Xerophobia: Fear of drought

27 May 2009

In The Garden With the Fluvanna Master Gardeners
By Irene C. Burke - Fluvanna Master Gardener
Fluvanna County Extension Office: 434.591.1950

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A 2005 article in "Environmental Management," showed that about 40 million U.S. acres are irrigated turf, more than four times the amount used to irrigate corn. Water is the issue, not just turf. Let us now talk water-wise gardening.

Soil preparation

With soil preparation key to efficient and effective gardening, plan to incorporate organic material with native soil at a one-to-one ratio for large beds---10’X10’ or more. A bathtub effect will sink and drown your efforts within three years, if you use the same ratio for one small planting hole.

Mulch

Maintain a four-inch depth of organic mulch, three inches from the base of the planting. For large trees mulch four to six inches deep, six inches from the base flare, out to the drip line. Organic material amends and nourishes the clay, encouraging beneficial soil organisms to lighten the structure with the humus they create.

Choose organic mulch for most plants. However, stone, gravel or crushed shells serve plants needing cool roots and alkaline soil with reflected light, like rosemary, lavender and clematis.

Tolerance

Select plants that demonstrate heat, drought and wind tolerance. Tolerance indicates adaptation not preference, where the plant retreats to dormancy or succulence when stressed by a diminished water supply.

Air circulation

Provide space for air circulation for random cool, wet spells when opportunistic fungi strike.

Ground covers

Minimize turf and combat erosion on steep slopes with varied ground covers and slope-hugging shrubs. Stay away from monocultures and landscape boredom.

Irrigation

Reduce overhead watering with a drip system using five gallon buckets with holes in the base and flat-bottomed ooze hoses. Time irrigation for early morning. Avoid splash or runoff to paved surfaces. Invest in rain barrels and roll-up plastic rain bags fitted to downspouts.

Plant grouping

Moisture lovers should reside together near the water source or in the wettest part of your garden. Desert dwellers belong in the sunniest quarter.

Wind

Reduce harsh wind effects with latticed fencing or hedges. Solid walls create a down draft on the leeward side scouring soil and vegetation. If options are few, save the area for dry shade plants.

Dry shade

Dry shade presents a double challenge, limited water and sunlight, usually under trees and house eaves. Search the Web for comprehensive lists. Try Liriope spicata, Pachysandra terminalis, Vinca minor, Lily-of-the-Valley, Christmas fern, Hypericum calycinum, Lambs ears, Mock Orange, Ginko biloba, and Scotch pine.

Rain garden

The latest term for those boggy zones is "rain garden," typically an area subject to intermittent flooding. Native species will do best in your rain garden.

Sun exposure and length

As surface temperatures rise through the day, track morning and afternoon sun exposure from northeast to southwest. Choose plants accordingly. Along with exposure, note the number of sunlight hours. Six seems to be the agreed cut-off between full and partial.

Culture practices

Remove weeds gently. Mulch the resulting bare spots. Water all plants, shrubs and trees thoroughly, ONLY until established. Double-pot containers with the outer pot holding a covered water reservoir just below the roots’ reach. Do not fertilize during dry spells.

Tip of the Week

Bluegill, crappie, perch, and trout, love red worms, so does your compost pile. Add two-dozen red "trout" worms (Eisenia foetida) to the eight-inch perimeter of your compost pile away from the hot center. Filling stations, hardware and country stores carry them. The price is right and the effect long lasting because red worms multiply rapidly.