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European Honeybee ( Apis mellifera ) approaching Purple Sage ( Salvia leucophylla ) Bees, butterflies, moths and other insects – we ...

Sunday, June 25, 2017

Help! The Leaves on My Evergreen Toyon (Ceanothus, Coffeeberry, etc.) are Turning Yellow!

 
Yellowing leaves on California coffeeberry (Frangula californica)

It’s May, June or early July.  The days are warm and the garden’s transitioning from spring to summer.  Suddenly, you notice yellow leaves on your evergreen shrubs.  If the shrubs have been thriving all spring, the appearance of yellow leaves can be surprising and alarming.

Take a deep breath.  Then carefully examine your shrub.  Are the yellow leaves larger and older?  Lower on the branches (closer to the trunk)?  Are the yellow leaves scattered throughout the foliage (not concentrated on a single branch)?   Are healthy new leaves emerging?  If so, your shrub is likely exhibiting a normal seasonal process – summer leaf drop.
 
Note that the larger, older leaves are yellowing
 on this 'Ray Hartman' ceanothus
 
 Evergreen plants lose their leaves, just like deciduous plants.  But they lose them less frequently – and not all-at-once.  Shedding old leaves is but one way that woody plants conserve their resources.  Old leaves are often less productive. They are also more likely to be unhealthy.  In short, senescent leaves become a drain on the plant. They simply require more resources than they make, an unfavorable cost-benefit ratio.

And so, evergreen plants shed their old leaves, but not haphazardly.  They usually recycle mineral nutrients and plant chemicals before they jettison an old leaf.  The declining leaf then produces less green chlorophyll, becomes yellow (or orange) and ultimately separates from the branch at a special site called the abscission layer.  The process is relatively safe and painless for the plant; the abscission layer ‘walls off’ the leaf scar on the branch, preventing disease.   And the senescent leaf simply drops off – its work complete.

Older toyon leaf turning yellow & red.  Note disease.
 
Evergreen plants drop their old leaves at different times of the year. Some lose them, a little at a time, throughout the year.  But many large California native shrubs, particularly those from the chaparral, lose their leaves in late spring/early summer, before the dry season begins in earnest. This allows them to channel their energy into summer growth and drought avoidance.  So summer leaf drop is perfectly coordinated with our challenging mediterranean climate.

Coffeeberry leaves provide summer leaf color.
 
So what’s a gardener to do?  If you have a big garden event that requires an immaculate garden (a garden wedding?  a visit from the queen?) then gently remove the leaves just prior to the event.  This will improve the appearance and won’t harm the plant.  Otherwise, sit back and let nature take her course.

Enjoy a bit of ‘summer leaf color’.  Let the leaves fall naturally, creating a native leaf mulch to support your many soil creatures. Savor the yearly changes associated with our natural heritage.  Summer leaf drop is, after all, part of the cycle of seasons in a California native garden.
 

 

 

 
We welcome your comments (below).  You can also send your questions to: mothernaturesbackyard10@gmail.com

 

 

Thursday, June 15, 2017

Celebrate National Pollinator Week (June 19-25, 2017)




Ten years ago, the U.S. senate designated one week in June as National Pollinator Week. Like Earth Day, National Pollinator week celebrates one of our countries greatest resources – its pollinators.   Living pollinators enable 80% of the earth’s plant species to reproduce.  Included are many of the fruits, nuts, seeds and grains we eat.  Our world would be a very different place without pollinators!

One purpose of National Pollinator Week is to educate all Americans about the diversity and importance of our native pollinators.  Another purpose is to motivate us to take action. So take a little time this week to celebrate the great diversity of our California pollinators.  Here are a few simple actions you can take: 

1.   Visit the National Pollinator Week website: http://www.pollinator.org/pollinatorweek/

 
2.   Participate in a local Pollinator Week activity

 
3.   Learn about local native pollinators: a good place to start is: http://mother-natures-backyard.blogspot.com/2016/07/insect-postings-mother-natures-backyard.html
 

4.   Plant a pollinator habitat plant: if you live in S. California (or other place with hot, dry summers) you may want to wait to purchase and plant until next fall/winter.  But choose a habitat plant or two (those native to your area are best) and dedicate a part of your garden to pollinator habitat.  Learn more at:

 





 
5.   Photograph pollinators, in your garden or in the wilds. Then upload your photos to iNaturalist (https://www.inaturalist.org/) to add to our knowledge of native pollinators.   You might even discover a new species in the process!!

