Historically most of us cringe when a neighbor plants a flowering pear. I’m doing a favor for my neighbor and myself next year and top working a flowering pear for them. I know the seedlings are free rootstock but I don’t want callery rootstock that way because there is enough of it around already free for the digging. I turn around and purchase callery rootstocks frequently but I’d rather not have the seedling coming up everywhere. They are not currently an invasive plant in our state but they could become one if just allowed to breed in the wild. Wild plants can be incredibly vigorous because unlike the callery rootstocks I purchase only the strongest survive. Many of us use wild callery in spots where nothing else will survive as rootstocks. Every year I dig up as many wild pear rootstocks as I have time and energy to do. The good news is those people who are planting callery pears for their beauty are likely to find that in a few years they are planting triploids. See this original link about the new triploids Ashspublications.org and this link that elaborates slightly Triploid flowering pears reduce self-sowing | EurekAlert! Science News. The only downside is if you plan to use a flowering pear to pollinate your fruiting pear trees it won’t work or at least not very well. Triploids have three sets of chromosomes whereas diploids as the name implies have two. You will also hear terms like Haploid but that just means half of the chromosomes as diploids. If your looking for the more complicated answer on how diploids reproduce genetically unique trees see this link Meiosis - Wikipedia. The easy explanation is if a tree produces a lot of seeds such as is the case with todays flowering pears some of those seedlings develop immunity to fire blight and other diseases that kill their siblings. The surviving wild pears breed again, grow faster, breed again until you wind up with super flowering pears which is what you have in many open fields now in certain locations. If you see flowering pears my advice is graft them over as quick as you can. The original trees were said to have a lifespan of 20 years but I know of wild callery in this area that are said to be older than me without a spot of fire blight ever observed on them. Imagine if people keep planting diploids what the wild callery will be like in 50 years! We need only use Asian carp as an example of how a diploid species can get out of control quickly http://plants.ifas.ufl.edu/manage/control-methods/biological-control/chinese-grass-carp/. Imported species of carp, pears etc. have no natural enemies here.
If callery only last 20 years, does that mean that whatever you graft on them will also only be good for 20 years? No more pears for your heirs?
I think they can live longer than 20 yrs. On the way to work each morning, I passed by a column of Callery pears that at least 40 feet tall and I am guessing about 30 to 40 years of age.
Depends on the callery pear genetics but you can look at this link as an example of life span (15-25 yrs) http://www.clemson.edu/extension/hgic/plants/landscape/trees/hgic1006.html. As Tony mentioned flowering pears in this area have a tendency to live much longer than that. Tony is only a couple of hours away. I’m not sure why our pears have a tendency to live longer.
I’m pretty sure that 15-25 year ‘lifespan’ is referring to the fact that, due to horrible branching structure, most callery cultivar trees ‘self-destruct’ sometime… usually commencing not long after they hit 10 years, but sometimes later. Wind, snow load wreak havoc… and homeowners remove them. But, if they just cut 'em down, the seedling callery understock resprouts, and you end up with a thorny, seedling callery.
I’d hazard a guess that callery understock underneath a fruiting pear variety will outlive the average person.
We had two decent sized Callery pears in our yard when we moved in, maybe 10-15 feet tall. They had a few fireblight strikes on them, they were in bloom and stunk to high heaven, and then produced those tiny, awful little pears. I had no idea why anyone would plant them as there are numerous flowering trees that look nicer and don’t stink, and numerous ornamental fruit trees that actually produce usable fruit. I chopped the things down as soon as I could, and then when they constantly tried to resprout, I dug up the stumps and roots (a half-day’s solid work.)
I only wish I hadn’t been so hasty and knew then what I knew now. Undoubtedly they would have made great rootstock.
They have poor branch structure as well and maybe that’s what the experts mean though with many of the tame trees it’s disease they die from. Some varieties get more diseases than others though Bradford is actually very resistant to diseases in most cases. The aristocrat flowering pear does not have weak branches but is susceptible to fb http://edis.ifas.ufl.edu/st536. This is a good article to read as an example http://www.purdue.edu/newsroom/releases/2014/Q2/deadly-fire-blight-in-flowering-pear-trees-still-a-problem.html. If a neighborhood plants 100 of the same tree as contractors frequently do you can imagine if a strain of fire blight finds them what it will do to a susceptible strain of callery. Once the trees are top worked to resistant pear like kieffer, orient, or pineapple no problem because the disease never gets to the main trunk.
Right, Clark - that’s what I was alluding to - but didn’t verbalize it well enough.
The callery root system underneath a good fruiting variety should be, I would suspect, as long-lived as P.communis… no reason to think that fruiting pear on callery rootstock shouldn’t theoretically live 50-100 years or more.
For what it’s worth i have callery that has been alive under a pear for over 27 years. The tree looks like it is just warming up for how long it plans to live. There is some satisfaction in knowing though i might not live forever much of the things i did will make a difference far longer than anyone remembers my name or my story. Pears can feed many people and can be commercially raised in Kansas or most other places now.
Callery pears were widely planted in San Diego county in the 1970’s in municipal and residential settings. Most of them are in good health. All of them exhibit signs of fireblight in the Fall.
Recall you saying that they seem like a nuisance there since they carry fireblight.