MARYSVILLE — Steve Smith believes the garden can be a lesson about life.

Variety is good. Living things thrive when they are together. Every plant, like every person, is different. Some are easy to work with, some difficult. There are those who keep mostly to themselves, while others spread out.

Smith finds joy in gardens that make heads turn.

“It’s always fun to create surprises,” he said.

For nearly 30 years, he has owned Sunnyside Nursery at 3915 Sunnyside Blvd. He and his wife of 21 years, Pauline Smith, live in a house on the property. Just beyond their back yard are greenhouses and outdoor displays, where customers wander among the fragrant, colorful scenery.

The Smiths are the third family to own Sunnyside. The Holtum and Peary families owned it before them.

For 70 years, Sunnyside has been a source of plants, gardening supplies and expertise.

To mark seven decades, customers are invited to a celebration from 10 a.m. to 4 p.m. Saturday. The event includes lunch, prizes, pumpkin painting, scavenger hunts, planting and discounts.

It’s a way to say, “Thank you,” Steve Smith said. “We couldn’t have done it without you.”

Like the nursery, he is turning 70 this year.

Steve Smith moved to Washington from California in 1989 with his first wife and four children. The priority wasn’t buying a business; it was finding a house that would fit the family.

“Really, we bought a house and they threw in a nursery,” Steve Smith said. “It was a seasonal ma and pa nursery at the time. I just sort of kept investing and expanding.”

It’s a 2-acre property. Half was horse pasture when he bought it — and has since been taken over by the nursery.

He started with one employee and now has 25.

The business is open year-round, but does half of its annual sales in about three months, from mid-March to mid-June. May is busiest.

“A lot of garden centers have closed in our 30 years here,” Steve Smith said. “It’s a tough way to make a living. You have to have a passion for it.”

Like other agricultural businesses, Sunnyside depends on the weather. One year, it rained nearly the entire month of May. Another year, a greenhouse collapsed under snow. Then there was the winter when a natural gas line that powered the heat in a greenhouse lost pressure. All but one variety of geranium died in the cold, and the one never bloomed — and never sold.

The nursery did OK during the recession. Though sales of shrubs and trees dropped, flowers were in demand. People stayed home instead of traveling. They wanted color in their lives.

Gardening is healthy for the body and soul, Pauline Smith said. Flowers are needed most during hard times.

Though the largest department in dollars is trees and shrubs, it’s the flowers that bring visitors. Hanging baskets, houseplants and potted plants are selling as people who live in apartments look to garden inside or on a patio.

“Most of our employees are crazy about plants,” said Pauline Smith, 72, who grew up in Seattle and has worked for years in horticulture.

Knowledgeable staff is one reason Carla Clemetson said she visits the nursery. She lives nearby.

“They have a really good reputation for healthy plants,” she said.

Clemetson has taken classes at Sunnyside. She put in a new yard last year and is slowly filling it with greenery. She came to browse Tuesday, and said she’ll return for the Saturday sales.

Megan Pulkkinen, of Poulsbo, is a landscape designer. She stops by Sunnyside whenever she’s in the area.

“There’s a lot of sameness out there,” she said. “It’s nice to come to a place with so much variety.”

On Tuesday, autumn sunshine fell on clusters of white snowberries, the royal purple blooms of a Veronica plant, and Black-eyed Susans that seemed to reach toward the light. Pink flowers that appeared soft to the touch attracted dozens of bees.

Signs pointed toward sections for seasonal plants, trees, perennials, vegetables and herbs, shade plants, roses, shrubs, and the classroom. Upcoming topics include bulbs, houseplants and conifers.

Steve Smith encourages aspiring gardeners to be adventurous.

“We live in a horticultural paradise,” he said. “It’s a great place to grow stuff. I hate to see boring yards.”

Steve Smith writes a weekly gardening column for the newspaper.

Kari Bray: 425-339-3439; kbray@heraldnet.com.