by Lis Friemoth
Rain, rain, come my way
Here’s how to fill in for Mother Nature
Those of us who garden have an opportunity to shine when it comes to water conservation. To make it easy to figure out ways to go green when working in the green, let’s go over a few things to consider. First, put the right plant in the right place. Second, use responsible care techniques. And third, don’t over-think the obvious.
Right plant, right place — it can be heard frequently but what does it mean? It means thoughtfully choosing plants that can realize their full potential within naturally existing environmental conditions. Creating planting environments that encourage survival outside of the optimal can be useful from a design perspective, but it can also be stressful on the plant material. Stressful growing conditions require more-intense levels of input to maintain — more water, more fertilizer and more human time.
With drought damage from high air temperatures and intense winds being a frequent occurrence for plants in this part of the country, right choice and placement means less water. Do keep in mind that all plants, even drought-resistant ones, need water to get established, especially the first year or two. But, there are some that do very well, with little water after that point.
Be sure to consider all environmental conditions, including soil type, when choosing appropriate plants (see graphic).
Think responsibly about water provision. Make the most of what needs to be done in a timely fashion and do it using responsible techniques. Do you know the water requirements of the plant material in your landscape?
Those needing the most water are, in general, those that have been recently installed or planted. For the first two years after planting, most plant materials require the equivalent of 1 to 2 inches of rainfall per week (soil type and moisture dependent). Water is essential to encouraging healthy root development needed to grow and stabilize the entire plant system.
To mimic 1 inch of rainfall, you need to apply, roughly, 5 gallons of water per square yard of root zone area. If looking to provide enough water to get that 1 inch of rainfall to an 8-inch depth, about 65 gallons per 100 square feet is needed. That translates into about 10 gallons per inch of trunk diameter per tree on small to moderately sized trees. On trees larger than 8 inches in diameter, increase that water to about 15 gallons per inch per tree. A large tree can transpire a lot of water on any day of the year, but during the hot, dry summer, anywhere between 40 to 100 gallons of water can be lost per tree per day.
The best way for plants to receive moisture is from Mother Nature. When we humans need to make up the difference, it should be done deeply, and infrequently, to ensure deep root development and discourage rapid detrimental response to short drought periods. It’s as important to measure and time your application appropriately as it is to apply the water. Different soils absorb water at differing rates, so knowing your soil structure helps to determine water speed.
As a very, very general rule, clay soils will absorb more slowly, often only about 1/4-inch per hour, while soils with more loam content will absorb more quickly — about 1/2-inch per hour. Again, this is very general.
Watering in the evenings is a very relaxing and satisfying way to end the day. That makes us happy; now think about plant needs. Plants lose the most moisture during the day and do most their growing just prior to sunrise, so the best time for plants to receive water is very early in the day. If you are a night waterer, consider changing to early morning. If you are a sprinkler user, consider using soaker hoses or a slow drip system; they are the most effective watering method. After all, the roots are where the action is.
Sprinklers are, in general, big water wasters. When the air is dry and warm, a large percentage of the water that moves through the sprinkler system will evaporate before it hits the ground. However, they are the most effective way to germinate grass seed and keep propagation beds moist. But most plants really don’t need wet foliage to be happy. In fact, there are many potential pathogen issues that can rear up when foliage stays wet for long periods of time, especially when air temperatures are between 50° and 75° F.
Lastly, don’t over-think the obvious; do what’s best. Choose plants that are a good fit for the land. Use the most effective water system available in your price range, and you’ll shorten the time spent on the task and lessen the amount of water used.
Good drought survivors
Acer ginnala, Achillea, Aesclepias, Aesculus, Alcea, Amelanchier, Antennaria, Artemsia, Aster, Betula populifolia, Boltonia, Caryopteris, Celtis occidentalis, Coreopsis, Cotinus coggygria, Dianthus, Echinacea, Echinops, Eupatorium, Gymnocladus dioicus, Hamamelis virginiana, Halesia, Hemerocallis, Lavender, Liatris, Paeonia, Penstemon, Phlox, Perovskia, Sambucus, Sedum, Solidago, Thymus, Tradescantia, Veronica, Viburnum prunifolium, Yucca.
— Lis Friemoth is a horticulture diagnostician. Contact her at (262) 745-2904, P.O. Box 58, Springfield, WI 53176, visit online at www.thegardenhoe.com or e-mail her at gardenhoe@tds.net. Listen to Liz from 9 a.m. to 10 a.m. every third Saturday on WISN AM1130 radio. |
