Earlier blooming and spreading pests offer evidence of warming trend

Plants are blooming and experiencing leaf budding earlier in public gardens throughout the United States and some plant species, including weeds, are growing in areas they never grew before. Ominously, plant pests are also being seen in new areas.

You won’t find details of these phenomena in the National Oceanic and Atmospheric Administration (NOAA) planting zone maps, but you will learn about the “new normals.”

Scientists at NOAA are trying to match their expertise on climate and how climate is changing over time with biologists who can talk about how landscapes are adapting to a changing climate. NOAA’s map indicates slight changes in climate-related planting zones based on trends from 1971 to 2010, and here is what they forecast the zones will look like over the next 30 years if the same trend continues.
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“When looking at the Climate-Related Planting Zone Maps, one thing that stands out is that the planting zones are shifting northwards, which impacts the types of plant species that can grow in those zones,” says Tamara Houston, sectoral engagement coordinator for NOAA’s National Climatic Data Center.

“We continue to see increased warming of the planet because of climate change,” says Lubchenco, adding that there will be more wild weather swings to come, including more drought and more floods.

NOAA’s climate services and the American Public Gardens Association (APGA) are jointly conducting a pilot project at Longwood Gardens in Kennett Square, Pa., to educate the public about the possible effects of climate change on America’s green spaces. The project uses NOAA climate data to show how average annual minimum temperature changes affect climate-related planting zones. The information is geared to help landscape contractors, farmers and gardeners identify which plant species will best survive in certain conditions.

“There is telling evidence that climate change is affecting plant life around the world and here at Longwood. Through Longwood Gardens-sponsored research, we have observed that plants are flowering earlier on average one day per decade over the last 150 years,” says Paul Redman, director of Longwood Gardens.

The pilot project is the first of five projects the partnership has established to meet its goals.

“It primarily serves as an instant resource about climate change to make people aware of the bigger issue that not only is our climate changing, but part of that is bringing home to people the types of plants we grow or even have and maintain naturally are going to be changing as a result of our shifting climate patterns,” says Dr. Casey Sclar, interim executive director of APGA and a former plant health care leader for Longwood Gardens.

“It becomes real challenging, especially for a grounds manager, to become better educated about how to best maintain the grounds, the best plants and species of turf to use, and then wonder about what to do in terms of rainfall, either more or less, for example,” he says.

Phillips says the goal is to network with other public gardens nationwide about the implications for local conditions.

Pests on the march

The second project entails a cooperative agreement between APGA and the USDA Animal and Plant Health Inspection Service (APHIS) to develop training programs for public gardens to educate visitors to become first detectors of emerging pests and diseases in plants, focusing on species of high risk, as the range and relative impact of pests and diseases changes with the climate.

AGPA has partnered with NOAA to develop climate change curricula, cell phone tours and other materials. One small part of that project includes working a climate change component into the Sentinel Plant Network high-risk pest training program.

“What we’re seeing now are introduced pests we thought would have limited climatic distribution patterns. Based on that, we thought we would be able to regulate them,” Sclar says.

Case in point: the hemlock woolly adelgid, a pest found along the Eastern Seaboard. “I’ve seen that move more southern and more northern in its distribution than a lot of people thought possible,” says Sclar. “When you look at longer-term distribution patterns, for a time it held where it was for maybe a decade, and then it spread.

“Another one is the brown marmorated stink bug that’s moving from one place to another. In some ways, it’s just fulfilling its distribution pattern,” says Sclar.

In terms of turfgrass pests, the European crane fly continues to spread to new areas, and the distribution of the Oriental beetle is shifting as well, he adds. The shift is subtle but ongoing.

Getting the word out

The third, and a big part of the project, involves APGA hosting a series of community dialogs at member gardens with civic and industry leaders to discuss environmental and economic impacts of climate variability on communities and businesses.

“It’s very tough for the average person to get their hands around climate change,” says Sclar. “It’s been as much of a political debate as a scientific debate, so the question I always get from people is: ‘You say our climate is changing. How does that impact me? What things can I do?’

“There’s a huge economic impact to climate change. Anybody who’s done storm cleanup knows about climate change and its impact. Here in the mid-Atlantic region, we’re seeing two major variables of importance. There are more temperature extremes each year: the hots are hotter, the colds are colder.

“There’s also increased precipitation, particularly in the form of downpour events. The average number of storm events that have more than 2 inches of water a year associated with it is on the rise, and that has huge stormwater implications for us,” says Sclar.

There is a “suite” of actions people can take to reduce their climate impacts, Sclar says. “A turf manager can increase the company’s operational efficiencies so trucks are spending less time on the road,” he says. “They can look at alternative energy equipment on the leading edge. All of this is pointed at an overall carbon footprint reduction.”

Against this backdrop, turf managers must consider how turf is maintained, the level of aesthetics desired and the equipment, water, pesticides and fertilizers it takes to maintain it, Sclar says.

“Here in the mid-Atlantic, we have some greater lower maintenance turfgrasses – hard, red and other fescue blends. They’re not no-maintenance, but the number of yearly passes they need to take with a mower is fewer, so you burn less fossil fuels.”

National effort needed

The fourth – and a capstone – project entails a national summit on the role of science-based cultural institutions, such as gardens, zoos and technology centers, to increase climate change literacy.

In support of that would be the development of a climate change curriculum for public garden professionals offered through APGA that would also identify professionals to be trained to offer such programs on a regional basis.

“Climate change is a global problem, but it’s going to be experienced regionally,” Sclar notes.

“By understanding that fact, combined with increased stormwater issues, a grounds manager is in a much better capacity to understand what the challenges are going to be in their existing landscapes and can better inform their clients on what to be prepared for – what plants are going to be successful at their site.”

Climate change will take landscape contractors’ businesses in a different direction, Sclar says. More companies may be involved in storm cleanup or may be using their equipment for more snowplowing a couple of extra weeks a year. Another area of opportunity for grounds managers and turf professionals going forward is capturing rainwater for reuse, not just on a residential scale, but on a commercial scale, too.

Ultimately, one of the factors landscape contractors should consider is whether one plants for the conditions of yesterday or for tomorrow, says Phillips.

Carol Brzozowski resides in Coral Springs, Fla., is a member of the Society of Environmental Journalists and has written extensively about environmental issues for more than a decade. She can be reached at Brozozowski@aol.com.