A dozen years ago, the three-acre Krasberg Rose Garden would start shutting down soon after Labor Day. That’s changed. “Back then, we were getting ready to pack it in,” says Tom Soulsby, senior horticulturist for the Rose Garden, Heritage Garden, and the Linden Allée. Tom is responsible for curating and maintaining a collection of more than 5,000 roses in one of the largest public rose collections in the country. “There’d be a small flush of blooms in mid-September. But now, with a longer fall, deadheading promotes more blooms.” Deadheading is simply removing faded, spent flowers by cutting them off the plants.

Autumns in the Midwest have been getting warmer over the past several years and Soulsby has no reason to believe that trend will not continue. 

“We continue to care for roses now as we do in June and July—we water, mulch, and keep on top of the deadheading to hopefully get an extended bloom cycle deep into fall.” 

Last year, roses were blooming into November in the Krasberg Rose Garden!

Less is More

Decades ago, some homeowners sprayed their roses throughout summer with a variety of chemicals to prevent leaf spot and insect damage. Come fall, they’d cover their plants with styrofoam rose cones to protect them from freezing temperatures. Those tasks have evolved and now roses require far less maintenance and products have become more environmentally friendly.

“One of our curatorial goals is to dramatically reduce or eliminate that level of care,” Tom says. “We do not use any artificial materials like rose cones and neither should any homeowner. It’s an unnecessary use of plastic and the roses can be too warm inside them.”

Roses need to remain dormant in winter and rose cones can have the opposite effect, tricking the plant into breaking dormancy long before it should. “Most new roses are hardy without winter protection in our area. This saves labor, time, and money. Years ago, we probably cut and covered almost all the roses. Now only a quarter of them require that kind of winter protection.”

Ongoing Changes

Curating the rose collection involves editing. “We had a lot of older roses that weren’t hardy or the best for a Midwest garden—hard to manage, fussy, and they got a bad rap,” Tom says. When the popular Knock Out^® rose was introduced 25 years ago, it sparked a new demand. “It revolutionized the rose business in terms of disease resistance and greater hardiness.” However, gardeners also wanted roses that looked old-fashioned and had fragrance. “Our next focus is as we evaluate roses and do new plantings—if there’s a tie between two different roses and one has fragrance, that’s the one that’s going to win.”  

As a result, the Krasberg Rose Garden is presenting the best plants for Midwest gardens. 

“We want people to be successful, and we work really hard to find some of the newest and best breeding.” There are many newer roses to choose from these days. “Richard Hawke and I participate in the rose evaluation, so we see a lot of things going on with the plants.” 

If you haven’t visited the Mitsuzo and Kyoko Shida Evaluation Garden, this month is a good time to do so. Roses and vines are among some of the many plants undergoing evaluation.

Easing into Autumn

Roses, like other woody plants, need adequate moisture even as the growing season winds down. “Like with any tree or shrub, you’d like to have them well watered going into winter,” Tom says. “I wouldn’t want the ground to be bone dry.”

Although some gardeners might be tempted to cut their roses back to shape them in fall, don’t do it. “Only cut the plant back as needed—if there are broken branches, or if they’re encroaching on a pathway. I try to be very hands off on extensive stem pruning.”

The exceptions are roses that require winter protection. “We cut them back and use composted horse manure on them. The manure is only used on roses that require protection to help them make it through winter.”

Thinking Ahead

Come spring, Tom and Garden staff look for winter dieback and animal damage on rose stems. “We do repair pruning and structural work on the plants in March and April.” Over the years, the Krasberg Rose Garden’s soil has been treated to a lot of organic matter. “The soil is pretty fertile, which is helpful for rose gardening,” Tom says. “In spring, we do a fertilizer treatment as the roses come out of dormancy. Textbook would say to do it after the first major flush of blooms and a month later, but we generally stick with just the first fertilization. And that pushes them along pretty quickly.”

The first spring fertilizer application is a mixture of Milorganite and nitrogen. Milorganite typically is sold in bags at garden centers and big-box stores. It contains heat-dried microbes that have digested organic matter in wastewater. “We occasionally do spot fertilizing for roses that are underperforming in midsummer. It’s fast release with a lot of nitrogen to push a lot of green growth—new leaves, new stems—to set up the structure of the plant to support a lot of blooming power later in the season.” If supplemental nutrients are needed in the summer, a liquid fertilizer is injected into the plant’s root zone.

And while the traditional pastel-colored roses have always charmed, keep an eye out for hot hues next year. “Orange is one of the colors I’m seeing more of coming into the rose collection. It adds a whole other level to the garden.” And that’s something to look forward to.

Nina Koziol is a garden writer and horticulturist who lives and gardens in Palos Park, Illinois.