Panicle hydrangeas can be cut back to just a few main branches in the spring and then still bloom in the fall. Something between pollarding and coppicing. My understanding is Little Lamb has small flowers, but is not really a dwarf shrub. Also look at Dharuma. It has a nice small stature. Ted

It is do-able. If you cut them down to the ground in the Fall (some people prefer not to see the sticks all winter long) or Spring, this will keep them slightly on the smaller side. If you find they are still reaching over the 6 ft. mark (wouldn't be for years and years though) you could always prune a foot off in the Summer. You'd be sacrificing blooms of course, but only from the very top--not that big of a deal really. So, is it ideal? Not ideal, but if you're willing to put in a bit more time to trim them up there's no reason why you couldn't shorten them up. Having the room for them width wise (which you have) is more important IMO because Summer pruning to control size would mean losing lots of those beautiful blooms.

Limelights are notorious for showing their feet as the growing season progresses but it is a little rare for two to leaf out a whole month apart when so close to each other. Mind you, I am not saying it could not happen, only that it would be odd. Also, I would never expect two originally potted (by the plant wholesaler) hydrangeas to grow at the exact same rate since one's root system may have been cut shorter than the other's root system, for example. So, I think we need more information. Let me ask you a bunch of questions to rule out other stuff... Does the one on the right -which is closer to the hose- get more water than the one on the left? Hoses sometimes leak water where they connect to the spigot and I am wondering if the area by the right Limelight then gets all this extra "leaking water". I am also noticing that the annuals in the extreme left appear to be slightly smaller than the annuals in the middle. It may be normal but I was wondering if the annuals were originally of the same size and were they planted there at the same time? So, exactly how much water does the one of the left get and how often do you water? Do you water both of them the same amount with a sprinkler or do you water manually? Have you ever had similar issues with other plants in that spot suggesting soil or watering problems? Is your soil hard clay that may sometimes be difficult for the roots to penetrate? Do they receive the same amount of sun (include indirect scenarios such as when the sun is reflected from the large windows towards the plants)? Is it somehow warmer or more windy closer to the step up? Does the general area in which they are planted suffer from underground pests that may disturb or damage the roots (think voles, etc)? Could the one the left be suffering from circling roots because it was pot bound for too long? Do you remember cutting off the roots that may have been growing on the sides of the pots? Where are you? Do you live where nematodes are present? Approximately when do they leaf out for you? Is your soil acidic or alkaline? Have you tested soil pH in that bed? Do you know if your soil has any type of mineral deficiencies? Do you fertilize these eventually large shrubs? When? How much? Does one shrub get more fertilizer than the other one? Any stories that you remember when you planted them? For example, did you notice when planting that the area near the left shrub was more rocky? Sorry for sooo many questions. I am hoping one might trigger an 'aha' moment though. I wish we could just "ask the plants"! ;o)

@kitasei2 Sorry for the late reply. I only get on this site to look at plants my wife has asked about planting. I used fishing wire the first two years to get the plants to mature. Looked very hillbillyish. Pretty sure my neighbor made fun of me about it during that time. Oddly he now copies much of what I do outside. The deer still munch on them but this is 60ft of hedge and at this point cannot be stopped by the 10 or so deer that come through.