by Penny Pawl, UC Master Gardener of Napa County
According to a long-term forecast I heard recently, we may not see substantial rain until April and could be facing drought by summer. With that possibility in mind, you can take steps now to help your plants survive.
First, don't rake up those leaves. They protect the soil, help retain moisture and slowly break down and improve the soil.
I cover my vegetable beds with plain cardboard and leaves for the same purpose. Worms adore cardboard glue and will come to the area, add their manure to the soil and aid the soil bacteria. Worm droppings, also called worm gold, is expensive so it's smart to encourage worms in your garden.
If the cardboard has not completely decomposed when you are ready to plant, just cut a hole in the cardboard for the plant. Several years ago, I did an experiment and planted some plants in plain soil and the rest in holes in cardboard that I laid for that purpose. The ones planted in cardboard did better as the soil retained more moisture.
If you have space, dig a few swales. You can make them artful by putting in curves and planting drought-tolerant plants on the edges. When it rains, runoff will be captured in the swales rather than in the gutter and will slowly percolate into the soil. Ideally, runoff should drain in three days to avoid standing water that attracts mosquitos. And your garden will benefit by having water stored a few feet below the soil surface. Some people fill in their swales with sticks, straw or other material and cover them, but I like to see when the swales are full of rainwater.
Do some research on drought-tolerant plants from other regions of the world with a Mediterranean climate. Also consider California native plants, which have evolved to require little water. About three years ago, I planted Pride of Madeira (Echium candicans), which is native to the island of Madeira. I haven't watered it in two years and it just keeps going. Other choices may not be this hardly and may need water occasionally, especially when first planted.
Group plants with similar water needs so you can irrigate more strategically. Sunset's Western Garden Book can advise you on the water requirements of a plant you're considering. You can also find a chart on the water needs of plants at https://arboretum.ucdavis.edu/arboretum-all-stars
Set up a rain harvesting area. I devised two different systems some years ago and both work well. They are attached to downspouts and collect rainwater for use on my plants. I don't have pumps on either system, but I built them higher than ground level so they drain well. Make sure to use screens or other covers where the water collects to foil mosquitos.
When you do irrigate, water deeply. The feeder roots of most plants are deep in the ground. Water that just penetrates the first few inches of soil won't reach the feeder roots on most plants.
If you're designing a new landscape, choose paths over concrete walkways. Paths allow rainwater to soak into the soil. Choose gravel, bark mulch or steppingstones, all of which allow water to penetrate.
And remember to compost, compost, compost. You can make your own or purchase finished compost. Compost is not a great fertilizer, but it improves soil tilth, so your soil will retain more water. Work compost into the soil. In contrast, materials used for mulch should remain on top of the soil to minimize evaporation, keep the soil cooler and control weeds. Weeds will steal water from plants so controlling weeds is important.
Be sure to deadhead most of your spent flowers, although you may want to leave some to benefit the birds. Setting seed takes energy so a plant that isn't deadheaded may require more water.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. http://ucanr.edu/wildlifehabitat2020
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A few years ago, we heard from Toby Hemenway who wrote Gaia's Garden: A Guide to Home-Scale Permaculture. I studied this book and was very interested in the part he wrote about swales in the garden.
I wanted a habitat garden with native plants in one area of my property. A habitat garden gives small animals places to hide, provides nectar plants for insects and is low maintenance.
I decided that swales were going to be part of this garden since the rainwater needs somewhere to drain. Some swales are filled with twigs and covered with soil, but I wanted my swales to be open so they could be cleaned and so that I could observe what the water was doing. One of my neighbors refers to my swales as “Penny's lakes.”
The ground around the swales has to be saturated from rain before they start to hold water. The water should not remain in the swale more than three days; over that time, it should slowly be absorbed into the soil. The swale creates a damp area where plants can get water during dry periods. My friends are used to me saying,“The swales are full!”
About three years ago, the soil from the swales was mounded and planted with California natives and other low-water-use mediterranean plants. For the first couple of years, I watered them as needed, but last year this area received no water during the entire summer. I may decide to plant some native milkweeds there this fall; if so, I will need to water them next summer.
Mulching is one way to keep plants alive during dry spells. You can mulch with your own compost (if you're not already composting, you can learn to do it in a Master Gardener composting workshop). Or you can buy compost from companies that grind bark and wood into mulch.
After watering the ground well, spread three to four inches of mulch over the soil. You will be amazed how well it keeps water in the soil and available for plants.
Some of the plants I like to use are lavender, lamb's ears, salvias, monkey flower (mimulus), lily-of-the-Nile and yarrow. Some monkey flowers are sticky; others are not. Both types have beautiful flowers in a variety of colors and bloom almost continuously. With a little deadheading they grow right back.
My lavenders have a long bloom period, and bees enjoy them from morning until dusk. Whatever plants you choose, plant them in multiples to make a bigger splash of color and texture.
Local “Cash for Grass” programs are ongoing. You must apply to the City of Napa or American Canyon, and officials will come inspect your grass. Be sure to keep it alive until then. If approved, you will receive a grant to replace your grass. Then you can proceed with plans to create a habitat garden, dry garden, succulent garden or other garden of your choosing.
Walk your neighborhood to see what others have done. Peruse books for design ideas and visit local nurseries for plant suggestions.Gather information before you start.
You don't have to tear out your lawn. You can cover it with large pieces of clean cardboard, and then cover the cardboard with lots of mulch. Worms and other micro organisms will eat the cardboard and decompose it for you. In a few months you will have a dead lawn and some good soil to plant in.
If you're resourceful, drought does not mean the end of your landscape; it just means a different way of doing things.
Workshop: Napa County Master Gardeners will lead a workshop on “Drought-Tolerant and California Native Plants” on Saturday, August 1, from 9:30 a.m. to 11:30 a.m., at Martha Walker Garden in Skyline Park in Napa. Enjoy a walk around the garden to observe drought-tolerant and native plants, and discover the elements that help them thrive in our Mediterranean climate. Learn how to use them in your own garden to replace some of those water-hungry ornamentals.On-line registration (credit card only) Mail-in registration (cash or check only)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners ( http://ucanr.org/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.