if lifespan/productive years is a vital aspect in one’s consideration, bradfords may not be topnotch, considering that some pears are the longest-lived among common pomes.
bradfords start declining at age 20…maybe other callery cultivars live longer
https://guilford.ces.ncsu.edu/2013/10/bradford-pear-a-mixed-blessing-in-the-landscape/
Eboone,
Yes a new pollinator is it exactly and likely aristocrat. Bradford had a problem with weak branches so sometimes storm damage would occur. Bradford was sterile so it was harmless. Many new varities such as aristocrat were developed to prevent branch breakage during storms. Sometimes Asian pears top would die due to fireblight etc. Leaving bet rootstock to grow in its place it was grafted to. In light of those changes a one in a million chance seed would be fertile and grow from some variation of those conditions. The result was a new variety 100% fertile and 70% of the seed is viable and a hybrid stronger than ever. Trees revert back a generation or two and with callery that is a wild thorny tree that’s very resilient. As those small fruits are eaten by birds the seeds are spread fertilized by bird poop. As with anything in nature the variety gets stronger by natural selection. They are resistant to fireblight and other diseases, rodents, bugs, and deer.
First Asian pears I planted were on Harbin rootstock.
I’m not in a particularly cold zone, so I’ve never sought out ussuriensis, and have just used whatever I had available - mostly volunteer seedling callery, with or without the OHxF 513 interstem.
Come to think of it. I grafted 20th century to my dads Bardford Pear last year and they grew well. Even though they were grafted low on the canopy and I did not top work the tree. They received very little sun. More of an experiment than anything else.
jujube,
The seedling callery i use as rootstock here are going on over 25 years now and highly vigorous. Your right though to mention this because you never know what your going to get. I’m not sure we will know it all in a lifetime. Scientist are well aware of many other influences the rootstocks have not just in size of fruit but mineral value http://www.sciencedirect.com/science/article/pii/0304423884900438. Things like lifespan, fruit size , quality, production etc are not well understood by those of us who grow fruit. I suspect what we know only scratches the surface.
first things first-- hope i didn’t sound like a naysayer when i posted it and apologize if it came off as that
and most definitely, am glad yours are are still vigorous! Maybe your callery is not a bradford and possibly a longer-lived cultivar. Or may in fact be a bradford and it just so happened that your locale is more conducive to longevity.
the link i posted was published by N. Carolina State U - and even if you are in N. Carolina, it is still a sizeable state where regional differences are to be expected. And that includes differences in the expertise in cultivating one’s trees. Some links even say bradfords may start declining at age 15, so evidently yours are very happy with the care they have been getting.
jujubemulberry ,
I think that’s a very good point you brought up and I’m glad you did. Your right that a true Bradford pear are very short lived. No one really knows how long callery rootstock like my oldest will live. These are some of the cultivated variants of callery listed below. Bradford typically are lost to storms but not all of the other ornamental pears have that flaw. The wild callery are durable and I actually have friends with some on their property that are very old. A nearby town a tree stands that a friend dug seedlings from 30 years ago and the tree is still there. What is it? I don’t know for sure but I suspect its a hybrid. The urbanforestnursery made these observations about callery varieties they posted to their website
" 'Aristocrat’ A wider form tree with branches at right angles to the central leader. The distinct characteristics of the leaf are its wavy edges. Fall color is not as reliable as others, but if you have the crown space, the Aristocrat is a fine selection. Older trees are reported to reach 40’ high by 25’ wide.
‘Autumn Blaze’ This tree is not recommended unless the site is very protected from wind. Although the form is round and the color is better than most of the pears, the limbs are incredibly brittle. Even if you get trees to the site undamaged during handling and shipping, winds will tear the tree apart for many years. From my experience, this one should be listed along with the original Bradford Pear.
Cleveland Select Flowering Pear’Chanticleer’ (same as ‘Select’, ‘Cleveland Select’, and ‘Stone Hill’). The most popular, as well it should be, with its upright pyramidal growth, relatively good branch structure, and consistent qualities listed above. This cultivar was reported to reach 35’ high by 16’ wide after 15 years.
‘Cambridge’ Appears to have cleaner, more regular ascending limbs, smooth bark, with orange fall color. It is narrow like "Chanticleer’.
‘Capital’ Even narrower than the ‘Chanticleer’, so for a narrow space, this is the better choice. I have found the branch structure not to be as consistent or attractive in its winter show. The tree is said to grow to 32’ high by 8’ wide in 15 years.
