My garden surprised me over the weekend.

I was watering the pots on my deck, when I noticed something new -- a spiny arm jutting from a squat potted cactus, with what looked like a flower bud at the tip.

Sure enough, the next morning brought a rare treat -- a huge beautiful white bloom.

I've had a few cacti over the years, but never before gotten one to flower, so this was a delightful surprise. The cactus is one of several in a bowl-shaped planter that I gave to my mom a few Mother's Days ago. It spent summers on Mom's deck, and winters inside near a window. Nothing ever bloomed.

I inherited the cactus bowl last fall after Mom downsized to a condo. The cacti were not happy in my bedroom, where they spent the winter. They were shriveled and sad when I moved the bowl outside around Memorial Day. But they've thrived over the last few weeks on my sunny deck.

The sudden appearance of the flower made me curious about cacti and their blooming habits, so I started Googling around, trying to figure out what I was doing right. It may have been just a question of timing. Some types of cacti take years to mature and produce blooms. Or maybe this cactus just likes the intense sun it's getting on my deck, which is west-facing, unlike my mother's, which faced the east.

The beautiful white bloom was extremely fleeting. By Sunday afternoon, it had already begun to close. By this morning, it was gone, and its spiny stem was limp and drooping.

But it whetted my interest in trying more cacti varieties. There's a great cactus resource for Minnesota gardeners at www.cactiguide.com/, a website created by Long Prairie cactus lover Daiv Freeman. I visited Freeman a few years back at his home and Sauk Centre greenhouse and wrote about his lifelong fascination with cacti. Here's a link http://www.startribune.com/growing-cacti-is-a-prickly-passion/120232224/

Any other Minnesota gardeners out there who are growing cacti? And what have you learned about getting them to flower?