How odd. Can you post pictures? No, I have not noticed this but will look around other ES's in the area. I wonder if that is trying to imply that there is a problem with crown???

To produce (or try to produce) more shoots at the crown, I guess I would experiment with increasing the soil levels of nitrogen above the amount that the fertilizer calls for in order to induce new growth but stop fertilizing sometime this month (June) so the plant is not damaged by early frosts. So if the fertilizer says to apply 1/2 cup then I would add 3/4 cup and so forth. Increase it further as needed. Try using Blood Meal as it is mostly nitrogen, organic and slow-release. I would also purchase one of those soil kits that lets you analyze nitrogen levels. Save notes with the kit's nitrogen readings.

Trunks at base of plant (there are 2 here):

Overall size of plant (doesn't get much larger than 2' tall each year):

I was doing some research on propagation and had another idea. Maybe this other suggestion can help you. The only problem is that I have usually seen it used in earlier in the year, not in "almost" Summer. It is called mound layering, stool layering or just plain stooling. It is like a more "enhanced" version of ground layering. You prune the existing stems down to 1-2" in winter (or in the Fall since your winters are colder than mine), build a mound with soil and top it with mulch. This encourages basal breaks that may produce roots and hopefully make the crown get bigger in time. Not an overnight process; may take several years.

Here is a link that might be useful: Stooling

Yeah, that's the kind of thing I was afraid of. For that amount of work, I can pickup some clearance 3-gals of ES with properly structured crowns and just dig up the two problem children and keep them in pots.

Be advised, ES fans! This information could save you a lot of headaches!

Thanks Luis!