Tuesday, March 27, 2012

Phenology in the Garden

Bulbs, mostly from plants that originally grew in snowy alpine regions, can handle the vicissitudes of spring and provide welcome colors to northern climates in early spring!

Spring Update:
Spring is rapidly proceeding across the country, with high temperatures still breaking records in much of the northern US. Here in the Rockies plants are blooming an average of 2-4 weeks earlier than normal. The dry La Nina winter has been warm and dry in the Colorado Front Range, leading to a series of fires this last week and early but not lush vegetation growth. Black bears are already coming out of hibernation! Just this last week tulips, grape hyacinths and other garden bulbs have started flowering, green ashes are in bloom now and crabapples and plums are covered with white or pinkish blooms. Forsythia is in full bloom now. All are about 3 weeks early this year. We are having day after day of temperatures in the 70's or even 80's, whereas normal is closer to 50-60 degrees.

Cherry Blossom Blitz: Reports are beginning to trickle in of chokecherries, sweet cherries, and Japanese cherries beginning to bud out or to bloom, first in the south, but more in northern areas as well. In my yard the sweet cherries and the chokecherries have swelling buds this week. Every day new plants become active -- its the best time of the year to be watching plants!

Phenology in the Garden
This time of the year, as garden soils are thawing out, and budding plants are everywhere it's a good time to consider another value to knowing when plants start budding out or sending out their first flowers. Phenology is an ancient science, and was practiced long before there was much scientific understanding of what clues plants use to determine when to start their spring growth. For early agriculturists it was a matter of survival. Phenology was used to determine when to plant crops, and to time other activities on farms or ranches.

For gardeners and homeowners today phenology can be used to determine when to start various treatments in lawns or gardens, and are much more accurate than using some general date on the calendar. For example when Forsythia is in bloom is often used to indicate when to start worrying about treating weed seeds in lawns. Soils need to reach about 35 degrees before seeds of lettuce and onion may be expected to germinate. This temperature can be determined by which species of wildflower are active. Flowering of dandelions can be used to estimate this time period. Some other examples of how phenology can be used in the garden:
plant potatoes when dandelions are in bloom
transplant melons and peppers when irises are in bloom
plant tomatoes when lily of the valley (Convallaria majalis) is in full bloom.

Of course like a lot of hints provided to complex phenomena in nature the devil is in the details. These rules of thumb vary depending on where you live, and the specifics of your home or garden. But you can see that if you keep careful records on the phenology of your garden as well as wilder places around you, you can develop your own rules for when to do various tasks in the yard or garden. As our weather and climate continues to gyrate wildly from year to year these clues may become a lot more useful than the typical generic guidelines you see in gardening publications.

Project Budburst is all about becoming closely connected with and in touch with your local environment. This knowledge can have practical advantages too!

Paul Alaback

More examples of garden phenology

Tuesday, March 20, 2012

Happy Cherry Blossom Blitz!

Photo courtesy of Ashley Bradford
As we celebrate the first day of spring and the launch of our spring campaign, “Cherry Blossom Blitz,” it seems like spring got a head start in much of the country!  I had hoped to catch the Washington DC cherry blossoms at peak when I visit there late next week, but saw several news pieces over the weekend telling me I’ll be a little late.  Last night, the early bloom of the tidal basin cherry trees caught the attention of the “PBS NewsHour” with a piece featuring Dr. Soo-HyungKim, a colleague from University of Washington who is studying cherry phenology and has used Project BudBurst data for some of his work.  He projects cherry trees could be blooming in late February in Washington DC toward the end of the century if the Intergovernmental Panel on Climate Change (IPCC) climate scenarios play out as predicted.

Meanwhile, here in Chicago we continue to break temperature and phenological records.  We also have ornamental cherries (Prunus spp.) in bloom, as well as flowering quince (Chaenomeles speciosa), and even some early tulips (Tulipa spp.).  We typically see tulips blooming around Mother’s Day!  Redbuds (Cercis canadensis) are just coming into bloom, as are white trout lilies (Erythronium albidum). The crabapples (Malus spp.) and Juneberries (Amelanchier spp.) are in bud and not far behind.  And as a sure sign of spring, tonight I’ll harvest the first batch of asparagus out of the garden for dinner! 

Please let us know what’s happening in your neighborhood!  Are you experiencing a remarkably early spring also?

Kay Havens-Young 

Thursday, March 15, 2012

Spring is just around the corner--even in Chicago!

By: Dr. Kayri Havens, Director of Plant Science and Conservation, Chicago Botanic Garden

I heard this morning that our “winter that wasn’t” was the 4th warmest on record. So say the statistics kept by NOAA (National Oceanic and Atmospheric Administration) for the lower 48 states for the period December-February. Based on records going back to the 1890s, only the winters of 1991-1992, 1998-1999, 1999-2000 were warmer. For Illinois, it was our 3rd warmest winter on record. All of this indicates that if it is not spring in your neighborhood yet, it will be soon!

We’ve just had two unseasonably warm days (upper 60s) and the signs of spring are popping up everywhere. Buds are swelling, catkins are elongating and the weeping willows are starting their spring progression from brown to yellow-green to green. The snowdrops, hellebores and first crocuses have been blooming for some time. Bright yellow groupings of witch hazel shrubs light up the drab landscape. The foliage of many bulbs is well out of the ground and the flower buds on the early daffodils are almost ready to open. Pussy willows are looking furry and red maples are beginning to bloom. Outside my office, I’m seeing male red-winged blackbirds setting up their territories and hearing the cardinals start to sing. What’s happening in your neighborhood?

Photo courtesy of Chicago Botanic Garden: Daffodils in bloom at the Chicago Botanic Garden March 2012