 

Wednesday, June 7, 2017

Plant of the Month (June) : Cliff spurge – Euphorbia misera



Cliff spurge (Euphorbia misera): Mother Nature's Garden of Health

 
There’s not much blooming that we haven’t already featured as a Plant of the Month.  So we’ve chosen a plant that’s as well known for its form as for its flowers.  Our Cliff spurge is looking nice in a large pot in Mother Nature’s Garden of Health. The scientific name is pronounced: you-FOR-bee-uh  MIZ-er-uh.

Cliff spurge, also known as California spurge, is a part-woody sub-shrub native to Southern California and the states of Baja California and Sonora, Mexico.  It is one of those interesting local natives that can be found along the coast as well as in the Sonoran Desert – both in Mexico and in the U.S. 

Primarily a Mexican species, this plant’s northern limit is the Channel Islands of Los Angeles County (both Santa Catalina and San Clemente Islands).  It still also grows in isolated pockets along the coastal bluffs of Orange and San Diego Counties.  It inhabits rocky or sandy, south facing slopes in the coastal scrub, coastal bluff scrub and Sonoran desert scrub communities.   Rare and threatened by development and frequent fires in California [1,2], its status is more secure, at least thus far, in Mexico.

Cliff spurge (Euphorbia misera): young plant
 
Cliff spurge belongs to the spurge family (Euphorbiaceae), a large and interesting group growing mostly in temperate and tropical zones.  Some members – like the Cliff spurge – are succulent and many have milky sap that contains latex.  A number also have medicinal properties (many are poisonous as well).   In addition to the genus Euphorbia (many native and non-native species), this family includes California natives like California copperleaf (Acalypha) and Croton.  Also members of the spurge family are the non-native poinsettia (Euphorbia pulcherrima), cassava (Manihot esculenta) and castor oil plant (Ricinus communis).
 

Cliff spurge (Euphorbia misera): branches and bark
 
Cliff spurge has many characteristics of the Euphorbiaceae.  It grows 2-5 ft. (1-1.5 m.) tall and about as wide.  It has an open, irregularly branching form – somewhat mounded overall.  Its branches are succulent, part-woody and covered with a pale gray-tan bark. The young branches are hairy, but they become smooth with age.  The plant looks rather like an ancient miniature tree; and it has been put to such uses by bonsai artists.
 
Cliff spurge (Euphorbia misera): leaves
 

The leaves of Euphorbia misera have very short petioles (leaf stems) and appear almost haphazardly spaced along the branches.  The leaves are simple, rounded and medium green.  They have a distinctive fold along the midrib (like a taco shell) and often have very narrow stipules (small, leaf-like appendages from the petiole).  The plant leafs out with the winter rains; the leaves are lost in the dry season.  In the wilds (or in a dry garden) the plants can remain leafless for half of the year. Despite this, the plants are surprisingly attractive, due to their remarkable form.


Cliff spurge (Euphorbia misera): spring

Cliff spurge (Euphorbia misera): fall

 
Many Euphorbias have unusual flowers; Euphorbia misera is no exception.  The flowers comprise a specialized structure, known as the cyathium.  The simple male flowers are contained within the cup of the cyathium (see the pollen-laden anthers in the photo below).  The female flower, with its swollen ovary, is on a stalk above the male flowers.  The ovary becomes a wrinkled, lobed fruit which contains the wrinkled, gray seed.   

Nectar glands in the cup of the cyathium (purple-red in Euphorbia misera) produce nectar, attracting bees, butterflies and hummingbirds.  The major pollinators are likely insects.  We’ll try to keep an eye on this plant when it’s flowering to see if we can add more details.

Cliff spurge (Euphorbia misera): flowers
 


Cliff spurge (Euphorbia misera): close-up view of flower


Cliff spurge can bloom any time of the year.  It flowers after rain events in its native setting, and will bloom off and on from spring through summer in a garden.  But the flowers are small; most gardeners who choose this species are either Euphorb enthusiasts, are interested in rare natives, or are captivated by its unusual form.  We confess to being all of the above!

