By Penny Pawl, UC Master Gardener of Napa County
As you drive around Napa Valley at this time of year, you see many beautiful shrubs and trees blooming in a varieties of colors. One standout is crape myrtle (Lagerstroemia), which has been imported from Asia, India and Australia. This plant grows well in our climate and is great to include in a drought-tolerant landscape.
Crape myrtle blossoms may be white, pink, purple, red and shades in between. I like the bark, which tends to peel in the fall. Underneath the outer bark is a smooth bark of smoky brown.
Crape myrtle do not have invasive root systems, which may be one reason they are used as sidewalk margin trees. They don't lift the sidewalks as so many other trees do. And their beautiful fall color is another reward.
Crape myrtles have been grown in China since the Tang dynasty. The Chinese called them the “100 days tree” because its blooms last so long. Another name was “monkey tree” as monkeys could not climb the smooth bark.
I have several crape myrtles growing in my garden. You can easily prune them to different sizes and forms. One of mine is in a long, narrow driveway planter. Over the years, I have cut this plant down and trained it downward so the entire planter is now filled with the plant. It is about two feet tall and eight feet long, it makes a nice display when blooming. I seldom have to water it. Occasionally, I add a few inches of compost.
I've allowed my other crape myrtles to grow to about 10 feet. They are topped during the winter. They flower best on new growth but will flower on old wood.
When you prune crape myrtle, don't chop it down to the ground. Just take the ends of the branches with the seed pods from the old blooms and cut back. Remove any sprouts at the base of the trunk and any unwanted crossing branches. When cutting a branch back, either cut clean with the trunk or a node. Crapes myrtles demand little care other than occasional pruning.
The crape myrtle used for sidewalk trees is L. fauriei species from Japan. This type can reach 30 feet and has small white flowers that are resistant to mildew.
Mildew has never been a problem with the smaller varieties growing in my garden. The Japanese crape myrtle is used to create hybrids with mildew resistance.
Crape myrtles have been in this country since it was founded, imported from India to the Southern U.S. They became very popular but were heavily impacted by powdery mildew. In the 1950s, U.S. Arboretum personnel went to Japan to find mildew-resistant varieties. They brought seeds back with them and started to cross breed. They gave the new plants names from Native American cultures such as Zuni, Tonto and Arapaho. These hybrids are sold at nurseries today.
Experiments with breeding crape myrtle continue in the South. About 10 years ago, breeders debuted a new variety called the Ebony Series, with black leaves and red blooms. Soon one will be growing in my garden because I could not resist.
This plant got its name because of it crinkly flowers and leaves. Sunset's Western Garden Book has almost an entire page dedicated to crape myrtle. It lists the various hybrids with information on size, flowering and mildew resistance. It also lists the zones the plants do the best in. Napa County is Zone 9.
Food Growing Forum: Napa CountyMaster Gardeners will present a discussion of “Perennial Vegetables, Garlic and Alliums” on Sunday, October 10, from 3 p.m. to 4 p.m., via Zoom. Register here to receive the Zoom link.
Free Guided Tree Walk: Join Master Gardeners of Napa County for a tree walk in Fuller Park in Napa on Tuesday, October 12, from 10 a.m. to noon. Limited to 12 people per walk. COVID safety protocols will be followed. You will be asked health questions and asked to sign in. Face masks and social distancing are required. Register here.
Workshop: Napa County Master Gardeners will present a workshop on “Home Vineyard Soil Improvement for Grape Quality and Climate Change” on Sunday, October 23, from 9 a.m. to 12:30 p.m. Learn actions you can take to improve soil health and mitigate climate change. Depending on Covid, this workshop may be conduction in person at a vineyardin Napa, or it may be via Zoom. Register here and you will receive an e-mail a few days before the event with the workshop location or Zoom link.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email. For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
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
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email. For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
By Penny Pawl, UC Master Gardener of Napa County
I have been checking the Farmer's Almanac and other sources like the National Weather Service to try to predict what kind of weather we will have this coming winter. Will it be almost flooding, downpours, freezing or a drought?
According to the Farmer's Almanac, we can expect downpours in November. What to do with all that rainwater? If left to drain into the gutters and storm drains, it just goes back out to sea with many pollutants.
If you build a rain garden, you can divert the water to a location where it can drain back into the soil and be purified at the same time. You can collect rain water from your gutters, rooftop and sidewalk and from the roads. You can collect many acre-feet of water.
For your rain garden, choose a low spot in the yard where water gathers during heavy rains. By enlarging this area and getting it ready for the rainy season, you will conserve a precious resource and use it to make an attractive area in your garden. Many rain-garden plants take little care once established, and their blooms attract pollinators and other good bugs.
Once you have identified the best area for your rain garden, you will need to remove whatever is growing there and lower the elevation by 12 to 14 inches. If your soil drains slowly, put in some type of plastic pipe and gravel in the bottom to help it drain. Add compost and sand to improve drainage. Mix these amendments well with the native soil so that water will drain in 48 hours or less. The plants will help take up the moisture. As with swales, the ground underneath will collect water and keep your plants going during dry seasons.
Once you have the soil prepared, select the plants for your rain garden. You may also want some garden accessories, like a stone or wooden bridge to cross a damp area. There are so many good ideas online that I want to make another rain garden for myself.
Sunset's Western Garden Book has a whole section on water gardens and good plant choices. Some of the recommended plants bloom; others have attractive leaves. Iris will grow well along the edges of the rain garden. Some native grasses also thrive in that environment, as do many ferns. Your rain garden could well become the focal point of your landscape.
If you choose native plants, you will not have to fertilize. These plants evolved in our soils and can get the nutrients they need. Once established, they will need much less water in hot weather as their roots go deep in the soil.
Visit local nurseries to see what they have for rain gardens. You can also do research online or consult books on the subject. The Napa Valley chapter of the California Native Plant Society will have its annual plant sale on Saturday, October 7, and Sunday, October 8, from 10 a.m. to 4 p.m., at Skyline Wilderness Park in Napa. You'll find a selection of native plants that would be excellent for your rain garden.
A lawn can be beautiful with lots of water, fertilizer and herbicide. How much more exciting and environmentally friendly to install a rain garden and make your landscape unique.
Do you want to become a UC Master Gardener of Napa County volunteer? To obtain an application, you must attend an information meeting. For dates, location and times, or to learn more about the program and volunteer commitment, visit the UC Master Gardener of Napa County website.
Workshop: UC Master Gardeners of Napa County will host a guided walk and talk on “Pollinators, Native Plants and Beneficials” on Saturday, September 23, from 9:30 a.m. to 11:30 a.m. at the Martha Walker Garden at Skyline Park in Napa. Any discussion of pollinators would not be complete without some remarks on the bounty of beneficial insects found in everyone's garden. Come see if you can recognize some pollinators and beneficial insects. Online registration (credit card only); Mail-in form (cash or check only)
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/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.
