I’m not really sure what the cause is, but of my 2 CJ plants (which are a couple years older), just one sends up suckers and it is usually just one from the same place each year, although this year there are a few right near the base. I’m leaving the close suckers as backups since I had one CJ unexpectedly die, but it might have been from wet feet. The CJs are in a slightly mounded row beside my driveway, but it is only slightly elevated.
My Juliets on the other hand are suckering machines. They are planted in different areas. One in a mounded area at the end of my raspberry row and one on a slight incline about 12 feet away. The one on the incline does sucker toward the lower side, so maybe that is related to the roots being closer to the surface… although some of the suckers have come up in a raised bed about 8 feet away.
I wonder if planting in mounds would help creating suckers or not, since it probably gets the roots closer to the surface as they grow beyond the raised area?
The only other thing I can think of as a trigger, unless Juliet is just that much more likely to sucker than CJ, is that the areas where my Juliets are have more varied plantings and the soil types would change as the different plants were put in with slightly different soil preparations and amendments. Maybe as the roots hit a different (richer and looser) type of soil near another planting it triggers them to sucker. They are either suckering at the area that would be just beyond where I dug their hole and roots hit the packed native clay soil, or near other plants where they go from the clay back into soil that has been loosened and some manure or other amendments added.