Euphorbia misera is slow-growing, making it a natural for a large container.  It can take full sun near the coast; afternoon shade is best further inland.  It likes a well-drained, sandy or rocky soil.  If you have clay, try planting it atop a low berm to improve drainage.  In containers, we just use an organic potting mix (unamended).  Try to get one without much added manure – this plant doesn’t need lots of nutrients.  In the ground it needs no fertilizer; in containers, try a ½ strength dose in late winter.

Cliff spurge is drought tolerant once established, but looks a bit better with occasional summer rain.  This plant gets summer (monsoonal) rain in its native range.  It can take monthly (or even a bit more) summer irrigation in well-drained soils. Our unglazed terra cotta pots dry out quickly, so we water our container-grown pot at least weekly in hot, windy weather. 

Cliff spurge (Euphorbia misera): young plant
 
Euphorbia misera has a picturesque natural shape. Some gardeners just let it take its natural form.   If you want to shape it, try selective pruning in late fall.  You’ll want to wear gloves and be sure to not get the milky latex on your skin. Many people are allergic to it. Also, never eat any part of this plant – it’s toxic.  

An infusion of the roots of Cliff spurge was traditionally used in the treatment of stomach aches, dysentery and venereal diseases.  One would want to know more about the dosing and preparation of this plant before using it medicinally.  Remember that this plant, along with many other Euphorbs, can be poisonous. 

Cliff spurge looks nice when planted with its natural associates, including coast spicebush (Cneoridium dumosum), California boxthorn (Lycium californicum), California sagebrush (Artemisia californica), lemonade berry (Rhus integrifolia), bladderpod (Isomeris arborea) and ladies’ fingers dudleya (Dudleya edulis).  We particularly love the look of it in a large container.  Cliff spurge looks right at home in a Mediterranean or Central American-style garden.  You could even combine it with Euphorbs from around the world, to create a garden celebrating this incredible Family!

Cliff spurge (Euphorbia misera): leafed out, Mother Nature's Garden of Health,
Gardena Willows Wetland Preserve, Gardena CA
 



For plant information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html

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We welcome your comments (below).  You can also send your questions to: mothernaturesbackyard10@gmail.com

 

Friday, May 19, 2017

Flame Skimmer Dragonfly – Libellula saturata

Flame Skimmer - Libellula saturata (female): perched, hunting

The warm weather of late spring brings many interesting insects to S. California gardens.  Among the most fascinating are the dragonflies.  From May through fall, dragonflies may be seen in any garden providing insects for them to eat.  One of the more common – at least in western Los Angeles County - is the Flame Skimmer, Libellula saturata.  The scientific name for this species is pronounced lie-BELL-you-luh  sat-you-RAY-tuh.

Dragonflies and the closely-related damselflies are carnivorous insects in the order Odonata.  The odonates are an ancient group of insects: fossil dragonflies are  documented from well before the time of the dinosaurs (early ancestors from the Carboniferous Period).  At that time, some odonates were huge, with wingspans several feet wide.  Today’s dragonflies are smaller, but still have some of the prehistoric characteristics that make them ‘living fossils’.

Dragonflies have several notable characteristics.  First they have relatively large heads, equipped with large, compound eyes.  In fact, dragonfly vision is among the best in the world.  Dragonflies also have two sets of elongated wings, which allow them to maneuver in flight in astounding ways.

Like many insects, dragonflies go through several developmental stages before reaching adulthood.  True to their ancient lineage, the juvenile forms (nymphs) are aquatic or semi-aquatic.  Eggs are laid in water, on vegetation near water or in other moist places.  That’s why dragonflies are commonly seen around ponds, pools, marshes and slow-moving streams.   If you have dragonflies in your garden, there likely is a water source nearby.

Flame Skimmers (Libellula saturata) and Neon Skimmers:
Rancho Santa Ana Botanic Garden. Claremont CA
 
Flame skimmers are among the larger local dragonflies.  They belong to the family Libellulidae – the Skimmers – the largest dragonfly family, with over 1000 species.  This family includes dragonflies that hunt for prey while flying, as well as those who perch and wait for prey.  The Flame skimmer is one of the latter, making it relatively easy to photograph. 

