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 email@example.com 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.
I was raised in the desert, in a landscape with more cactus than trees. So I especially appreciate the many trees that thrive in Napa Valley. On a hot summer day, it's a joy to be able to hang out under a tree in the shade. Several varieties are particularly suited for local home and patios.
One of my favorite patio-suitable trees is the Japanese maple (Acer palmatum). With a maximum 30-foot height and 30-foot spread, it's a yard-friendly tree. The leaves turn bright orange in autumn, another feature I love. I don't need to do much decorating at Thanksgiving because we usually have a tree or two ablaze with color. And because maples are deciduous, our trees let lots of light into our home during the dreary winter months.
Another attractive tree for the home landscape is the summer-blooming crape myrtle (Lagerstroemia indica). With an average height of 30 feet and average 20-foot spread, it's a good choice for patios. You can see crape myrtles in bloom around Napa in shades of lavender, pink, red and white. They are a popular street tree because their roots don't break up sidewalks. The median islands along California Street in Napa are planted with red-blooming crape myrtles.
Once established, this lovely tree is drought tolerant, a key consideration these days. Crape myrtles also put on a show in autumn when their leaves turn orange, red and yellow before dropping. Fortunately, the leaves are small and don't clog storm drains. The mottled bark on the trunk adds to the tree's beauty as the older gray bark peels back to reveal new reddish-brown bark underneath.
According to John Hoffman's Trees to Know in the Napa Valley, the Ginkgo biloba is a “gardener's dream, requiring little pruning and resisting most insects and diseases . . . thriving under adverse growing conditions.” Reaching 70 feet in height and 40 feet in width, this large tree tolerates just about anything urban life can throw at it, including polluted air and cramped space.
This resilience is pretty amazing because the ginkgo is literally a living fossil. Also known as maidenhair tree, it has a history of survival. The leaf looks the same today as in fossils found in China from 270 million years ago.
Six ginkgo trees near the center of the blast survived the bombing of Hiroshima. After that, the ginkgo tree became known as the “bearer of hope,” its leaf used as a symbol of hope and peace. Its unique fan-shaped leaf turns bright yellow in the fall.
One note of caution: If you decide to plant one of these distinctive trees, make sure it is a male. While the fruit of the female is valued in Chinese cooking, it makes a mess when it drops and it smells horrible.
These three trees and twelve others are considered by Napa County Master Gardeners to be star performers in the Napa Valley. In addition to thriving in our Mediterranean climate and clay soil, these trees have attractive qualities that make them great choices for home gardens, public streets and parks.
Workshop: U. C. Master Gardeners of Napa County will conduct a workshop on “Landscape Tree Appreciation and Care” on Wednesday, July 20, from 6 p.m. to 7:30 p.m., in the Napa County Library Community Room. Learn how landscape trees enhance our lives, how to choose the best trees for your site and how to keep your trees healthy.
The talk will be followed by an optional guided tree walk at Fuller Park in Napa from 8 p.m. to 9 p.m. The walk will be repeated on Saturday, July 23, from 9 a.m. to 10:30 a.m. There is no fee for the workshop or tree walk. For more information, call the Napa County Library at 707-299-1481 or U.C. Master Gardeners at 707-253-4140.
Guided Tree Walk: Join U. C. Master Gardeners of Napa County for a free guided tree walk through Napa's Fuller Park on Monday, July 11, from 10 a.m. to 11:30 a.m. There is no charge for the walk but registration is recommended as space is limited. Meet at the corner of Jefferson and Oak Streets. Online registration or call 707-253-4221. Trees to Know in Napa Valleywill be available to purchase for $15 each. Cash or check payable to UC Regents. Sorry, we are unable to process credit cards.
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.