How to cultivate cultivars

Nancy Buley is Director of Communications for J. Frank Schmidt & Son Co., wholesale tree growers of Boring, Oregon. During her Cultivate education session, Cultivating Cultivars: Urban Tree Cultivar Development, she explains the lengthy process of tree cultivar development.

A formula for tree cultivar development is time + skill + patience = trees. It takes a lot of all three elements to produce quality trees, especially time.

“To grow tree trees it requires a great deal of optimism and faith in the future,” Buley says. “We're looking at crops that are five to seven years out, and the crystal ball isn't as clear as people might think. There's a lot of guesswork, and it’s a really challenging business.”

Field/Liner Production Timeline

Growing trees is a team effort, and trees go through many phases on their journey to the landscapes. The propagation process usually runs for five to seven years. Then the trees are sold as bare root or in small containers to a grower. The entire production timeline ranges from six to 17 years or more.

• Years 1-3: Planning, seed, cuttings, grafting, tissue culture
• Years 2-3: Transplant seedling to field, bud scion wood to rootstock
• Years 3-7: Grow and train grafted transplant

“Propagators plus growers plus time, and you’ll have landscape-ready trees,” Buley says. “We're always looking five to seven years in the future, and one of the challenges is sourcing seed and cutting materials and grafting materials. That takes a lot of planning to match up the number of buds you need for the number of seedlings you've grown, and just getting all that ready so you can start pepping the fields and estimating labor.”

J. Frank Schmidt & Son Co. propagate from seed and cuttings, and they contract with several micro-propagation nurseries. The cuttings root quickly in the humidified area in their hoophouses. The cuttings will be in the hoophouses for a season. Then they’ll be dug and transplanted in raised beds for another year. Then they go into the field, and a season later they’re one-year trees.

“So that one-year tree is actually a three-year-old tree,” Buley says.

Next, they stem the trees and bring up one bud. Then every week stakes are put down to make sure the trees are nice and straight. The trees will be pruned, graded and off to the customers.

New cultivar development

“If you think tree production takes a long time, new cultivar development takes generations – a minimum from 15 years to 50 years or more,” Buley says.

J. Frank Schmidt & Son Co.’s new tree development goals are: the tree has to be better than what’s already in the marketplace. It has to have unique traits that no other tree in that species has, whether it’s foliage, flower forms, resistance and more recently, adaptability to climate.

“We’ve been looking at this warming climate and testing for and selecting for adaptability, for resilient to drought and heat in urban settings because our wheelhouse is urban trees,” Buley says. “We’re wanting trees that are adaptable to urban settings.”

Buley explains whether specifically crossed or open pollinated, a typical selection might look like this:

• Year 1: 5,000 seedlings
• Years 2-3: Keep 500
• Years 4-5: Keep 50 -100
• Year 5: 10-15 receive a code number
• Year 6: Begin growing trials with trees that have received a code number
• Years 10-15: Consider introduction of 1 tree (maybe) from the 10 to 15 that received code numbers

Advantages of cultivars for landscape trees: predictable, superior performance in landscape settings, vigor, diversity in species and improved pest and disease resistance.

“In landscape settings, you really need to know what the tree is going to look like,” Buley says. “As opposed to whether it might be wide or narrow. Landscape designers really want to know what that project is going to look like and how those trees are going to fit, so it assures their design integrity.”

Key takeaways for new cultivar development:

• Not just new, better
• Unique traits
• Resilient in urban environments
• Natural disease & pest resistance
• Easy care & well behaved
• Can it be grown profitably?