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Pieris rapae, Pieris rapae, Pieris rapae...

A cabbage white butterfly, Pieris rapae, nectaring on catmint last summer in Vacaville. (Too late in the season last year to win Art Shapiro's contest.) (Photo by Kathy Keatley Garvey)

"Today dawned foggy," began Art Shapiro, distinguished professor of evolution and ecology, in a Jan. 22nd group email. As you know, Shapiro sponsors...

A cabbage white butterfly, Pieris rapae, nectaring on catmint last summer in Vacaville. (Too late in the season last year to win Art Shapiro's contest.) (Photo by Kathy Keatley Garvey)
A cabbage white butterfly, Pieris rapae, nectaring on catmint last summer in Vacaville. (Too late in the season last year to win Art Shapiro's contest.) (Photo by Kathy Keatley Garvey)

A cabbage white butterfly, Pieris rapae, nectaring on catmint last summer in Vacaville. (Too late in the season last year to win Art Shapiro's contest.) (Photo by Kathy Keatley Garvey)

Spotted Spurge Scourge

Spotted Spurge (Euphorbia (=Chamaesyce) maculata) is a garden weed that can seem impossible to control. It grows rapidly and starts producing seeds at a very small size. A large plant can produce thousands of seeds. If you pull the weed and leave it lying in the garden, many of the seeds left on the plant will be jumping off to your garden soil before you gather it up for disposal. Spurge seeds will likely emerge from the compost bin still viable, and most gardening sites recommend you exclude all weed seeds from composting. Other weeds that may survive the composting process are oxalis bulbs and the seeds of burclover, amaranth, and cheeseweed.)

Spotted Spurge usually, but not always, has a red or maroon colored spot in the middle of its small oval leaves. The reddish stems contain a milky juice that can cause irritation to skin and eyes upon contact. It grows like a mat, close to the ground which can reach 3 feet across. Aside from growing on any spot of bare soil no matter how poor, in is just as happy to take up residence in a crack in your sidewalk, Seeds form in a tiny triangular pod containing 3 seeds. You may not be able to see these without magnification. The plant can be found in our area from February through September, and seeds begin germination with temperatures reach 60 degrees.

Other names for this plant include Spotted Euphorbia, Spotted Sandmat, and Prostrate Spurge. There are other related forms of Spurge that are not as much of a garden pest. However, some of these spread by roots and may be considered invasive. These include Petty Spurge, Nodding Spurge, and Leafy Spurge (Euphorbia esula). The latter comes in many colorful varieties and is often found in seed or plant catalogs.

The best way to outmaneuver spotted spurge is to pull it by hand when it is small or use a thick mulch, to prevent or discourage its germination. There are commercial sprays that will kill the plant, but the plant will still need to be hand-pulled, wearing gloves, to keep those remaining seeds from being left in the plant's footprint. For the driveway or sidewalks, this is one application where a flame weeder /garden torch could be considered.

Folklore about spurge concerns the milky juice in the stems, which has been claimed to remove warts. Here is one such story. “When I was a very young boy (about 5 years old) I went to a gypsy camp close to Bodmin (Cornwall, England). There was a lady there complaining that the gypsy lady had failed to ‘charm' a very disfiguring wart on her face. The gypsy said she had another way provided she was given silver. Wartweed was produced and the ‘milk' applied to the wart, and she was told to do this daily. The husband refused to pay. The gypsy then cursed him and rubbed his forehead with wartweed. Later that day we saw the husband in Bodmin and there was a bright red cross on his forehead.”

 

For further information, go to the UC-IPM web site at:

http://ipm.ucanr.edu/PMG/WEEDS/spotted_spurge.html

 

 

Small spurge plant. (photo by David Bellamy)
Small spurge plant. (photo by David Bellamy)

Posted on Friday, January 24, 2020 at 9:57 AM

A Troubling Question: Why Are the Monarchs Declining in the West?

A male monarch nectaring on Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

The question is troubling: What's going on with the monarch butterfly population in the West? The Xerces Society for Invertebrate Conservation...

A male monarch nectaring on Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)
A male monarch nectaring on Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

A male monarch nectaring on Mexican sunflower (Tithonia) in Vacaville, Calif. (Photo by Kathy Keatley Garvey)

A monarch sipping nectar from its host plant, milkweed. (Photo by Kathy Keatley Garvey)
A monarch sipping nectar from its host plant, milkweed. (Photo by Kathy Keatley Garvey)

A monarch sipping nectar from its host plant, milkweed. (Photo by Kathy Keatley Garvey)

Bulbs: It's Not Too Late to Plant Them

Even in the middle of winter, we know that spring can't be far behind.  We see those delicious leaves from the bulbs we planted years ago just push up and out of the soil and our first hope of that welcome, warmer season dares to fill us with wonder and expectation.

