Napa Valley, one of the world's premier wine growing regions, has an uncommon problem these days: not enough new grapevine root stock is available to supply the massive replanting that's under way there.

A trifecta of developments has created the critical shortage:

Aging cabernet vines planted after a deadly phylloxera outbreak in the 1980s are due for replacement that was deferred for years as sales of premium wines slumped in the recession.

With demand again strong, growers are taking the opportunity to replace old vines with varieties and clones better suited for their microclimates. Others are reconfiguring rows to prevent erosion into sensitive streams, or to allow mechanical harvesting machinery to access vines.

All of this activity caught commercial nurseries across California short of supply. Some are sold out for 2013 and are taking orders for 2014 and beyond.

For more, see: Massive Napa do-over prompts grape plant shortage