
The ornamental plant trade and plants containing weed seed help non-natives get beyond dispersal barriers. Movement of plants around the globe by bird, wind, accident or sale is a constantly changing “evolutionary” process, and not necessarily a problematic condition. Climate change could alter more areas more rapidly by how the plants adapt. You can see this is a big problem keeping places free of non-native plants, and almost a fruitless and costly endeavor.
Native plants are more limited in their distributions compared to non-native plants, probably because they have a harder time dispersing into suitable climates without humans transporting them. Inability to disperse is likely keeping some native species from inhabiting a broader range. This includes migrating to far off places having similar soil conditions too. Climate change is believed to be less limiting.
Many scientists are saying that non-native plants will likely occupy more of their potential range over time. Native species occupy about 50 percent more of their potential range than non-native plants, but that could change. Now science is looking at the benefit of non-native plants more closely and whether wildlife will adapt. Why? Because they expect non-natives to become more pervasive.
It is like many things in life that have mixed blessings, when change happens adaptation becomes necessary. A tree with a nice shape, beautiful early spring flowers, roots that are deep, gorgeous fall color, feeds birds and insects when other plants are bare or not yet in bloom, mostly sterile, thornless, generally disease resistant, and is a small enough tree for many landscapes… yes all the good comes with a bit of bad – like most things in life.
But again, ask a bee.