Welcome to Crablandia

Graphics from Adobe Stock

Take a short walk at the Secrest Arboretum in Wooster, Ohio, and you may set foot in Crablandia. The arboretum at the Ohio Agriculture Research Development Center is part of Ohio State University’s College of Food, Agriculture and Environmental Sciences, and it is home to America’s largest collection of crabapple trees. If you time your visit to late April-early May, you could see more than 300 crabapple trees in bloom.

The arboretum includes 84 different taxa of crabapples, replicated and randomized on a plot affectionately known as “Crablandia.” One taxa may do well in one area, but fail in another – even within the same acre of land. Overall, 311 trees are residents of Crablandia. The arboretum boasts 555 trees and 167 taxa and the entire Wooster campus claims 701 total trees. Crablandia is the keystone plot of the International Ornamental Crabapple Society, a group of like-minded #malusmaniacs and #crabaholics who study disease resistance and ornamental features of crabapple. It’s the product of nearly 40 years of work.

Flowering crabapple trees (Malus spp. and cultivars) are widely cultivated and planted for ornamental purposes in the northeastern and mid-western regions of the U.S. and in southern Canada. They are cherished by landscape architects and designers worldwide for their range of features. They vary in flower color, fruit color, leaf color, bloom time and tree shape, from weeping and spreading types to rounded and columnar forms. Nurseries and plant breeders have tapped into this diversity and have produced and named more than 700 cultivars.

With such wide range of diversity within the Malus genus, crabapples can fit into numerous landscape scenarios. Unfortunately, there are diseases such as apple scab (Venturia inaequalis), bacterial fire blight (Erwinia amylovora), and frogeye leaf spot (Botryosphaeria obtusa) that can and do cause damage to crabapples. Damage from these diseases can range from slight aesthetic injury to death of the tree. This, according to Jim Chatfield, a horticulture educator and professor emeritus at Ohio State University Extension, is why Crablandia was founded – to help determine which crabapples would pass muster, which could weather the conditions and show resistance to those diseases.

Founding Crablandia

The circumstances that led to the creation of Crablandia began when the International Ornamental Crabapple Society was founded in 1983.

Chatfield recalls Bob Lyons, founder of Sunleaf Nursery in Madison, Ohio, Les Nichols, a professor of plant pathology at Penn State University and Thomas Green at the Morton Arboretum in Illinois (the society’s first executive director) were key players.

“The idea ultimately was, we’ve got these problems with the apple scab,” Chatfield says. “It’s a disease that makes the plants look ugly. Not that apple scab was a devastating health problem, but it makes the crab look terrible. So wouldn’t it be nice if we had some data from around the country? Disease pressure is different in a region with cool, wet weather than in a hot, dry climate.”

So the members of the International Ornamental Crabapple Society set up plots around the country to test crabapples in different climates for disease susceptibility, with the goal of making for better planting and sales planning for nursery producers and a crop worth tens of millions of dollars annually.

Bailey Nurseries in Minnesota and J. Frank Schmidt & Co. in Oregon were both very involved in the early trials, Chatfield says. At its peak, there were 19 in different locations around the U.S., Chatfield says.

Some were set up in randomized, replicated blocks, like the Secrest site. Others were set in sweeping areas for landscape appeal. No trial sites were in the South, as crabapples don’t thrive there. The furthest attempt was in western North Carolina. Chatfield recalls visiting the Mountain Horticultural Research Station and seeing the crabapple plot.

“They tried,” Chatfield says, “But it was not only the disease pressure behind the not thriving — the Japanese beetles were just so bad.”

But overall, the plan worked. The trials provided nursery growers that are shipping to other states an understanding, with data, of how these trees will perform at their destination. For example, Chatfield could tell growers that ‘Hopa,’ a popular spreading habit crabapple in other regions, had a disease problem in Ohio.

“We called 'Hopa’ in our plot here ‘no Hopa’ because it would be horrendous,” Chatfield jokes.

Another crabapple that had heavy scab problems in the Secrest trial site was ‘Thundercloud,’ an compact upright with pink flowers and striking dark foliage. However, if you saw that tree at the University of Idaho’s trial site, ‘Thundercloud’ was fantastic. Low relative humidity and very little rain make for excellent conditions to avoid the diseases that typically plague Malus.

“There, you saw what the point of the tree was,” Chatfield says. “Here, the dark purple color of the leaves was muted by the fact that they looked horrendous. Dark, but covered in scab lesions.”

The researchers staffed at the plots worked together to collect data and publish results every few years, to keep a tally of which cultivars were handling the disease pressure well. A typical plant evaluation will entail rating all trees on the plot on a 0 to 5 scale with 0 = no scab observed; 1 = less than 5% of leaves affected and no aesthetic impact; 2 = 5 to 20% of leaves affected, with some yellowing but little or no defoliation, moderate aesthetic impact; 3 = 20 to 50% of leaves affected, significant defoliation and/or leaf yellowing, substantial aesthetic impact; 4 = 50 to 80% of leaves affected, severe foliar discoloration and defoliation, severe aesthetic impact; and 5 = 80 to 100% of foliage affected, with 90 to 100% defoliation.