Flame Skimmers are native to western U.S. from ID and WY to California, TX and northern Mexico.  Adults range in size from 2-3 inches (5-7.5 cm) long.  The males are entirely bright orange, including their body, eye, legs and wings.  We don’t have good photographs of a male, but recommend the excellent images from references 1 and 2, below.     The only local species that are remotely similar are the Neon Skimmer (more brilliant red in color) and the Cardinal Meadowhawk (usually only seen in the mountains in our area).

Flame Skimmer - Libellula saturata (female):
 
Females (above) are a lighter, browner orange (or even brown) with yellow markings.  Their wings have less of an orange tint than do the males (male wings are orange to ½ their width).  The females also have a conspicuous swelling on the 7th section of their abdomen (see arrow on photo above).

Adults will eat almost any soft-bodied flying insect including mosquitoes, flies, butterflies, moths, mayflies, and flying ants or termites.  In short, they are good natural pest control agents – although they also eat butterflies and other pollinators. Flame Skimmers hunt by perching on a rock or upright branch to wait for prey. They’re always on the alert for big, scary creatures (like you), as well as their next meal.  They then dart out to catch the hapless insect.  Watching them hunt is fascinating! 

Flame Skimmers lay their eggs in warm water.  That’s why they are often seen near shallow ponds, lakes, slow-moving streams, warm marshes and even hot springs.     Males are often seen cruising such site, which they defend from other males. The adults mate during the primary flight season (May-September). After mating, females lay their eggs by dipping their abdomens into the water, releasing the eggs.

Flame Skimmer - Libellula saturata (female): this species
 perches to hunt
 
The immature nymphs (naiads) live in mud on the bottom of warm ponds, streams, and springs. Like the adults, they wait for their prey to pass by, affording them protection from other predators.   The nymphs become quite large (over 1 inch (28 mm) long) and look like a stocky, hairy insect, with a rounded abdomen.  We don’t have any naiad photos, but recommend those in references 3 and 4, below.   If you run into them when cleaning your pond, just release them back into the mud.

Naiads feed on a wide variety of aquatic insects, such as mosquito larvae, other aquatic fly larvae, mayfly larvae, and freshwater shrimp. They will also eat small fish and tadpoles.   When mature, the adults emerge at night.

Flame Skimmers (Libellula saturata; males) perched and Neon Skimmers (flying):
 Rancho Santa Ana Botanic Garden. Claremont CA
 

Watch for these colorful dragonflies in your summer garden.  Try to get some good pictures, and upload them to the iNaturalist site (https://www.inaturalist.org/).  If you have a pond, you might even be lucky enough to see a nymph!

 
 

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We encourage your comments below.   If you have questions about Duskywing butterflies or other gardening topics you can e-mail us at :  mothernaturesbackyard10@gmail.com
 
 
 

Tuesday, May 9, 2017

Plant of the Month (May) : California brodiaea – Brodiaea californica


California brodiaea (Brodiaea californica) : Mother Nature's Backyard 


The parade of native ‘bulbs’ continues to unfold in S. California gardens.  From the early-blooming Red-skinned onion and Blue dicks, to the late-blooming Tritelias and Brodiaeas, there’s usually something of interest from January through May.  Right now the star geophyte is the California brodiaea, Brodiaea californica [pronounced bro-DEE-uh  cal-ih-FOR-ni-cuh]. 

As its name suggests, California brodiaea is endemic to California, gracing the foothills and meadows of the North Coastal Ranges and northern Sierra Nevadas.  It grows in gravelly, clay soils or serpentine, in the grassland, open woodland and chaparral communities, up to about 3000 ft. (900 m.) elevation.  But it grows surprisingly well in a range of garden soils and climates, making it a staple perennial in local gardens.   It is variously placed in the Lilliacieae or the Themidaceae, along with the California native Bloomeria, Dichelostema, Muilla and Triteleia. 

