Good grief! Wotta leaf!

Giganto-leaf

"Normal" leaf

We bought a bunch of citrus trees a few months ago and put them in plant containers on our south-facing deck. They are doing well and will probably have to be planted in the ground before too long. One of them, the Star Ruby Grapefruit, is behaving oddly. Its latest burst of growth has produced some leaves that we would expect to find in a tropical jungle, not the hot dry Central Valley of California. Some of the new leaves are at least five times larger than the plant’s original leaves, so I was pondering the possible cause.  Could it be—

• Higher elevation—we’re about 1,000 feet (300 m) higher than Fresno where we bought the tree
• Higher latitude—we’re at a position that’s directly east of San Jose where growth is rampant
• Gentle loving care—not some slave’s dull boring job
• Deep-well water—pumped by nice clean solar power, too
• Alien super-growth vitamins shot from a passing saucer craft on a moonless night

I like the last one. Besides, it sounds more plausible than any of the rest.