- Author: Jeanne Lawrence, UC Master Gardener of Butte County
Given the right conditions, some seemingly mild-mannered plants can become garden thugs, invading entire yards and even moving on to the rest of the neighborhood. We may all have heard stories about the bamboo or mint that threatened to take over a garden, but there are other potentially nasty plants lurking out there. In the interest of saving others from the anguish of dealing with unexpectedly invasive plants, our local Master Gardeners (MGs) volunteer the following tales of their own (often on-going) battles with particular members of the plant kingdom.
Morning glories have proven to be tenacious fighters in many gardens. In particular, the perennial morning glory (often labeled “Heavenly Blue” or “Blue Dawn Flower”) can cover entire buildings, and grows so fast you'd swear you could see it growing while you watched it. One Chico MG reports that it took years to eradicate it from her yard – vines were still emerging in her shady side yard ten years after she had dug it up from the roots in an attempt to permanently dispose of it. A Durham MG had the same experience.
More than one MG in Chico has engaged in battle with Mexican feather grass Stipa tenuissima (formerly known as Nasella tenuissima). They were attracted to the way its flower stalks “shimmy” so charmingly in the breeze. But that lovely movement with the wind aids the plant's dissemination. One feather grass victim notes that “after a couple of years I noticed small seedlings in many places around my lot. As the plant is drought tolerant, the seedlings did well even if they didn't receive any supplemental irrigation. Where there was supplemental irrigation, they were especially plentiful. After about a year of constantly pulling unwanted seedlings, I finally removed the mother plants. Three years later, I'm still pulling unwanted seedlings.” Another MG notes that “in Chico, it can take over the neighborhood, especially where bare ground is showing.”
Russian Sage has proven to be very invasive in the Chapmantown yard of a Chico MG, who reports that “it sends up shoots the full length of my house.” Trying to keep it contained by cutting it just encourages the plant to send up more shoots.
Shady Chico yards provide the ideal conditions for the spread of a nearly evergreen species of alstroemeria, the Peruvian Lily A. psittacina. Its dark red flowers marked with green and blotched with dark purple appear in early summer and early fall; the two-foot-tall foliage provides useful ground cover during the winter and dies back in mid-summer. But don't be fooled! Over time this alstroemeria will move into every shady area in a yard and even colonize sunnier locations. It travels by tuberous rhizomes which develop in clusters. Because it is impossible to dig up every single tuber in these clusters, the plant is impossible to eradicate. A Chico MG with a very shady yard knows she will be battling this ultra-vigorous plant for the rest of her life.
Up in Paradise, an MG planted one yellow flag iris (pseudacrus) ten years ago in a semi-shady location with spring water available all year. She now has an area eight feet long and four feet wide filled with these plants, which die to the ground in cold weather. “The roots are enormous,” she says, adding that “it would require a back hoe to dig them out.”
The bottom line: Think twice (or three times) before planting these potential garden invaders!
For a list of common invasive plants and some suggested alternatives to them, go to the PlantRight website.
UC Master Gardeners of Butte County are part of the University of California Cooperative Extension (UCCE) system. To learn more about us and our upcoming events, and for help with gardening in our area, visit our website. If you have a gardening question or problem, email the Hotline at mgbutte@ucanr.edu (preferred) or call (530) 538-7201.
- Author: Christine Casey
Our understanding of Russian sage's native habitat remains unchanged. It's still not from Russia, but is native to grassland areas in western China, Pakistan, and Afghanistan. These hot, dry, sunny areas have summer weather similar to California's Central Valley so it does well in our gardens.
Here are links to some of the scientific papers describing these changes for those who wish to learn more:
Salvia yangii. National Center for Biotechnology Information. Link here.
Taxon. 2017. Salvia united: The greatest good for the greatest number. Read here.
American Journal of Botany. 2012. Phylogenetics, biogeography, and staminal evolution in the tribe Mentheae (Lamiaceae). Read here.
Please consider supporting our Crowdfund UC Davis campaign. We rely on donations and grants to keep the Haven and this blog going to share accurate, science-based information about bees and gardens. Thank you!
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By Denise Seghesio Levine, U.C. Master Gardener of Napa County
To pinch or not to pinch? That is the question. Pinching is a technique that can shape a plant; increase production of herbs, flowers and fruits; determine the size of blooms and fruit and even keep your garden blooming longer. But pinching is not the answer for every plant. So which plants should you pinch, and how?