California brodiaea (Brodiaea californica) : corms
 
Brodiaea californica is a corm-producing perennial.  It dies back to its underground storage organ (the corm) after producing seeds.  The corm is rounded and has coarse, brown fibers (see above).   The plants remain dormant until the winter rains, when the stems begin to grow again.  The plants first produce several leaves; then, with the warmer weather, they quickly send up flowering stalks and begin to flower.  In our S. California gardens, the first green appears around February and flowering commences in late April or early May.  Flowering can last up to three to four weeks.

California brodiaea (Brodiaea californica) : foliage
 
The leaves of Brodiaea californica are long and narrow – up to ½ inch wide and 24 inches long.  Like most in this genus, the leaves are fleshy and medium green.  In a dry spring, the leaves will begin to yellow and dry at their tips as flowering begins.
 
California brodiaea (Brodiaea californica) : flower and buds
 
Flowers are grouped in starburst-like umbels atop stout stems.  Each umbel contains 8-12 upright flowers, each flower about 1-1 ½ inches (2.4-3.8 cm) in length (see above).  The flowers may be white or pale pink, but those in Mother Nature’s Backyard are a lovely pale lavender. 

California brodiaea (Brodiaea californica) : close-up of flowers
 
The flowers themselves have a specialized form.  The perianth (fused petals and sepals; three of each) forms a long tube with a flared opening (see above).  The pollen-producing stamens are surrounded by an upright, white, tube-like structure formed by the staminodia (sterile stamens).    

Such specialized floral architecture often reflects adaptation to specific types of pollinators.  We recently observed a hummingbird carefully visiting every flower.  We were surprised to learn that little is known about the pollination of Brodiaea californica.  We will continue to observe and photograph any potential pollinators, with the goal of adding to our knowledge of this species. We’ll also be more observant regarding the production of viable seeds.   Here’s hoping!

California brodiaea (Brodiaea californica) : lovely late spring color
 
California brodiaea is an easy plant to grow.  Once planted in the ground or in a pot, it needs only adequate winter/spring moisture and relatively dry conditions through the summer/fall to succeed and multiply.  In fact, as it hails from N. California, these corms can even take occasional summer water – just don’t over-do.

California brodiaea does fine in full sun to part-shade; morning sun is probably optimal in our drier S. California gardens.  If you’re growing it in a container, provide a layer of fresh potting mix or ½ strength fertilizer in winter/early spring.

 If flowering starts to decrease – or pots seem over-crowded – thin the corms in the fall. You’ll probably only need to do this every third or fourth year.  For more on caring for native corms, see: http://mother-natures-backyard.blogspot.com/2017/02/gardening-with-california-native-bulbs.html
 
California brodiaea (Brodiaea californica) : glorious massed
 
This is truly one of the prettiest California native ‘bulbs’.  The robust foliage and flowers compete well with other native wildflowers.  We love the look of it with California poppy, the Clarkias and Gilias.   Masses of Brodiaea californica provide pastel color when many spring-flowering annuals are already done for the season (in S. California).  We welcome anything that provides color in the ‘between seasons’ period of May and early June.

Its size makes Brodiaea californica a good candidate for the foreground in mixed beds.  It also makes a good filler around perennial grasses, shrubs and herbaceous perennials.  This is one of our all-time favorites for containers; it’s truly a conversation piece. Place a container of California brodiaea near an outdoor seating area for maximum enjoyment.    The corms were apparently eaten by native Californians, though we have yet to try them.   We’ll try to learn more about their preparation.

In summary, California brodiaea is one of our favorite native ‘bulbs’.  It’s pretty, adaptable, robust and easy to grow.  We hope you’ll consider adding a pot or two to your own garden.   Just remember to order bulbs in summer – they sell out fast!
 
California brodiaea (Brodiaea californica) : lovely container plant
Home garden, Redondo Beach, CA
 
 



For plant information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html

 
 

We welcome your comments (below).  You can also send your questions to: mothernaturesbackyard10@gmail.com
 
 

Saturday, April 29, 2017

Valley Carpenter Bee – Xylocopa varipuncta


Female Valley Carpenter Bee (Xylocopa varipuncta) on California encelia
Mother Nature's Backyard Garden

We love the insects in Mother Nature’s Backyard. In fact, our gardens are specifically designed to attract many types of pollinators, from hummingbirds and bees to moths and flies. But each spring we particularly look forward to the large bees.  Just recently we saw one of our favorites, a female Valley Carpenter Bee (Xylocopa varipuncta).  We thought you might enjoy learning about this interesting native pollinator.  Its scientific name is pronounced: ZIE-low-co-puh  vair-ee-PUNK-tuh).