But, all this color and promise takes a bit of forethought.  While our local nurseries tell us that the time to plant our bulbs is in the fall in order to reap the benefits of spring bulbs, with a bit of planning, we can have the magic of bulbs poking up and flowering in our gardens all growing season long.

Bulbs are among the easiest plants to grow.  By carefully selecting varieties with a range of bloom times, our gardens can broadcast color from spring through fall. 

Before we go further, we need to recognize that what we call “bulbs”, actually fall into six categories:

  1. THE TRUE BULB: a swollen, underground stem on a solid, compact fleshy stem—(basal plate), surrounded by fleshy leaves or scales that protect and store food for the embryonic plant.  The outer scales are dry and form a papery covering or “tunic”. Examples are amaryllis, daffodil, Dutch iris, hyacinth, muscari, lily and tulip.
  2. RHIZOME: A thickened, horizontal stem which grows partially or completely underground.  The roots grow from the underside and the main growing area is the tip—although some growing points may form along the rhizomes' length.  Rhizomes include bearded iris, canna, and calla lily.
  3. CORM: A swollen, underground stem base of solid tissue—which is different than a bulb's scales—with a basal plate from which roots grow.  The growth point is on the top of the corm and they have “tunics” consisting of dried bases from the previous year's growth.  Corms include crocus, freesia, gladiolus, ranunculus, and watsonia.
  4. TUBER:  a swollen, underground stem base with no basal plate, or compact fleshy stem. Their roots grow from all sides and there are multiple eyes or buds distributed over the upper surface, where the plants emerge.  Examples are begonia, cyclamen, and anemone.
  5. TUBEROUS ROOT: thickened roots that specialize in storing nutrients.  Growth buds are at the bases of the old stems rather than on the tuberous roots. Dahlias are tuberous roots.
  6. FLESHY ROOT: nutrients are stored in the fleshy roots.  Peony and daylily are fleshy roots.

Now that we know the differences, we can understand that fall isn't the only time to plant our “bulbs”.

We can begin planting right now in January and February and beyond!

Here are—A-Z--some examples of what and when we should plant each of the six categories described above and, most wonderfully, when we can expect to see “the blooms of our labor”.

  • Amaryllis-naked lady-- bulb: plant in February for summer bloom.
  • Begonia—tuber:  plant March-May for bloom summer-fall bloom.
  • Calla—rhizome:  plant through April for spring-summer bloom.
  • Crocosmia—corm: plant in February for spring-summer bloom.
  • Dahlia—tuberous root: plant February-May for summer-fall bloom.
  • Gladiolus—corm: plant February-April for Spring-fall bloom.
  • Lily—bulb: plant February-March for summer-fall bloom.
  • Tuberose—rhizome: plant February-April for summer-fall bloom.
  • Epharanthes: bulb: plant anytime for summer-fall bloom.

 I, for one, am off to start the New Year by planting more “bulbs” in anticipation of the surprise of those underground wonders popping up with their riot of color almost all year long.

Dahlia. photo by Jennifer Baumbach
Dahlia. photo by Jennifer Baumbach

Posted on Thursday, January 23, 2020 at 4:16 PM

Untreatable fungus giving almond producers pause

An airborne fungus from Europe, ganoderma adspersum, has been killing almond trees in the San Jaoquin Valley since it was discovered in the area five years ago, reported John Cox in the Bakersfield Californian.

The fungus rots wood from the inside out, usually weakening the trunk a ground level. 

Three kinds of ganoderma fungus infections were identified recently in California almond orchards; University of California researchers say 94 percent of the cases were of the adspersum variety.

"We are seeing those trees collapsing at 11, 12, 15 years old,” said UC Cooperative Extension orchard systems advisor Mohammad Yaghmour. The infections have results in the removal of orchards at less than half their typical 20- to 25-year life span.

Spraying for the fungal disease is ineffective. Yaghmour believes that in time researchers will identify a root stock that is resistant to the fungus.

A fallen almond tree that was weakened by Ganoderma fungus. (Photo: Bob Johnson)
 
 
Posted on Thursday, January 23, 2020 at 9:19 AM
Tags: almonds (61), ganoderma (2), Mohammad Yaghmour (3)

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