In Chatfield’s latest published evaluation at Secrest, fourteen of the 80 crabapple taxa tested maintained superior scores (1 or less) through the entire growing season. These taxa included: 'Adirondack', 'Dolgo', 'Excalibur', 'Foxfire', 'Guinevere', 'Holiday Gold', 'Lollipop', 'Sargent', 'May's Delight', 'Prairie Maid', 'Strawberry Parfait', 'Tina', 'Camelot', and 'Red Jewel'.

In the early days of the International Ornamental Crabapple Society, there was a financial push to research crabapple, but that has waned.

Jason Veil, curator of Secret Arboretum, says crabapples aren’t as popular as they used to be. Part of that has to do with the climate in which they thrive shrinking.

“It really depends on where you are,” he says. “With climate change, you're seeing less and less. Like a lot of plants, you used to be able to use them in the Mid-Atlantic. Well, with our warmer days and higher humidity and higher precipitation, even crabs that were popular in New Jersey and Pennsylvania now are relegated to New England and the Upper Midwest.”

The society was moving along at a vigorous clip, but started to lose steam as interest in the tree dwindled. Crabapples were overproduced in the market, industry allies moved on to other jobs in other states or retired, and the association stagnated.

“I eventually became the president and it became a bit clear into the early 2000s that I might become president for life,” Chatfield says.

Chatfield and his cohort Erik Draper, OSU Geauga County Extension educator, had a three-year plan to visit all the trial sites. But the society just sat for 18 years, mostly dormant. Until Chatfield received a call from the other side of the world.

Strawberry Parfait crabapple / Jim Chatfield, OSU Extension

The China connection

In 2017, Chatfield was invited to speak at a crabapple symposium in China by Dr. Ling Guo of the Beijing Botanic Gardens. The two were colleagues from her time as an Ohio State University doctoral student. When Ling returned to China, Ken Cochran, previous curator at Secrest Arboretum sent cuttings with her. Ling rejuvenated the gardens with propagation material from the U.S.

Culturally and historically, the crabapple is very significant in China. Hai tang, as they call it, has been revered in China for 4,000 years. It adorns locations like the Great Wall of China, the Imperial estate and the Summer Palace outside Beijing, where in combination with peonies they symbolize honor, health and distinction. It’s been immortalized in works of art. Paintings and poetry have been devoted to the humble tree. It is ubiquitously planted in massive rows along public highways and it decorates the landscapes of private villas.

“It's similar, I think, to the cherry blossom in Japan,” Veil says.

In the U.S., selection often happens by chance. Like when nurseryman Bob Simpson of Simpson Nursery looks out in his Indiana field of Malus sargentii and notices one has pink pinwheel flowers. That was the origin of Malus sargentii ‘Candymint.’

Chatfield was stunned at the level of excitement and investment the Chinese have poured into his beloved crabapples.

“The Nanjing Forestry University has a crabapple institute, and in between faculty and post-docs, they have 43 people working on crabapples, and most of it breeding,” he says. “So they will bury us. I mean, it's not Khrushchev and the Soviet Union, but they're just putting money into it. I met a bunch of scientists, working on unbelievable stuff.”

In his time in China, Chatfield saw many amazing crabapples. But it also was a reminder that every plant must be in the right place to be successful. ‘Royalty,’ ‘Radiant’ and ‘Van Esseltine’ are beautiful crabapples that thrive at the Beijing Botanic Garden and in many locations in China. Chatfield says Ohioans cannot sustainably enjoy these because of their wetter springs, which lead to problems with apple scab and fireblight.

Chatfield says there is much collaboration between China and the U.S. to come. Many of the graduate students Chatfield met in China have since come to the U.S. to work at universities in horticulture programs.

Crabapple comeback?

After his China trip, Chatfield went to the University of Georgia to visit professor emeritus (and frequent Nursery Management contributor) Michael Dirr and Donglin Zhang, UGA professor of horticulture and another Malus appreciator. Zhang cajoled and coerced Chatfield and his compatriots to restart the International Ornamental Crabapple Society.

Chatfield has retired his president for life status, Donglin Zhang is the new president and Jason Veil is the executive director.

In Spring 2020, they were going to have a program in Beijing. It was, like many events, canceled to due to the COVID pandemic. In 2021, the society had a Zoom conference. In China, they had the in-person conference.

“It's not easy to resurrect a plant society,” Veil says.

And despite their popularity in the Far East, it’s been a while since crabapples were cool.

“In this country, a lot of it has to do with fashion,” he says. “Plants come in and out of fashion. When I think of crabapples, most people think of the 70s and 80s. That was the hey-day.”

But there is a market, a niche that the Malus genus fills. In the Midwest and the Northeast, there aren’t a lot of flowering trees. You’ve got the legion of Callery pears that have been causing trouble and deemed invasive in many states. But you don’t have crape myrtle, you don’t have hardy selections of redbuds and cherries.

A lot of the early, flamboyant flowering trees can’t handle the northern climates. So what needs to be done to change the hearts and minds of growers and consumers?

