Rain Garden Plants

Ciscoe Morris: String trimmers can harm trees

Ciscoe's picks

This is a family-friendly community planting event to build 10 rain gardens to protect Longfellow Creek. Meet at 5424 25th Ave. S.W., Seattle.

Fabulous Fronderosa Frolic 2011: 10 a.m.-3 p.m. Saturday and Sunday. A festival of rare plants, garden art, artifacts and botanical conversations with some of the Northwest's premier specialty growers and garden artists. It takes place at Fancy Fronds in Gold Bar. Directions and information: www.fancyfronds.com/frolic.cfm .

Fifth annual Highline Botanical Garden Foundation Ice Cream Social: 1 p.m. Sunday. There also will be a silent auction, a plant sale and door prizes galore. The first 300 guests will enjoy free ice cream. I will be speaking at 2:30 p.m. The garden is located at 13735 24th Ave S. in SeaTac. More information about the garden and the event: www.highlinegarden.org .

Q: The people who mow my lawn use string trimmers around the base of the trees. Is that a good practice, or could it be harmful to my trees?

A: I am a certified arborist. One of the problems I've often observed over the years is decay at the base of trees caused by string trimmers. Especially in young trees with thin bark, even the most skilled string-trimmer operator can't avoid making tiny cuts that often lead to long-term problems.

To prevent the need to trim around the tree, remove the sod growing immediately around it. Studies found that grass roots emit a substance harmful to tree roots, and keeping the turf at least 6 inches away results in significantly increased root development and improved vigor.

Use a digging spade to scrape away the sod from within at least 6 inches of the trunk. Avoid slicing into the roots, and use a sharp pruner to cut off any that are damaged in the process.

Mulch with wood chips to discourage grass from growing back, but don't let the mulch build up around the trunk. Then ask the folks on the mowing crew to do a quick weeding of the mulched area, rather than running the trimmer. This method looks great and is much better for your trees.

Q: I've heard you should no longer use tires to grow root vegetables because of possible health problems. I grew some tomato plants in old tires. Is it safe to eat the tomatoes?

I Want To Read About » Rain Gardens

Article by Oz Gardener

Background

Rain gardens are planned gardens that capture, and filter, rain water that would otherwise run off, or through, your property.

Runoff is a serious problem where increased development has replaced land with impervious surfaces … roads, roofs, patios, etc. that preclude rainwater from soaking into the ground.

Problems Associated with Rainwater Runoff

Pollution of streams and water supplies as rainwater picks up chemicals from roads, lawns, farms, and parking lots

Erosion of surface soil and subsoil, sometimes resulting in sinkholes and structural damage

Reduction of replenishment of groundwater supplies

Benefits of Rain Gardens

You’ll help the local environment and improve the beauty of your immediate surroundings. Once established, rain gardens are nearly maintenance-free and very attractive.

The Basics

1. Locate your rain gardens at least 10 feet from your house to prevent water accumulation around your foundation.

2. Don’t put it immediately over a septic system.

3. Your rain garden should be 4 to 8 inches lower than the surrounding surface of the lawn, to trap rainwater for a short period of time, allowing it to seep into the soil

Plan Your Rain Garden

Select a location where water runs off or through your property.

Then, decide how big your rain garden should be.

For very sandy soil, plan on 20% of the total area of impervious surface.

For loamy soil, the area should be about 35%.

For heavy clay soil, your garden may need to be 50% of the impenetrable area.

Second, decide the shape. Shapes similar to squares and ovals work better; long, skinny gardens won’t capture much runoff.

Third, decide what to plant. Experts recommend “native” plants, because they will thrive in your climate. For specific recommendations, you can Google “Rain Garden Plants for [your state].”

How to Build Your Rain Garden

First, remove the sod from the area, roots and all.

Second, add compost, which will significantly improve both the fertility and tilth of the soil. The Mantis tiller is especially good at mixing compost into the soil. For more on compost, visit http://www.thegardenofoz.org/composting101.asp or http://www.howtocompost.org/

Third, plant “native plants”. You can include trees and shrubs, which will develop large root systems and absorb a lot of water.

Rain garden plants, purchase or propagate?

Organic Gardening

Rain gardening in the South, ecologically designed gardens for drought, deluge, and everything in between

Organic housekeeping, in which the Nontoxic Avenger shows you how to improve your health and that of your family while you save time, money, and, perhaps your sanity

High-Impact, Low-Carbon Gardening