Wednesday, April 6, 2011


Once again, Blue Jay Barrens seems to be running out of sync with the surrounding area. Plant growth is far behind what it was at this time in 2010 and is noticeably behind what I’m seeing only a few miles away. Even at Blue Jay Barrens there are areas that are displaying growth stages at least a couple of weeks ahead of locations just a few feet away. These places of advanced growth are being influenced by a phenomenon known as a microclimate.
We usually think of climate as the mix of temperatures, rainfall, wind, sun and other factors that dictate the range of our weather patterns. Within the broad climatic area, there are places that diverge from the typical pattern because of geographic features such as mountains or large water bodies. These variations continue on an ever smaller scale until they can be measured in square feet. We’ve reached the realm of the microclimate, within the bounds of which can be found some amazing things.
Although they may not be aware of it, most people are familiar with the influence of a microclimate on plant growth. Daffodils or other early spring flowers making an early start along the south facing foundation of a house is a common occurrence. The house foundation collects and stores heat from the sun and creates an area of warmer soil and ambient air temperatures that stimulates the plants to begin their growth much earlier than their less advantaged counterparts. A less natural example is the cold frame we build to give our garden plants an earlier start.
This section of intermittent stream is an excellent example of a microclimate. Several factors are at work here to make the area slightly warmer and more stable than the surrounding area. A thick Eastern Red Cedar canopy over the stream slows heat loss on clear nights. The high banks shield the area from wind which slows the rate of cooling. The spacing of trees to the south of the site allows the sun to reach the site for most of the day. Water moving around the plants also helps to add extra heat. The result is a growing site that gives the plants a distinct advantage.
This is definitely a site of luxuriant growth. Whether or not this provides a long term survival advantage is another question. Microclimates are everywhere in the landscape. Knowledge of their presence can lead to marvelous discoveries in the field. I pay attention to them constantly and am never disappointed in what they have to offer.


  1. And, surely this is the reason my neighbor's tree down the street is blooming about a week before my tree. Interesting.

  2. Hi that why I seem to always have my daffodils bloom later than other peoples..mine are out in the open area and theirs next to the house !!
    Thanks for the info...I'll use that microclimates explanation on someone about my daffodils, and see if they look at me like I have three heads!!!

  3. Hi, Lois. It's possible that microclimate is cause of the varied blooming times. Another possibility in horticultural and landscape plants is a difference in variety.

    Hi, grammie g. I supposing that the pictures I've seen of you are unaltered and you don't actually have three heads.