We’ve seen it all this spring. Below-freezing cold snaps one day followed by 86 degree sunshine the next. Weeks of drought, then a two-week spate of cloudbursts. Wind. Hail. Even a few snowflakes.
No doubt about it, the spring weather for the past few years has been, to put it politely, capricious. But with an April 15 typical last frost date in the rearview mirror, it’s worth looking at some things that may help gardeners cope with Kansas City’s challenges.
Climate changes have been a big driver of lasting gardening trends, say seed sellers and horticulture experts in the area. Fall gardens are becoming more popular for the cooler-weather plants, for instance. And there continues to be an effort to put more drought-tolerant plants in the ground for those extra hot and windy summers.
Kansas City’s weather has been changing, as evidenced by its redesignation five years ago in the U.S. Department of Agriculture hardiness zone. Kansas City was previously in Zone 5, with coldest winter temperatures occasionally touching 20 degrees below zero. Now the area is in Zone 6, with the coldest temperature at minus 10.
According to the National Oceanic and Atmospheric Administration, annual mean temperatures in Kansas and Missouri have been climbing since 1975.
That warmth has meant that plants that formerly might not have been considered for this area now do better. Crepe myrtle is a good example, said Dennis Patton, horticulture agent at the K-State Research and Extension service. People planting crepe myrtle in past years risked having it die back to the ground every winter. Now that’s not always the case.
But it’s too early yet for gardeners to count on always getting good results with borderline plants like crepe myrtle. A lot depends on consistency, a weather trait Kansas City often lacks. Things may look good for the tender plants when November and December are warm, but then plummet off a cliff when there’s a sudden cold snap, he said.
It’s not just the warmth, either. Crazy swings in rainfall also have gardeners pulling out their hair.
“It’s definitely feast or famine when it comes to rainfall,” Patton said, noting that we didn’t have a good soaking rain from last fall until a few weeks ago. “But then when it turns back on, it just doesn’t stop.”
Maybe that could account for one trend he has noticed: a growing acceptance of native plants. “There are 10 to 20 different plants native to Kansas City that are more dependable to these kinds of swings,” he said.
Liatris, echinaceas, some milkweeds and butterfly bush are now considered garden-worthy, and native grasses like switch grasses, little bluestem and prairie dropseed are all coming in style, he said.
Uneven rainfall can be a headache for flowers, said Robin Ruether, flower trials manager at the K-State Olathe Horticulture Research & Extension Center. The center tests flowers and vegetables for companies by giving them typical growing conditions that they’d experience in a Kansas City yard.
Often, flowers look good in May, only to get a sudden 2 or 3 inches of rain saturating the soil in early June. That’s a problem for plants like petunias, which are sensitive to waterlogged soil, Ruether said.
Seed companies have been building more drought tolerance into their plants for years. Now they are also looking for better tolerance to wide weather swings, she said. They’ve had some success with a new canna “cannova” that can handle saturated soil but also loves the heat, she said. “It’s important to choose adaptable or resilient flowers.”
Vendors also have been interested in marketing flowers with a dual purpose, she said. “They may be attractive but also help pollinators, or attractive but also edible, like ornamental basils or peppers,” she said. That keeps things new and also feeds gardeners’ desire for something that will grow well and bloom all summer.
“It’s so hard to keep marketing a new color of petunia because there are just so many petunias out there already,” she said.
Those abrupt changes from early spring cool to summer hot mean gardeners may have to adjust not only what they plant, but when they plant it, say gardening experts in the area. Garden staples like spinach and some lettuce, for example, will stop growing the tasty leaves and shoot up a seed spire when the weather gets too hot. But if the spring stays extra cool, the seeds may not germinate fast enough to get big enough before that happens. That’s why spring has become more problematic in this area.
Instead of giving up on spring crops, though, they suggest a late summer planting for a fall crop, especially now that the first frost seems to be coming later.
“In my own garden, sweet peas and snow peas and cool-season plants are a better crop to grow in the fall now than the spring because it gets hot so much quicker than it used to,” said Kathy McFarland, spokeswoman for Baker Creek Heirloom Seeds in Mansfield, Mo.
There are other ways of getting around the spring weather problem. When hot, dry weather makes it too hard to germinate cool season crops, Claire Zimmermann, farm and food project developer for Cultivate Kansas City, suggests starting transplants indoors.
Milder winters also mean that overwintering plants can be more successful than in years past, Zimmermann said. That spinach, for example, could be mulched to protect it from the lowest temperatures.
Overwintering is “easier and easier because we have less and less sustained below-freezing temperatures,” she said. In fact, she has had spinach, perennial herbs and kale survive a recent winter without being mulched at all.
Gardeners who still want spring crops can have them, with careful attention to maturity dates, said Cary Rivard, fruit and vegetable specialist at the K-State research center in Olathe. Vegetables like broccoli, cabbage and cauliflower typically favor cooler temperatures. Fewer days to maturity — information that can be found on the seed packet or greenhouse marker — will limit the risk of failure, he said.
The weather isn’t the only thing concerning gardeners this year. Local plant experts report a big interest in helping pollinators like bees, butterflies and hummingbirds.
“I get that question probably every day: ‘What can I plant that will help the bees?’ ” McFarland said. Such plants as butterfly bush and some milkweeds are becoming more sought after as a way to help the declining pollinator populations.
That’s evident in the types of flowers being tested as well, Ruether said. And the native plants also include something for the pollinators.
Gardeners will always push the boundaries with plants and shrubs that thrive better in other climates. Niche plants will always struggle. Success will depend on how closely the conditions match what the plant likes, Patton said.
“It all gets back to the right plant in the right place with proper maintenance,” he said.
▪ The Missouri Prairie Foundation (moprairie.org) has a wealth of links and resources, including a list of top 10 native plants.
▪ The research center run by Kansas State University in Olathe (prairiestarflowers.com) has an online list of flowers tested for this area.
▪ K-State Extension also carries a list of recommended plants at hnr.k-state.edu/extension/info-center/recommended-plants.