‘Jack’ This tree is the smallest pear cultivar I have seen, growing to no more than 15’ tall by 10’ wide. This tree has a dense branch structure and very slow growth. Call for it more as spaces for trees get shorter and tighter. Check out the Jack Pear tree profile here.
‘Redspire’ This tree has a moderately pyramidal form, less than Chanticleer. I have found it to have some brittleness, thus somewhat susceptible to wind breakage.
'Bradfords’ are known for their extremely tight crotches and severe splitting apart as they mature. This cultivar was the first selection of Pyrus calleryana. Most of the older Bradfords have literally split apart. Avoid this one along with the ‘Autumn Blaze’ " as found here Tree Profile for the Flowering Pear - Urban Forest Nursery, Inc.
In Kansas I frequently go observe wild callery and other types of pears. A friend mentioned a location with wild pears on his property and asked me to hike out there and determine what they were. The pears were as expected callery pears but that was when the surprises started. Typically the species has pea sized fruit. These trees for the most part were typical callery pears except for one tree which is shown in this photo. 
As mentioned the above tree is no Bradford nor is it short lived. It’s been there around 25 years they knew of. They bought the property then to deer hunt and the deer eat this fruit. Here is another wild pear with more typical fruit as a comparison below.
Oddly I found non producing and producing pears in this area well over 100 years old.
the pics show stark differences, no doubt.
and most certainly, there will also be differences in hybrid vigor and lifespans, since cross-breeding between cultivars occur quite readily. Also intriguing that callery pears seem to have more viable seeds when hybridized.
That larger pear is exactly what I have growing wild . Very astringent . Lots of pucker when tasted .
Jerry,
Do you have any pictures of yours? They could be getting DNA from asian pears as well which are Pyrus pyrifolia - Wikipedia. They look a lot like them. The future of rootstocks will be interesting because there are a lot of pears to chose from for breeding Pear - Wikipedia. Callery are adapting before our eyes. Eventually they will be living hundreds of years with larger fruit to attract more things to spread their seeds. They have already naturalized to many states and i’m confident they will naturalize here as well. In time the diseases such as fire blight etc. will have no effect whatsoever on them. The thing about nature is it either a tree adapts or dies and the thing that competes the best for resources will win.
Not sure if I can find pictures . I doubt Asian pear as I think none were growing in the area that far back . I have grafted the larger trees . They are very thorny when small . I bought the acerage in 1981 . There were mature wild pear trees here then . They were very tall due to reaching for sun in the woods . About 8 inches in diameter . They died eventually . The leaves look like pear .
Jerry,
An old callery pear could possibly be part Asian pear because kieffer is a cross of Pyrus communis (Bartlett) x P. pyrifolia (Asian sand pear ) and that’s where I believe some of those got their pollen. Peter Kieffer started selling kieffer pears in 1863. He said originally the sand pear cross called kieffer was an accident. There is no perfect rootstock but I read up on them and stay as current as possible. This is a good article about pear rootstocks http://whatcom.wsu.edu/ag/documents/treefruit/pnw341e.pdf. The article from wsu.edu suggested that some callery are vigorous enough to use for Asian pear rootstocks. There is such a wide variability of callery. They mention they are not cold hardy but the wild type is very hardy here.
How did your ayers graft turn out this year?
I will have to take a new picture . I have not looked at it in over a month .
Got new pictures .
Up to 6 feet of new growth . I have one on callery in the garden that put up 7 feet .
my asian pears are extremely dwarfed on pyrus calleryana ( and thanks to this thread now I know why) but they bear very early. The only two that have grow to any size are chorjo and megestu. The rest are basically sticks growing out the ground that just leaf out every year, with the exception of shinko that is more a bush form. . My yakmo on calleryana that is just a ft tall stick with one branch has done nothing but leaf out for 6 years and counting, except the third year where it bloomed and made 20 asian pears the size of marbles. My euros on the other hand grow like weeds on calleryana my meadows, santa maria, orcas, and seckel are 6 years old over 20 ft tall and over 10 ft wide , all of my other euros are this are doing excellently. So, Pyrus calleryana good for euros bad for asians!!
This political advertisement was paid for by pyrus calleryana tree for president 2016!!
I had the same experience this year after grafting 3 euro types and 3 asian type pears to a callery. All the euro types took and grew 5+ feet while all the asian types failed.
Does anyone know a good interstem for getting asian pears to grow on a callery pear rootstock?
Use one of the three euro pears you grafted as an interstem.
