Leaf in photos appears relatively glabrous to me, indicating M. alba. In my experience M. rubra is noticeably "scabrous" (rough) on the upper surface.

M. rubra = "leaf blades adaxially with short, stiff, appressed hairs providing a scabrous texture, abaxially sparsely to densely pubescent across the surface"

Here's a photo I took of M. rubra leaves (from TN):

In your (arbordave) picture leaf venation looks noticeably different from that of M. alba also.

Leafs on what I got are very scabrous, very rough, cannot be compared to Morus Alba weeping which I have. Picture doesn't show that. Also, someone mentioned that on my picture buds are indeed close to red colour - main feature of M. Rubra are red buds. Probably hybrid, but very close to Rubra.

Agree that it could be a hybrid. This publication says "Hybridization with white mulberry has been reported extensively in Ontario, where red mulberry occurs along a portion of the northern range edge, and according to Ambrose (1999) most Ontario sites for red mulberry co-occur with white mulberry. Genetic studies conducted by Burgess et al. (2005) confirmed a relatively high degree of hybridization, with the hybrids expressing a dominance of white mulberry markers in their genome and thus the potential (owing to introgression, or repeated backcrossing) for the genetic dilution of red mulberry."

In addition the 'Illinois Ever-bearing' hybrid horticultural selection has been grown and sold for years.

Crossing the White and Red species results in a tree with the most desirable attributes of both

http://arthurleej.com/a-mulberry.html

The typical Morus rubra leaf shape is a large oval with a long, pointy tail. And they are also leathery in texture (as opposed to glossy smooth for alba).

+blakrab NoTex

- thank you for the picture; yes I got cuttings of exactly such looking tree - it was in flooded site, government tried to clean site and tried to cut (badly) tree. It had exactly same looking leaves, big, rounded, rough, very leathery. And it was growing almost in a water. Very young mature tree, maybe 8-10 y.o.

I also have Illinois Everbearing and leaves are almost the same (this is very young tree, under full sun), except that glossy:

What I noticed from past experience, seedlings of different species may look the same until mature age; seedlings of Morus Rubra may look the same as seedlings of Morus Alba first few years. For example, I have 1 year old seedlings of Morus Alba which look the same as my Morus Nigra: rough not-lobed leaves. But under sun in backyard it started mature, stared becoming shiny.

All mature fruiting wild mulberries in my area (I have about 15 at golf-club border, and about 3 in small park) have very regular and very shiny leaves, absolutely sure: M. Alba, super easily propagated by birds, all my neighbourhood has it as weeds inside hedges etc. But seedlings of Morus ALba, or for example new branches after heavy cut, have very lobed and much bigger leaves.

Pictures of my 14 y.o. heavy-pruned Weeping Morus Alba Tatarica, leaves and buds, it looks the same as what I found in a park, except that size of leaves 10"-12" and small sharp teeth on leaves margin on a variety I found vs. big rounded teeth on margin on Tatarica and size is twice smaller:

Logically thinking: I found 3-4 years old seedling with 11" huge leaves in a full shade, sharp small teeth on leave border, etc.; I suspected it to be Morus Rubra. But: if it is seedling then we have mature tree around? No we don't, what I've seen (mature, fruiting) all have regular small shiny leaves.

SO it is just nice specimen, 10-th generation+ hybrid, maybe some influence from M. Rubra: shade tolerant, flood tolerant, huge leaves.

Government listed 300 M. Rubra in Ontario, and published map of distribution. I am wondering what happened? did we have 30,000 rubras last century? And M. Alba is "invasive" - how can M. Alba kill M. Rubra?

M rubra often hybridizes w/M alba. Yours might be an example.

In so many places I've read that Alba has smaller leaves (few inches); and Rubra has huge leaves (over 10 inches). Also, I've read that Alba's "teeth" on the leave margin is not as sharp as Rubra. And that Rubra is shade tolerant, can survive in a flooded area, and so on. I found few mulberries as per description, in different places, around creeks in Toronto, yes seeds could swim from very far places.

Yes, of course we need DNA analysis :) which may say that grand-pa of this mulberry was from Canada, and grandma from USA :)

Fuad, here's a pic of what I was pretty sure was a F1 (first generation) hybrid because there was a true red mulberry close by & also white mulberries. Leaves were somewhat fuzzy, leathery and tops rough like red mulberry, but not as much. Obviously they are very large:

beng12 exactly, I've seen this kind, few; in super shaded watery area; perhaps hybrid, but very close to Rubra descriptions.

BTW leaves on my "Montreal Mulberry" (and I suspect it is Illinois Everbearing) look very similar:

It's said a real problem is red mulberry getting "hybridized out" by the far more common & invasive white mulberry. IOW, the pure red mulberries are disappearing...

Here are some of my mulberries, including Montreal Mulberry (Illinois Everbearing? or Shangri La? grafted; it is Morus Rubra & Alba hybrid; it has super nice weeping habit), Morus Macroura (Pakistan or Himalayan, 4" long fruits), and Black Beauty (I believe it is Morus Nigra)