Valley Carpenter Bee is the largest native bee in California. It belongs to the genus Xylocopa (the Carpenter Bees), a genus with approximately 500 species world-wide.  In general, the Carpenter Bees are large, wood-nesting bees found in a variety of habitats, from the sub-tropics to temperate woodlands. 
 
Female Valley Carpenter Bee (Xylocopa varipuncta) -
busy in spring
 
The Valley Carpenter Bee is native to Southwestern U.S. from California to Texas and south into Northern Baja California, Mexico.   Its common name honors California’s Great Central Valley, where this species does, indeed, occur.  But this bee flies throughout the California Floristic Province (W. of the Sierras) and is fairly common in S. California.   Xylocopa varipuncta lives where ever there is wood for nest-building.  In the wilds, this is most commonly in the lower elevation oak and riparian woodlands of California’s valleys and foothills.  But the species is also seen in urban gardens, particularly those with native plants.

The species Xylocopa varipuncta is the most sexually dimorphic of all the Xylocopa species.  You may have seen the males and females and believed them to be separate species.  Females are large (15-25 mm; ½ to 1 inch), shiny black bees.  They are relatively slow flyers, although they don’t spend long periods on individual flowers.  But if you wait patiently, you can get good pictures of this large bee.

Female Valley Carpenter Bee (Xylocopa varipuncta)
 
The female Xylocopa varipuncta looks like a large, black bumblebee with amber-colored wings.  The body color is black: black head, thorax, abdomen, legs and antennae.  The female body is shiny, but closer inspection shows that legs, thorax and posterior abdomen are actually quite hairy.  In fact, females can pick up quite a load of pollen, making them look superficially like a black and yellow bumblebee (see below).
 
Female Valley Carpenter Bee (Xylocopa varipuncta) on
 Arroyo Lupine.  Note yellow pollen.
 
Male Valley Carpenter Bees are smaller, very hairy and a striking golden brown color. They also have amazing pale green eyes - there is no other California bee like them.  They are sometimes called ‘Teddy Bear Bees’ because of their resemblance to the childhood toy.  In fact, the males can be aggressive to other bees, but are quite harmless to humans; only the females can sting (and then, usually only when you’re harassing them).

The males have been difficult for us to photograph.  They are shy creatures that are almost always in motion. We’ll keep trying, and post photos when we get some.  For good photographs of both males and females, we recommend references 2, 3 and 4, below.

Like all of the Carpenter bees, Xylocopa varipuncta nests in cavities in wood. The females excavate the tunnels with their stout mandibles (jaws), usually choosing softer wood like willow or partly decomposing limbs, stumps or logs.  While not a ‘challenge’ species like the Eastern Carpenter Bees, in urban areas Xylocopa varipuncta sometimes nests in unpainted, untreated wood (like redwood posts).

It takes quite a strong bee to be able to chew through wood!   We recently drilled some ‘starter holes’ in a stump.  A female Carpenter bee has been eyeing them – perhaps she’ll stay?    There are so many places for cavity-dwelling bees to nest in a preserve like the Gardena Willows Wetland Preserve (where our gardens are located). 

Female Valley Carpenter Bee (Xylocopa varipuncta)
 checks potential nest site
 
Valley Carpenter bees overwinter as adults in these tunnels, emerging in the spring (our earliest photos in western Los Angeles County are from early January).  Then the females start to forage and the males start to cruise.  There is much work to be done in spring. First, mating must occur. And then the nesting cavities must be prepared and provisioned, all prior to egg laying.

Valley Carpenter Bees are adaptable.  If hollow-stemmed plants (like bamboo or Elderberry) are available, they create unbranched, linear nests in the stems.  If not, they create or enlarge branched nests in wood.  The branched nests usually contain 6-8 chambers; each will contain a single egg, as well as a supply of ‘bee bread’.  The ‘bee bread’ is a mixture of pollen and nectar made by the female.  It supplies food for the developing bee.

