Even Mother Nature procrastinates. Or at least this year she's gone back to bed and pulled the blanket over her head. She is wisely waiting for warmer days. The spring of 2014 has been slow to arrive and our plants are showing the effects. In my estimation we are two to three weeks behind schedule in plant growth. In contrast the early warm spring weather of 2012 created a sudden burst of blooms and the daffodils were finishing their flourish of flowers by mid-April. This year mine are finally showing a hint of future flowers. However as I gawk over garden gates around town some daffodils are in full bloom. So what's the difference? Are my daffodils just slow achievers?
Actually it's all about Mother Nature and microclimates. A microclimate is an area of the yard that differs significantly from the environmental conditions of the remaining landscape. Differences could be warmer or cooler; wetter or drier; and windier or calmer. Courtyards are obvious examples of microclimates. They offer protection from wind and the warming effects of nearby structures. Microclimates are often due to their proximity to structures such as fences, houses, garages, patios, sidewalks and driveways. Structures warm faster and retain heat longer than soil. Nearby structures help to warm the surrounding soil, hence daffodils and other plants develop and emerge earlier in the spring.
Urban areas create a widespread microclimate. Cities with their heat collecting rooftops, parking lots and pavements tend to have less extreme low temperatures in winter and warmer soils than the surrounding rural area where I live. Buildings and paved surfaces absorb heat during the day and then radiate it back into the air at night which can reduce the chances of frost and moderate low temperatures during winter.
In summer the other side of this warming effect becomes apparent as cities become heat islands. Urban microclimates can trap heat which can create a scorching environment for us and our plants.
Buildings may also offer protection from wind but can also create wind tunnels. If you have ever walked down a Chicago city sidewalk, the effects of wind tunnels are obvious as you try to stay upright.
We can use microclimates to grow plants that may be marginally winter hardy here. Gardeners are known for their zonal envy as we gravitate to plants rated to a warmer zone. Our northwesterly winter winds create a warmer, more sheltered microclimate on the south and east sides of our houses. It's the perfect spot for your coveted plant winter hardiness trials and fulfillment of your zonal envy.
We also create microclimates when we mulch with shredded leaves or bark mulch. Mulch moderates soil temperatures, keeping them warmer in winter and cooler in summer. Raised beds also create microclimates as the soil warms and dries faster in spring making for quicker planting in spring.
Look around your landscape now. Which plants are progressing faster than their neighbors? You may be seeing the effects of a microclimate.
Cornell University Extension offers more detailed information about microclimates http://www.gardening.cornell.edu/weather/microcli.html
Join Master Naturalists on Monday April 21, 2014 at 6:30 p.m. at UI Extension auditorium 801 North Country Fair Drive; Champaign, IL for a program about one of the most misunderstood weather phenomena - Lightning.
Presenter Dr. Eric Snodgrass, Director of Undergraduate Studies in the Department of Atmospheric Sciences, University of Illinois will dispel lightning myths, while sharing how lightning forms, what types of clouds produce lightning, and how clouds can build up such enormous electrical charge. Stunning photos and videos of cloud-to-ground lightning strikes will illustrate how these massive sparks of electricity choose their path through the atmosphere. Special emphasis on lightning safety will be highlighted as the spring thunderstorm season begins. No fee or registration required. For more information PH: 217.333.7672 http://web.extension.illinois.edu/cfiv/