Pinching is a form of pruning. You can do it with no other tool than your fingertips and fingernails, although if you have a lot of pinching to do, clean scissors or shears will save your manicure. By “pinching,” I mean actually removing the new tender growth at the end of a stem.
Pinch as close to leaf nodes as possible, being careful not to injure the tiny buds beneath. Each time you remove a main stem, your plant will try to grow two new stems beneath the pinch or cut. This easy technique encourages fullness and also helps keep plant size in check. It forces most plants to grow bushier and fuller rather than concentrating their energy on getting taller.
Basil, tarragon, thyme, sage, scented geraniums and marigolds respond well to pinching. Oregano and thyme do best when pinched or cut back to about half their length. Frequent pinching can keep rosemary and lavender to a manageable size during their spring growth spurt and supply you with lots of herbs for cooking. Cut back woody stems by no more than one-third.
With most herbs, the more you pinch, the more you will have. For a summer-long harvest of Genovese or Thai basil, pinch.
Inspect the base of the leaves where they connect to the stem and you will see new leaves forming in tiny pairs. Pinch right above that point and soon each pair of leaves will turn into a new branch. This practice keeps your plant producing leaves rather than going into flower and seed mode. Remember to feed your culinary herbs and keep them watered so they will work hard for you.
Many flowers benefit from pinching or cutting, rewarding you with armloads of blooms. But it's worth getting to know the few flowers that do not like this treatment because an unwelcome pinch can eliminate your entire harvest for the season. Do not pinch campanula, cockscomb, delphinium, dill, stock, larkspur and most sunflowers.
Do pinch annuals such as coleus, impatiens, salvia, most snapdragons and petunias early in the season to encourage bushing and spreading. Pinching encourages more side branches, which means more flowers and color for your garden or pots.
Always pinch at a node but decide how low to pinch depending on how compact you want the plant to be. Sweet peas will branch into a much fuller plant with pinching. When you are happy with your plants' shape, stop pinching and let them grow.
Zinnias and cosmos are especially generous bloomers if pinched. Pinch early to promote branching, then “pinch” by cutting flowers. The more frequently you pick bouquets, the more flowers you will have for your tables and your friends. It is a beautiful thing.
Each time you pinch a plant, you delay its flowering. The result is a plant with more side shoots but smaller flowers. With chrysanthemums you can decide if you want a few large flowers or many smaller ones. If you prefer dinner plate-size blossoms, remove side shoots and laterals early in the season when they are green and succulent, leaving only the few stems you want to bloom.
You can stagger bloom times with some late-flowering plants like Russian sage, phlox and asters by pinching back half of the plants in your flower bed by about one third. The pinched plants will bloom later, giving you a few more weeks of summer beauty.
Remove peony blossoms when they are finished so the plant can focus energy on next year's blossoms instead of producing seed. Clip foxglove after blooming to have healthy flowers next year or forego pinching them and let them self-seed. You will probably have fewer blossoms next year but potentially more plants.
Refrain from pinching if you want blossoms and seeds for local birds and insects. As a compromise position, let the last, late blooms go to seed, or identify a few plants as your seed producers for pollinators, birds and self-seeding.
Workshop: U. C. Master Gardeners of Napa County will conduct a workshop on “Make Room for Salvias” on Saturday, April 21, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension office, 1710 Soscol Avenue, Napa. Every gardener should be able to find a salvia just right for that little (or big) space. Salvias are long-lasting, attract butterflies and pollinators and have attractive foliage. Learn how to select and care for these versatile plants.Online registration (credit card only);Mail-in/Walk-in registration (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.
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- Author: Kathy Keatley Garvey
Pull up a lawn chair and watch the honey bees.
They're buzzing around the Russian sage, gathering nectar. So focused are they that they don't seeem to mind the photographer sharing their space. So dedicated. So committed. So industrious.
Wait, a honey bee is wearing a new hat. Wait, another is playing peek-a-bee.
It's a great time to be in the garden.
![A honey bee visiting a Russian sage seems to be wearing a new hat. (Photo by Kathy Keatley Garvey) A honey bee visiting a Russian sage seems to be wearing a new hat. (Photo by Kathy Keatley Garvey)](/blogs/blogcore/blogfiles/890.jpg)
![A honey bee aims straight for the Russian sage. Her eye catches the photographer. Who's more focused? The bee or the photographer? (Photo by Kathy Keatley Garvey) A honey bee aims straight for the Russian sage. Her eye catches the photographer. Who's more focused? The bee or the photographer? (Photo by Kathy Keatley Garvey)](/blogs/blogcore/blogfiles/891.jpg)