Like everything about Xylocopa varipuncta, their eggs are large (about ½ inch long or a little more; 12-15 mm).  The larvae develop in the nest, emerging as adults in late summer (usually August).   You can often see young adults nectaring in the summer and early fall garden.  The bees hibernate in the nest tunnels over winter, emerging again in the spring or late winter (as early as January in western Los Angeles County).

The mating behavior of Xylocopa varipuncta has been well-studied.  There are many fascinating aspects – more than we can discuss in this short posting.  We refer the interested reader to an excellent Wikipedia posting on the species [ref. 1].

As native plant gardeners, we encounter more insect species than do conventional gardeners.  This is a good thing; it in part explains why native plant gardens tend to be more productive and pest-free than other local gardens.  But, how do we evaluate – and explain to our neighbors – whether a particular insect is a pest or beneficial insect?   We suggest weighing the potential harms against the potential benefits.

The potential harms associated with the Valley Carpenter Bee are two: 1) nesting in wood structures; 2) stings.  Given the choice, Valley Carpenter Bees will choose to nest in dead limbs, trunks, stems and other natural sites, rather than in structural wood [5].  They particularly avoid painted or treated wood.  So, unless you have untreated pine, redwood or cedar, nesting is unlikely to be a problem with our western Carpenter Bees.  You might even want to provide a ‘bee house’ or pieces of logs as suitable alternative nesting places.   And as to the stings, the females are really pretty docile.  They’ll only sting to protect themselves; given the choice, they prefer to avoid you.

As to the services Valley Carpenter Bees provide?  We see at least three: 1) pollination; 2) recycling dead wood; 3) human enjoyment.  The second service is most important in natural settings. In Preserves, parks and other natural areas, cavity-builders help begin the process of breaking down old wood. This is an extremely important service – but not much observed in most gardens. 

Female Valley Carpenter Bee (Xylocopa varipuncta) pollinating
 Tansy phacelia (Phacelia tanacetifolia)
 
Valley Carpenter Bees are important and efficient pollinators.  They can regulate their body temperature [1], allowing them to fly in temperatures both cooler and warmer than other pollinators.  Their hairy bodies allow them to pick up plenty of pollen and transport it to other flowers. They are also capable of ‘buzz pollination’ – literally shaking pollen from the anthers by vibrating their flight muscles.

Studies have shown that Carpenter Bees are more effective pollinators than European Honeybees for such varied plants as Passion vine, cotton, tomatoes and melons.  So we should welcome them into our gardens, and provide them sources of nectar from early spring into fall.
 

 

Nectar is the primary source of food and water for adult Xylocopa varipuncta. Obtaining nectar is easy from many flowers.  But some good nectar sources (including Manzanitas, Penstemons and other tubular flowers) present a real challenge for large bees.  Nectar is located deep within the floral tube, accessible only to those small enough or possessing a long tongue. This ensures that only the right creatures – those who actually perform the service of pollination – can access the nectar.
 

Female Valley Carpenter Bee (Xylocopa varipuncta) -
'stealing' nectar from Manzanita
 
The Valley Carpenter gets around this problem by cutting a slit in the floral tube and ‘stealing’ the nectar, without picking up any pollen in the process (see photo above).  These bees even pierce nectar-less flowers, possibly obtaining water, minerals or other chemicals from the plant sap [6].   So yes, these guys can be (adorable) thieves!

 

And that brings us to the last benefit of Xylocopa varipuncta in the home garden; the enjoyment we get from watching these interesting creatures.  Carpenter bees are large enough for all to observe.  Even the very young and the octogenarian can enjoy their antics.  Many a future biologist has been enthralled by garden bees and other insects. 

In fact, there’s much still to be learned about these bee’s behaviors. That’s the wonderful thing about insects: they’re all around us, yet they remain surprisingly un-studied.  Perhaps you, your child or grandchild, sitting in your garden, will discover something important.  All you need is time, a pair of binoculars (or good eyesight) and a garden that provides for our native pollinators.  What a bargain!

 
 


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We encourage your comments below.   If you have questions about Duskywing butterflies or other gardening topics you can e-mail us at :  mothernaturesbackyard10@gmail.com