I just checked my Vanilla Strawberry--no yellow leaves at all.

On most plants, yellow leaves can mean too much or too little water. My understanding is that hydrangea like extra water, so I'm guessing that maybe your VS is not getting watered enough, especially if it is in full sun nearly all day like mine is.

Mine gets fairly frequent watering since I have a number of roses planted near it and VS gets the overflow of water from roses--which like lots of water in hot weather also.

Kate

Might be too much water combined with enough shade for thr plant to no longer require interior leaves. I just transplanted one and have needed to water it to reestablish. It has since had a few leaves do this. Not a major issue.

If too little water the exterior leaves will droop. Since yours look ridge, perhaps too much water but also they just tend to shed some inner leaves. I get that all the time to a very slight degree on all H. paniculata cultivars.

If this is newly planted (this season.... and I am willing to bet it is), then this is "normal" ..... It has nothing to do with watering.....
As soon as the flowers start blooming on "newly planted" paniculatas, the roots of these plants can not support the added task of supplying water to the flowers, so they drop some of their leaves.....
I have worked at a nursery for 10+ years and this is a common thing that happens.....Your hydrangea will not do this next year. after it becomes established.....

This post was edited by ians_gardener on Sat, Jul 12, 14 at 7:14

Thanks everyone for the advice. This is the 2nd year for the Vanilla Strawberry - it did the same thing last year. My Little Limes, 3rd year for them, also get the yellow interior leaves. They all get full day sun, and I just let Mother Nature water them, so could be, I'm not watering enough. Seems like the Little Lime would be established by now, & I've read they are drought resistant. It does make me wonder if this yellowing of leaves may be "normal" for the paniculatas.