Changing Weather Patterns
From Wet Spring to Drought and Back Again

How many growing seasons have been just perfect for planting these last few years? How often have you been able to accurately predict the last frost of the season, allowing you to plant immediately without worry of a freeze? And then there are the droughts - have they impacted the beauty (or survival) of your gardens these last few summers?

The good news is that these changing weather patterns have resulted in a more creative, adaptable group of gardeners in South Central Pennsylvania. We have learned that we can keep our plants hydrated by catching water that might have formerly been wasted and that there are some pretty resilient, drought-tolerant plants. And in recent weeks, we have seen how high winds and thunderstorms can flatten a beautifully blooming garden at its peak!

We hear quite a bit about the jet stream - "a high-speed, wandering wind current (at least 57 mph) in the upper atmosphere that blows from west to east and affects weather". At an altitude of about 20,000 feet (6-9 miles) above earth's surface, the jet stream is at the top of the earth's troposphere where most weather occurs. The core of the jet stream reaches an average windspeed of about 92 mph and can reach 300 mph in winter. These winds are stronger in the winter because the surface temperature contrasts are greater.

Although the jet stream may stretch for thousands of miles around the world, it is only a few hundred miles wide and often less than 3 miles thick. This strong current of air pushes weather systems around the world, and greatly affects local weather patterns by propelling them forward.

Especially interesting is the manner in which the jet stream affects weather worldwide. In the event of an eastward shift in warm Pacific water (known as an El NiZo), the atmosphere's energy balance is changed. Warm ocean water supplies both moisture and energy for huge thunderstorms.

These thunderstorms feed both moisture and wind energy into the upper atmosphere, where they influence jet stream winds. When the warm water and thunderstorms move eastward, they help change the jet stream. These changes, in turn, move storms on different paths than usual, upsetting normal patterns of wet and dry weather.

While the unusually cool, wet spring of 2003 served to delay the growing season, our plantings finally began to grow when the sun began to shine for extended periods of time. In contrast, a growing season with too little rain will have a significant, negative impact on most plants.

In preparation for future drought conditions, it may make sense to incorporate a few plants that are adaptable to dry conditions. In our area, where drought conditions are cyclical in nature but inevitable, you may want to consider the following plants that will flourish in dry conditions once they are established in your garden:

Hopefully, our summer plantings will enjoy a steady flow of moisture as needed this year. However, when selecting plants for next year's garden, you may want to be prepared for whatever the jet stream brings. If drought tolerance is a goal in your garden, try planting a few selections from the list above. You can have constant color regardless in spite of what could turn out to be drought conditions here in South Central Pennsylvania.

Read other articles on gardening in drought conditions

Read other summer related gardening articles