Stan Labik's greenhouse is filled with amazing flowers -- from an unlikely source.

"A lot of people think cacti are ugly, but you can tell by a lot of the flowers. The flowers are really nice," he says.

In fact, they are stunning. Luminescent red and yellow blooms perch upon gray-green globes guarded by sharp spines. Clusters of yellow flowers act as a foil for a cloud-like blanket of pure white needles.

Standing in Mr. Labik's greenhouse in Harmony, Beaver County, it's easy to see the irony of fragile, beautiful flowers growing on harsh, leathery skins. He has more than 100 types and many of his favorites come from exotic locations like South Africa and Madagascar. Most bloom in early spring, starting in April, and some bloom again. He propagates them by taking cuttings and rooting them. He's tried growing them from seed, but he says that takes forever.

Growing cacti is not for the impatient. Mr. Labik, 62, works in his greenhouse nearly every day. The retired postal worker says it keeps him busy. During a recent visit, he was weeding methodically around the thorns with stainless-steel tweezers. Despite his care, he can't avoid all of the needles.

"Every day, I'm usually pulling spines out of my fingers. Some of them you can't even find until later on," he says laughing.

One day, while working in his first greenhouse, he lost his balance.

"I went to catch myself and I got stuck with a spine about 3 inches long. They do hurt," he says, stating the obvious.

Mr. Labik's hobby began as child, when he would watch his mother growing plants in the house. In the summer, she brought them outside.

"I started taking care of them because she was ignoring them, then I started on cactus and I got carried away."

That's an understatement. Close inspection shows a wide variety of sizes, shapes, textures and colors.

"I just like the way they grow. There are so many different types. It's amazing."

Mr. Labik got burned out and gave up on the hobby in the 1990s, donating almost all of his plants to Phipps Conservatory and Botanical Gardens. His greenhouse at the time was much bigger and he was overwhelmed. It was either let the plants die or give them to Phipps. He only kept a few, but he soon longed for more.

"I missed them," he says, adding that he found out later how valuable some of his gifts were. "I wish I knew that back then."

He keeps his cacti in the greenhouse year-round. They grow in Sunshine Potting Mix, an unlikely material for a cactus, but Mr. Labik swears by it. He says the mix holds water well but dries out quickly, just what these plants need. For years, he mulched the top layer of the potted plants with stone, but has since discontinued that practice.

"They are easy to grow, but you have to watch so you don't overwater. It's better not to water than overwater."

He waters once a week and fertilizes with Miracle-Gro. In the winter, he lets the plants go dormant, giving them no water at all until spring. A heater maintains their preferred hot, dry climate when it's cold outside. Mr. Labik lost a few cacti last winter when the power went out for a couple of days.

His collection continues to expand, even though greenhouse room is limited. Asked when he'll stop acquiring cacti, he responds with a laugh:

"Not till I drop dead. Then I don't know what's going to happen to them."