“There are plants that are so spectacular and they’re so hyped that they become the new go-to and the old ones fade away, but with crabapples there just isn’t that mass appeal anymore,” Veil says. “Maybe Maria [Zampini] is going to change that [with the addition of three crabapple varieties to the Proven Winners Ornamental Trees program]. We’ve got a couple of her new plants here [at Crablandia], but I think putting a crab in a white pot is a start. It’s part of the conversation again.”

Maria Zampini has a family connection to crabapples. Her father, Jim Zampini, was a well-known nurseryman who bred, developed and introduced more than 200 patented or trademarked plants to the industry. He was particularly famous for his crabapples, which include the very fragrant and showy double-flowered pink Brandywine, the diminutive Cinderella, the spreading weeper Molten Lava, the little foliage ball of the top-grafted Lollipop and the large-flowered Madonna.

Jim Zampini passed in 2017. Currently, Maria Zampini, runs Upshoot, Inc., a boutique horticulture marketing firm that specializes in helping breeders introduce their new plants to customers. She also was the person Spring Meadow Nursery, the manager of Proven Winners ColorChoice flowering shrubs, called when they wanted to add ornamental trees to their program.

Chatfield believes that crabapples are gaining popularity again, and Zampini agrees with him.

“They have ups and downs – in favor and out of favor but right now they are on the upswing,” she says.

They are also uniquely positioned to be good “starter trees” for new gardeners that joined the hobby during the pandemic.

“I think as more people garden and become experienced, they understand that modern day crabapples have smaller fruit — which means no mess — are more disease-resistant, come in a variety of sizes, shapes, and colors. That means it can fit in any size landscape, container or in the ground,” she says. “Also it is a tree option that excels not only in the spring but also fall and summer. Gardening and color doesn’t end after spring. So it is a multi-talented tree.”

Another benefit Zampini sees to crabapples is that as more people learn about foodscaping and foraging, they realize that crabapples, depending on the variety, can be a source of food not just for the wildlife and pollinators (which in and of itself is a benefit) but also for humans, too.

The Proven Winners ornamental trees program started with six taxa but has since expanded to 14. Three of those are Maria’s father’s crabapple selections, picked in part to have options for dwarf, intermediate and standard size trees.

Malus Lollipop is dwarf, disease-resistant crabapple with a tight, compact head, prolific white flowers and tiny, red fruit. Malus Show Time is known for its florescent fuchsia-red flowers, red fruit and orange fall foliage. The OSU experts recommend it as an improvement over the venerable ‘Prairifire’ because it boasts similar looks and habit with better disease resistance. Third is Sweet Sugar Tyme, an intermediate-sized crabapple. It is a different tree than its namesake Sugar Tyme which is a standard in size. Sweet Sugar Tyme has smaller fruit than Sugar Tyme.

“This one holds its fruit longer than any other crabapple I’ve ever seen,” Zampini says.

Sweet Sugar Tyme will be in full flower and mummified fruit is still persistent with a dark maroon color and not prune-like in texture so it provides long-lasting, good-looking winter color and interest.

What does the future hold?

Plant popularity comes and goes. And the pendulum may swing back in Malus’ favor soon.

“I think that there may be an opening there where it's almost like how Hydrangea paniculata was dead for 50 years, and now I’ve got 60 varieties growing right over there behind you,” Veil says. “You start with something big and then it leads to more and more.”

Having crabapples attached to the recognizable Proven Winners branding will help, Veil says. With any sales and marketing endeavor, inertia plays a huge role.

“Branding convinces the consumer that there’s something special about this,” he says.

The research and trial work being done at Secrest and elsewhere is accessible, practical science. It’s down-to-earth work. Veil can take traits observed, translate them and tell nursery growers what he found. Even throughout the Midwest, different climates make recommendations difficult. For instance, a crabapple may do well in Chicago but not on the East Coast. The Crablandia trial site aims to provide solid advice for growers from Pittsburgh west to Indiana, north to Michigan and south through the entire Midwest. He hopes others join the mission.

“I think the more places you grow these plants, the better,” Veil says. “Crabs are grown all over the country and it's a big continent where all these plants are going. I tell a lot of visitors ‘the plants don’t read the catalogs.’ The plants don't go on the website and look at ‘how awesome am I supposed to be.’”

Trials will continue to be important, as resistance changes over time. ‘Prairifire’ crabapple aced its disease resistance evaluations for 30 years, with leaves clean of scab even when trees surrounding it had the tell-tale lesions that led to defoliation. But starting in the late ‘90s, it began to exhibit a touch of scab. Now, every spring there is a little more. While ‘Prairifire’ isn’t highly susceptible, it can no longer be considered highly resistant to the newly-evolved strain of the fungus.

And as diseases evolve, others appear, like the Japan apple rust disease discovered at Secrest in 2019. Recognizable for its lipstick-red lesions, the fungus Gymnosporangium yamadae was found for only the third time in North America. Despite it all, Crablandia will endure.

For more: https://secrest.osu.edu/research/crabapples