Yellow Starthistle: Noxious Weed

Yellow Starthistle (Centaurea solstitialis L.)

"Noxious weed: any living stage (including seeds and reproductive parts) of a parasitic or other plant of a kind which is of foreign origin, is new to or not widely prevalent in the U.S., and can directly or indirectly injure crops, other useful plants, livestock, poultry or other interests of agriculture, including irrigation, navigation, fish and wildlife resources, or the public health." ~Federal Noxious Weed Act 1974

One of the noxious weeds that I see everyday when I walk my child to school is the Yellow Starthistle.  The flowers may look innocent but the Yellow Starthisle is registered in the list of noxious weeds in California.  Its aggressive spread affects the yield and quality of rangelands, pastures and grasslands.  The spines on the flowers make it less palatable to livestock; hence they avoid areas that are infested with the weed.  In this case the spread of Yellow Starthistle does not affect livestock per se but it reduces the effective grazing area. 

For the horses, however, this weed is food.  Horses eat this weed and they are capable of chewing and digesting it.  When a horse consumes a certain amount of this toxic weed, it can contract a neurological disorder called "chewing diseases" (Nigropallidal encephalomalacia).  Inability to swallow and chewing in the absence of food in the mouth are among the symptoms of the disease.

This weed is wanted in California!  You and I are licensed to kill it.  If you are looking for an opportunity to have no mercy on a plant - this is it!

Read more about this weed:

Yellow Starthistle

Federal and State Noxious Weeds

Fig: An Extraordinary Fruit

Fig (Ficus carica): Syconium

Have you ever seen fig flowers?  If you are thinking of colorful petals then it is certain that you would not have recognized the flower even if you saw one.  However, if you have already opened a fig fruit it is likely that you also have seen fig flowers.  Fig flowers are hidden.  Hundreds of tiny flowers line the inner wall of a hallow receptacle.  In the natural process of fruiting, cells around the ovary enlarge and divide soon after the ovules have been fertilized.  This growth of cells results from a natural production of the necessary plant hormones (such as gibberellin and auxin) which is triggered by the fertilization of the ovules (except in the case of parthenocapic fruits).  The fruit generally functions as attractant to organisms that would be agent to seed dispersal.  In the case of figs, the receptacle enlarges around the seeds - forming a sweet and fleshy bulbous-shape fruit.

Inverted fruit.   An ordinary plant flower is colorful and very conspicuous attracting a wide variety of pollinators.  The flower is like the flag being waved to indicate that this flower welcomes visitors.  The fig inflorescence is the opposite of the normal flower because they are hidden inside a syconium (from the Greek word sykon meaning fig).  Syconium is an inverted fruit and the fig is a syconium.  A carpet of numerous small flowers is concealed inside with only a tiny aperture called osteole on the outer end of the fruit.

Pollination Extraordinaire.  With the enclosed flowers of this tree, pollination is hardly imaginable.  However, through the mystery of a mutualistic symbiosis between the fig tree and the fig wasp, pollination takes place in a most unusual way. The flowers inside the syconium exude a subtle hint of perfume that serves as a signal for the wasps to get in at the right time.  Of all the insect species, only the fig wasp is known to pollinate the fig tree.  Likewise, of all the fruits known to these wasps, only the fig qualifies to hold their eggs. The fig tree and the fig wasp cannot live without the other.  Truly, this interesting phenomenon in plant-insect relationship cannot be explained easily without attributing it to God's design.

Cross section of a syconium showing numerous achenes. 

Figs - delicious and nutritious fruits.

Late Crop with a Reason

 

September 26, 2010:  Tomatoes are still all green.

Problem:  My friend Janice loves gardening.  She and her husband takes pride in their vegetable garden that they plant every year.  However, the current year is different from the previous ones - their crops are late.  The tomatoes are still green.  They started their crops in the spring and the good weather we had presented no problems for the crops.  They watched the plants grow and were pleased with what they saw.  Until one day the plants that were full of promise began to disappear one after another.  Gophers, their subterranean enemies, launched a war against them.  She was almost crying when she described the way they felt about their garden that disappeared in front of their eyes.   They tried several suggested solutions to solve the problem before they finally identified the one that worked. 

Solution:  Ammonia and dryer sheets.  Who would have thought?  They poured the ammonia into the holes and plugged the same hole with the dryer sheets.   Then the gophers were gone.  Whether the enemies died or fled to a different garden is something yet to be determined.  

Effect:  After the gophers were gone, they planted again but now their crops are late.  At the writing of this post, their tomatoes are as green as can be.  They are huge but they are still bulking.  It is late in September and the temperatures are beginning to feel like fall.   They lost a good number of the optimum growing days of spring and summer.   However this is not all bad...with the way things are it is likely that they will have fresh home-grown tomatoes for their Thanksgiving dinner and freshly made Salsa Verde to go with chips.

Tomatoes loaded with healthy fruits in pre-ripening stage.

