September 9, 2009

Rain garden

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WRAL reports that early September is the most active time of year for tropical storms. I would welcome a gusher because there has been little rain throughout the summer. I also want to try out my new rain garden.

A rain garden collects water that runs off hard surfaces, such as roofs and driveways, storing and filtering the water to recharge the groundwater. This type of garden needs to be in a particular place, of a particular size, and contain particular plants.

This spring, I bought a book on the topic, Rain Gardening in the South by Helen Kraus and Anne Spafford, which provides instructions, advice and photographs about creating a rain garden. I used the charts in the book to estimate the size of the roof and to determine the size of the rain garden, 10 x 6.



I selected a spot in the backyard about 20 feet from the house, downstream from the downspout at the corner of the house. The site is near the pond and the compost pile, surrounded by several oaks and a hickory. A low area is not ideal, but there were no other options in our heavily wooded yard. The area has standing water at times, but the water drains within 48 hours, even after 5 inches of rain.


The first step is to remove the existing soil. I marked a few plants to be saved. When I started digging out the daylilies, I was surprised to find them shallowly rooted in gray sandy soil. The soil had little organic matter and no worms.

Fortunately, there were no roots from nearby trees. This made digging easier and prevented me from damaging our trees. On the PBS show In the Garden, Bryce Layne said that for the health of a tree, you should not cut any roots larger than your pinkie finger. No danger of that in this particular spot.


Back to the book Rain Gardening in the South. Kraus and Spafford recommended removing all the soil from the hole to a depth of 12 inches. Here I made my first mistake. I found a ruler in the house and brought it outside. I started digging, removing all the soil from the 10 x 6 hole to the depth of the ruler. Later I noticed that the ruler was 14 inches long instead of the standard 12.



After digging out the soil to the proper depth, it was time to stir in the amendments. I had a leftover bag of Black Cow manure and a large pile of compost. I added these amendments at a ratio 2 to 1, soil to amendments. Then I put the soil back into the hole.




By this time, I have been shoveling and amending for 3 days. I remembered reading in Gaia's Garden that old pieces of log would hold water for plants to use during drought, so I buried some limbs of oak trees that had fallen 7 or 8 years ago. This may have been my second mistake. I will find out soon enough.



In the end, the rain garden was 4 inches below grade. I used chunky semi-composted oak leaves from my new compost pile as a 2 inch mulch on the top. Then I formed a berm on the north side of the rain garden.



The following weekend, I was ready to plant. Using the lists of plants in the book, Rain Gardening in the South, I had long ago made a planting plan that was interesting and attractive. I purchased new Illicium plants and planned to transplant Ajuga, Epimedium and ferns from other areas of our garden.



Then I made my final mistake. I went to the plant sale at the NC Botanical Garden and found several that I have been seeking for a long time. I bought twice as many as I had space for, so some of them found a home in the rain garden.

At last it was time for planting. The soil in the rain garden had been resting for seven days. It was rich, dark and moist, perfect for roots of young plants. I was tempted to lie down in it, but I didn't.

Now I am waiting for rain, and lots of it.


1 Comments:

Blogger MarilynJean said...

Meg, I admire your determination and energy, and had to laugh at your desire to lie down in the rich, dark, moist soil, which I would have called dirt. I hope you get lots of rain soon.

September 10, 2009 3:47 PM  

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