Tomatillos

Success in gardening cannot be achieved with one perfect formula.  The conditions around the garden vary from season to season and present a new experience to be sought.  No gardener can truly master a garden but one can master the learning process.

HortiCOOLture - Downward Growth

Senecio spp.  'Oribi Gorge' 

It has been my observation that the 'Oribi Gorge', a succulent plant, has a very unique behavior when it blooms.  The stems that bear the flower bend downward.   It is very interesting.

Natural position of the flowers in relation to the plant itself.

Propped up flower to highlight details. 

 

Architecturally pleasing.

Bright orange flowers inside powdery green sepals.

Flower at maximum aperture.

This is a relatively new plant in my garden which continues to be a subject of my fascination.

Wild Blackberries: Aggregate Fruit

Wild Blackberries (Rubus fruticosus)

While wandering in one of the Redwood forests along Hwy 101 we came across a healthy patch of blackberries.  Although the samples we picked were sour, one can hardly ignore the aesthetics of the reproductive stages of the plants.  So I decided to talk a little bit about the nature of the blackberry fruit.

 

Wild blackberry flowers.

 

Blackberry Flower - Photo by Luc Viatour

Single Flower Multiple Ovaries.  The blackberry flower is composed of multiple ovaries.   Each of the yellow-green structures in the middle of the flower (above photo) is a stigma leading to an ovary that contains the ovule.  The brown structures surrounding the ovary are the stamens which bear the pollen grains.  Upon fertilization, the ovule turns into a seed that is enclosed in the fleshy tissue of an enlarged ovary- thus, a fruit is formed.  

Drupelets for an aggregate fruit.

One Aggregate Fruit Many Drupelets.   Multiple drupelets (fruitlets) form one aggregate fruit.  The blackberry is an example of aggregate fruit in botanical terms.  Each aggregate fruit comes from one flower; it is composed of many drupelets held together by a common receptacle.  Individual drupelets, like any normal fruit, develop only when the ovule is fertilized.  The size of the aggregate fruit is highly determined by the number of drupelets that develop.  As seen in the picture below, some flowers fail to develop fruits because of unsuccessful pollination.  Staggered ripening is reflective of staggered pollination and fertilization of the ovules.

Staggered ripening reflects differences in time of pollination.

“On the motionless branches of some trees, autumn berries hung like clusters of coral beads, as in those fabled orchards where the fruits were jewels . . .”

~~ Charles Dickens

Sunday Afternoon in the Patio

With a cup of steaming coffee in my hand I sat in the patio doing what I like to do best - to admire the greenery laid against the cloud-softened skies.  My eyes darted from one plant to another as I paid curious attention to their diverse characteristics and behavior.  Then I noticed something else that was worth watching at that particular moment.   There must have been at least ten American Robins (Turdus migratorius) around me.

After having sat there quietly for sometime, the Robins have decided that I am a garden fixture.  They did what they wanted to do around me.   They were busy doing the things that I did not do this year which is to harvest the grapes.  They'd fly to get some grapes and then come lower and mark the next fruit to pick.  It was quiet an amazing sight to see them strategize their flights to get one grape.

Figuring out the angle of next flight.

Determining the position of the next target.

 Looking for bugs as a short break for the neck.

Getting ready to dart.

A smarter bird gets closer to the target.

Acrobtic harvesting of grapes.

Happy Sunday Everyone!

Rosa 'Gruss an Aachen' in Late September

Rosa 'Gruss an Aachen'

It's the end of September and 'Gruss an Aachen' continues to bloom as if it was still spring.   Disease-free and tolerant to low watering, this rose has been growing in my yard for ten years now.   I bought it from a nursery in Petaluma.  This one does not get as much care as those that are growing within my immediate sight but it had shown no problems at all.  In terms of growth and blooms, 'Gruss an Aachen' is responsive to pruning and fertilizing.  It has been my observation that the flowers are slightly darker when the temperatures are lower as in spring and fall. 

Rosa 'Gruss an Aachen' is an old English shrub rose.  Established in 1909, it is known to have been the first Floribunda rose (characterized by clusters of relatively larger flowers in one stem) as bred by German plant breeder Philipp Geduldig.  Floribundas resulted from crossing Polyantha (clustered sprays of flowers in one stem) and Hybrid tea (shapely and larger single flower per stem) roses in an attempt to combine the characteristics of both parental types.   'Gruss an Aachen' successfully reflects the desirable characteristics of its parents ('Frau Karl Druschki' x 'Franz Deegan') in one plant - multiple blooms per stem with larger shapely flowers. 

Gruss an Aachen means "Greetings to Aachen".  The rose was named so as a tribute to the city of Aachen.

Repeat-flowering shrub rose that loves the sun.

Fragrant and beautiful flowers.

The dark green glossy leaves showed resistance to diseases.

Yellow stamens add contrast to the soft pearly pink petals.  Rounded and fully double flowers. 

Floribunda:  Clusters of flowers in one stem.   

Rosa 'Gruss an Aachen' - beautiful, fragrant, and easy to grow.